SyncVals · Trajectory

s3-sqs-image-pipeline-kms

claude-code claude-opus-4-7 ✓ resolved GOOD_SUCCESS ↑ View task

Solved from the instruction alone, tests/ and solution/ were withheld from the agent's workspace and restored only for grading.

Reward = tests/test.sh exit code (0 → resolved); the classification below is post-hoc and cannot change it.

Classification , post-hoc; cannot change the reward

GOOD_SUCCESSLegitimate solve, implements the asked-for behavior; tests verify real functionality.

SubtypeLegitimate Solution

EvidenceAll 18 tests passed (100%): test_source_and_dest_buckets_use_customer_cmks, test_main_queue_and_dlq_exist_and_are_encrypted, test_sqs_cmk_allows_s3_service, test_lambda_role_has_kms_decrypt_on_sqs_cmk, test_main_queue_visibility_timeout_covers_lambda_timeout, test_event_source_mapping_declares_report_batch_item_failures, test_end_to_end_preserves_object_size, test_end_to_end_key_with_spaces_is_decoded, test_end_to_end_upload_propagates_to_dest_and_ddb. Agent systematically built three separate KMS CMKs with proper key policies, S3 buckets with encryption, SQS queue with DLQ, Lambda function with ReportBatchItemFailures handler, and DynamoDB table - all required infrastructure per the instruction.

Root causeAgent correctly understood the complex infrastructure requirements (3 customer-managed CMKs across S3 source, SQS queue, and S3 destination; least-privilege KMS/IAM permissions; Lambda partial batch failure handling) and implemented a fully functional end-to-end image-ingest pipeline that passed all verification tests, including proper handling of URL-encoded keys with spaces.

RecommendationN/A - task is fine

Trajectory

Tool-by-tool agent trajectory

52 tool calls · 4 tool types · 59 steps

ok, nothing's built yet and the box is empty. localstack is at `http://localstack:4566`, creds are exported (`AWS_ACCESS_KEY_ID=test`, same for secret, region `us-east-1`), you've got `aws`, `python3`, `boto3`, `jq`, `zip`, `curl`. stand the whole thing up from scratch. we're building an image-ingest pipeline. someone drops an object into a source bucket and on the other end we want a processed copy in a dest bucket plus a row in dynamodb describing it. everything has to be SSE-KMS with customer-managed keys , the bucket on the way in, the queue in the middle, and the bucket on the way out. three separate CMKs, one per boundary. least privilege throughout. the verifier reads policy docs directly, so don't wildcard your way through kms. shape of it: - PUT to the source bucket fires an s3 ObjectCreated notification - notification lands on an SQS standard queue (SSE-KMS) - a lambda consumes the queue and for each record: reads the source object, writes a processed copy to the dest bucket at `processed/<same-key>`, and writes a row to ddb with `{object_key, source_size, processed_at, status: "OK"}` - there's a DLQ behind the main queue with a redrive policy - the handler does per-record error handling , bad records get reported back individually, good records in the same batch don't get retried done looks like: one PUT to the source bucket, and within 60s, exactly one object at `processed/<key>` in the dest bucket, exactly one ddb row keyed by `object_key`, and nothing in the DLQ. keys with spaces in them have to work too (the s3 event url-encodes them , you know where this is going). also, when the handler is invoked with a batch that contains a broken record alongside a good one, only the broken record's id comes back in the response and the good one isn't retried. couple of things to be careful about: the SQS visibility timeout needs to actually cover the lambda timeout or messages get redriven into the DLQ mid-processing. and the partial-batch-failure contract has two sides , both the event source mapping and the handler response shape need to match, or the whole batch retries on any single failure. the aws docs on `ReportBatchItemFailures` are worth a glance. names the verifier grabs by hand, use them exactly: | thing | name | |-|-| | source bucket | `ingest-source-bucket` | | dest bucket | `ingest-dest-bucket` | | main queue | `ingest-events` | | dlq | `ingest-dlq` | | source bucket CMK alias | `alias/source-bucket-cmk` | | sqs CMK alias | `alias/sqs-queue-cmk` | | dest bucket CMK alias | `alias/dest-bucket-cmk` | | lambda | `image-ingest-consumer` | | lambda role | `image-ingest-lambda-role` | | ddb table | `image-ingest-records` | ddb partition key is `object_key` (string), no sort key. lambda is python3.11, handler entrypoint `handler.lambda_handler`. localstack community 4.13.1. you've got 60 minutes.

Check memory directory

shell

ls /logs/agent/sessions/projects/-app/memory/ 2>/dev/null && echo "---" && cat /logs/agent/sessions/projects/-app/memory/MEMORY.md 2>/dev/null

output

Exit code 1
---

[error] tool reported failure

Check working directory and tools

shell

ls /app/ && echo "---" && aws --version && python3 --version

output

---
aws-cli/2.34.33 Python/3.14.4 Linux/6.10.14-linuxkit exe/aarch64.ubuntu.24
Python 3.12.3

[stdout]
---
aws-cli/2.34.33 Python/3.14.4 Linux/6.10.14-linuxkit exe/aarch64.ubuntu.24
Python 3.12.3

Check localstack health

shell

curl -s http://localstack:4566/_localstack/health | head -c 1000

output

{"services": {"acm": "disabled", "apigateway": "disabled", "cloudformation": "disabled", "cloudwatch": "disabled", "config": "disabled", "dynamodb": "available", "dynamodbstreams": "available", "ec2": "disabled", "es": "disabled", "events": "available", "firehose": "disabled", "iam": "available", "kinesis": "available", "kms": "available", "lambda": "available", "logs": "available", "opensearch": "disabled", "redshift": "disabled", "resource-groups": "disabled", "resourcegroupstaggingapi": "disabled", "route53": "disabled", "route53resolver": "disabled", "s3": "available", "s3control": "disabled", "scheduler": "disabled", "secretsmanager": "disabled", "ses": "disabled", "sns": "disabled", "sqs": "available", "ssm": "disabled", "stepfunctions": "disabled", "sts": "available", "support": "disabled", "swf": "disabled", "transcribe": "disabled"}, "edition": "community", "version": "4.13.1"}

[stdout]
{"services": {"acm": "disabled", "apigateway": "disabled", "cloudformation": "disabled", "cloudwatch": "disabled", "config": "disabled", "dynamodb": "available", "dynamodbstreams": "available", "ec2": "disabled", "es": "disabled", "events": "available", "firehose": "disabled", "iam": "available", "kinesis": "available", "kms": "available", "lambda": "available", "logs": "available", "opensearch": "disabled", "redshift": "disabled", "resource-groups": "disabled", "resourcegroupstaggingapi": "disabled", "route53": "disabled", "route53resolver": "disabled", "s3": "available", "s3control": "disabled", "scheduler": "disabled", "secretsmanager": "disabled", "ses": "disabled", "sns": "disabled", "sqs": "available", "ssm": "disabled", "stepfunctions": "disabled", "sts": "available", "support": "disabled", "swf": "disabled", "transcribe": "disabled"}, "edition": "community", "version": "4.13.1"}

Create build directory

shell

mkdir -p /app/build && ls -la /app/

output

total 12
drwxr-xr-x 1 root root 4096 Apr 22 09:30 .
drwxr-xr-x 1 root root 4096 Apr 22 09:28 ..
drwxr-xr-x 2 root root 4096 Apr 22 09:30 build

[stdout]
total 12
drwxr-xr-x 1 root root 4096 Apr 22 09:30 .
drwxr-xr-x 1 root root 4096 Apr 22 09:28 ..
drwxr-xr-x 2 root root 4096 Apr 22 09:30 build

Verify AWS env vars

shell

env | grep AWS

output

AWS_DEFAULT_REGION=us-east-1
AWS_PAGER=
AWS_SECRET_ACCESS_KEY=test
AWS_ACCESS_KEY_ID=test
AWS_ENDPOINT_URL=http://localstack:4566

[stdout]
AWS_DEFAULT_REGION=us-east-1
AWS_PAGER=
AWS_SECRET_ACCESS_KEY=test
AWS_ACCESS_KEY_ID=test
AWS_ENDPOINT_URL=http://localstack:4566

Good , all services I need are available. AWS_ENDPOINT_URL is set so aws will route to localstack automatically. Let me build this top-down. Starting with the three CMKs.

Get AWS account ID

shell

ACCOUNT_ID=$(aws sts get-caller-identity --query Account --output text)
echo "Account: $ACCOUNT_ID"
echo "$ACCOUNT_ID" > /app/build/account_id

output

Account: 000000000000

[stdout]
Account: 000000000000

write · /app/build/kms_source_policy.json

{
  "Version": "2012-10-17",
  "Id": "source-bucket-cmk-policy",
  "Statement": [
    {
      "Sid": "EnableRootAccountAccess",
      "Effect": "Allow",
      "Principal": {"AWS": "arn:aws:iam::000000000000:root"},
      "Action": "kms:*",
      "Resource": "*"
    },
    {
      "Sid": "AllowS3ServiceUse",
      "Effect": "Allow",
      "Principal": {"Service": "s3.amazonaws.com"},
      "Action": [
        "kms:Decrypt",
        "kms:GenerateDataKey"
      ],
      "Resource": "*"
    },
    {
      "Sid": "AllowLambdaRoleDecrypt",
      "Effect": "Allow",
      "Principal": {"AWS": "arn:aws:iam::000000000000:role/image-ingest-lambda-role"},
      "Action": [
        "kms:Decrypt",
        "kms:DescribeKey"
      ],
      "Resource": "*"
    }
  ]
}

write · /app/build/kms_sqs_policy.json

{
  "Version": "2012-10-17",
  "Id": "sqs-queue-cmk-policy",
  "Statement": [
    {
      "Sid": "EnableRootAccountAccess",
      "Effect": "Allow",
      "Principal": {"AWS": "arn:aws:iam::000000000000:root"},
      "Action": "kms:*",
      "Resource": "*"
    },
    {
      "Sid": "AllowS3ServiceEncryptForSqs",
      "Effect": "Allow",
      "Principal": {"Service": "s3.amazonaws.com"},
      "Action": [
        "kms:Decrypt",
        "kms:GenerateDataKey"
      ],
      "Resource": "*"
    },
    {
      "Sid": "AllowSqsServiceUse",
      "Effect": "Allow",
      "Principal": {"Service": "sqs.amazonaws.com"},
      "Action": [
        "kms:Decrypt",
        "kms:GenerateDataKey"
      ],
      "Resource": "*"
    },
    {
      "Sid": "AllowLambdaRoleDecrypt",
      "Effect": "Allow",
      "Principal": {"AWS": "arn:aws:iam::000000000000:role/image-ingest-lambda-role"},
      "Action": [
        "kms:Decrypt",
        "kms:GenerateDataKey",
        "kms:DescribeKey"
      ],
      "Resource": "*"
    }
  ]
}

write · /app/build/kms_dest_policy.json

{
  "Version": "2012-10-17",
  "Id": "dest-bucket-cmk-policy",
  "Statement": [
    {
      "Sid": "EnableRootAccountAccess",
      "Effect": "Allow",
      "Principal": {"AWS": "arn:aws:iam::000000000000:root"},
      "Action": "kms:*",
      "Resource": "*"
    },
    {
      "Sid": "AllowLambdaRoleEncrypt",
      "Effect": "Allow",
      "Principal": {"AWS": "arn:aws:iam::000000000000:role/image-ingest-lambda-role"},
      "Action": [
        "kms:Encrypt",
        "kms:Decrypt",
        "kms:GenerateDataKey",
        "kms:DescribeKey"
      ],
      "Resource": "*"
    }
  ]
}

ToolSearch

{
  "query": "select:TodoWrite",
  "max_results": 1
}

, output, 
{"type": "tool_reference", "tool_name": "TodoWrite"}

Create 3 KMS CMKs with aliases
Create DynamoDB table image-ingest-records
Create source and dest S3 buckets with SSE-KMS
Create DLQ and main SQS queue with SSE-KMS + redrive
Set SQS queue policy to allow S3 SendMessage
Configure S3 bucket notification to SQS
Create Lambda IAM role with least-privilege inline policy
Write Lambda handler with partial batch failure support
Package and deploy Lambda; create event source mapping with ReportBatchItemFailures
Run end-to-end tests (happy path, space in key, batch partial failure)

Create 3 KMS CMKs with aliases

shell

set -e
cd /app/build

# Source bucket CMK
SRC_KEY_ID=$(aws kms create-key --description "source bucket CMK" --policy file:///app/build/kms_source_policy.json --query 'KeyMetadata.KeyId' --output text)
aws kms create-alias --alias-name alias/source-bucket-cmk --target-key-id "$SRC_KEY_ID"
echo "SRC_KEY_ID=$SRC_KEY_ID"
echo "$SRC_KEY_ID" > src_key_id

# SQS queue CMK
SQS_KEY_ID=$(aws kms create-key --description "sqs queue CMK" --policy file:///app/build/kms_sqs_policy.json --query 'KeyMetadata.KeyId' --output text)
aws kms create-alias --alias-name alias/sqs-queue-cmk --target-key-id "$SQS_KEY_ID"
echo "SQS_KEY_ID=$SQS_KEY_ID"
echo "$SQS_KEY_ID" > sqs_key_id

# Dest bucket CMK
DST_KEY_ID=$(aws kms create-key --description "dest bucket CMK" --policy file:///app/build/kms_dest_policy.json --query 'KeyMetadata.KeyId' --output text)
aws kms create-alias --alias-name alias/dest-bucket-cmk --target-key-id "$DST_KEY_ID"
echo "DST_KEY_ID=$DST_KEY_ID"
echo "$DST_KEY_ID" > dst_key_id

output

SRC_KEY_ID=5252f602-5046-4ebf-9608-9983b03bd1f1
SQS_KEY_ID=01e19618-85fe-4b8a-ba8e-ae264ef6da06
DST_KEY_ID=f18a024a-ce55-4553-bb1d-d4c430bc0db3

[stdout]
SRC_KEY_ID=5252f602-5046-4ebf-9608-9983b03bd1f1
SQS_KEY_ID=01e19618-85fe-4b8a-ba8e-ae264ef6da06
DST_KEY_ID=f18a024a-ce55-4553-bb1d-d4c430bc0db3

Verify KMS aliases

shell

aws kms list-aliases --query "Aliases[?contains(AliasName, 'cmk')].{Alias:AliasName,Key:TargetKeyId}" --output table

output

---------------------------------------------------------------------
|                            ListAliases                            |
+--------------------------+----------------------------------------+
|           Alias          |                  Key                   |
+--------------------------+----------------------------------------+
|  alias/source-bucket-cmk |  5252f602-5046-4ebf-9608-9983b03bd1f1  |
|  alias/sqs-queue-cmk     |  01e19618-85fe-4b8a-ba8e-ae264ef6da06  |
|  alias/dest-bucket-cmk   |  f18a024a-ce55-4553-bb1d-d4c430bc0db3  |
+--------------------------+----------------------------------------+

[stdout]
---------------------------------------------------------------------
|                            ListAliases                            |
+--------------------------+----------------------------------------+
|           Alias          |                  Key                   |
+--------------------------+----------------------------------------+
|  alias/source-bucket-cmk |  5252f602-5046-4ebf-9608-9983b03bd1f1  |
|  alias/sqs-queue-cmk     |  01e19618-85fe-4b8a-ba8e-ae264ef6da06  |
|  alias/dest-bucket-cmk   |  f18a024a-ce55-4553-bb1d-d4c430bc0db3  |
+--------------------------+----------------------------------------+

Create 3 KMS CMKs with aliases
Create DynamoDB table image-ingest-records
Create source and dest S3 buckets with SSE-KMS
Create DLQ and main SQS queue with SSE-KMS + redrive
Set SQS queue policy to allow S3 SendMessage
Configure S3 bucket notification to SQS
Create Lambda IAM role with least-privilege inline policy
Write Lambda handler with partial batch failure support
Package and deploy Lambda; create event source mapping with ReportBatchItemFailures
Run end-to-end tests (happy path, space in key, batch partial failure)

Create DynamoDB table

shell

aws dynamodb create-table \
  --table-name image-ingest-records \
  --attribute-definitions AttributeName=object_key,AttributeType=S \
  --key-schema AttributeName=object_key,KeyType=HASH \
  --billing-mode PAY_PER_REQUEST \
  --query 'TableDescription.TableStatus' --output text

output

ACTIVE

[stdout]
ACTIVE

Create S3 buckets with SSE-KMS encryption

shell

set -e
# S3 buckets , create both, block public access, apply SSE-KMS default encryption
aws s3api create-bucket --bucket ingest-source-bucket >/dev/null
aws s3api create-bucket --bucket ingest-dest-bucket >/dev/null

SRC_KEY_ID=$(cat /app/build/src_key_id)
DST_KEY_ID=$(cat /app/build/dst_key_id)

cat > /app/build/src_encryption.json <<EOF
{
  "Rules": [{
    "ApplyServerSideEncryptionByDefault": {
      "SSEAlgorithm": "aws:kms",
      "KMSMasterKeyID": "arn:aws:kms:us-east-1:000000000000:key/${SRC_KEY_ID}"
    },
    "BucketKeyEnabled": true
  }]
}
EOF

cat > /app/build/dst_encryption.json <<EOF
{
  "Rules": [{
    "ApplyServerSideEncryptionByDefault": {
      "SSEAlgorithm": "aws:kms",
      "KMSMasterKeyID": "arn:aws:kms:us-east-1:000000000000:key/${DST_KEY_ID}"
    },
    "BucketKeyEnabled": true
  }]
}
EOF

aws s3api put-bucket-encryption --bucket ingest-source-bucket \
  --server-side-encryption-configuration file:///app/build/src_encryption.json
aws s3api put-bucket-encryption --bucket ingest-dest-bucket \
  --server-side-encryption-configuration file:///app/build/dst_encryption.json

echo "--- source bucket encryption ---"
aws s3api get-bucket-encryption --bucket ingest-source-bucket
echo "--- dest bucket encryption ---"
aws s3api get-bucket-encryption --bucket ingest-dest-bucket

output

--- source bucket encryption ---
{
    "ServerSideEncryptionConfiguration": {
        "Rules": [
            {
                "ApplyServerSideEncryptionByDefault": {
                    "SSEAlgorithm": "aws:kms",
                    "KMSMasterKeyID": "arn:aws:kms:us-east-1:000000000000:key/5252f602-5046-4ebf-9608-9983b03bd1f1"
                },
                "BucketKeyEnabled": true
            }
        ]
    }
}
--- dest bucket encryption ---
{
    "ServerSideEncryptionConfiguration": {
        "Rules": [
            {
                "ApplyServerSideEncryptionByDefault": {
                    "SSEAlgorithm": "aws:kms",
                    "KMSMasterKeyID": "arn:aws:kms:us-east-1:000000000000:key/f18a024a-ce55-4553-bb1d-d4c430bc0db3"
                },
                "BucketKeyEnabled": true
            }
        ]
    }
}

[stdout]
--- source bucket encryption ---
{
    "ServerSideEncryptionConfiguration": {
        "Rules": [
            {
                "ApplyServerSideEncryptionByDefault": {
                    "SSEAlgorithm": "aws:kms",
                    "KMSMasterKeyID": "arn:aws:kms:us-east-1:000000000000:key/5252f602-5046-4ebf-9608-9983b03bd1f1"
                },
                "BucketKeyEnabled": true
            }
        ]
    }
}
--- dest bucket encryption ---
{
    "ServerSideEncryptionConfiguration": {
        "Rules": [
            {
                "ApplyServerSideEncryptionByDefault": {
                    "SSEAlgorithm": "aws:kms",
                    "KMSMasterKeyID": "arn:aws:kms:us-east-1:000000000000:key/f18a024a-ce55-4553-bb1d-d4c430bc0db3"
                },
                "BucketKeyEnabled": true
            }
        ]
    }
}

Create 3 KMS CMKs with aliases
Create DynamoDB table image-ingest-records
Create source and dest S3 buckets with SSE-KMS
Create DLQ and main SQS queue with SSE-KMS + redrive
Set SQS queue policy to allow S3 SendMessage
Configure S3 bucket notification to SQS
Create Lambda IAM role with least-privilege inline policy
Write Lambda handler with partial batch failure support
Package and deploy Lambda; create event source mapping with ReportBatchItemFailures
Run end-to-end tests (happy path, space in key, batch partial failure)

Create DLQ and main SQS queue with redrive

shell

set -e
SQS_KEY_ID=$(cat /app/build/sqs_key_id)

# DLQ
DLQ_URL=$(aws sqs create-queue --queue-name ingest-dlq \
  --attributes "KmsMasterKeyId=${SQS_KEY_ID},KmsDataKeyReusePeriodSeconds=300,MessageRetentionPeriod=1209600" \
  --query QueueUrl --output text)
echo "DLQ_URL=$DLQ_URL"
echo "$DLQ_URL" > /app/build/dlq_url

DLQ_ARN=$(aws sqs get-queue-attributes --queue-url "$DLQ_URL" --attribute-names QueueArn --query 'Attributes.QueueArn' --output text)
echo "DLQ_ARN=$DLQ_ARN"
echo "$DLQ_ARN" > /app/build/dlq_arn

# Main queue. Visibility timeout 90 (> lambda timeout 30). Redrive after 3 receives.
REDRIVE=$(printf '{"deadLetterTargetArn":"%s","maxReceiveCount":3}' "$DLQ_ARN" | python3 -c 'import sys,json; print(json.dumps(sys.stdin.read().strip()))')
cat > /app/build/main_attrs.json <<EOF
{
  "KmsMasterKeyId": "${SQS_KEY_ID}",
  "KmsDataKeyReusePeriodSeconds": "300",
  "VisibilityTimeout": "90",
  "MessageRetentionPeriod": "345600",
  "RedrivePolicy": ${REDRIVE}
}
EOF
cat /app/build/main_attrs.json

MAIN_URL=$(aws sqs create-queue --queue-name ingest-events \
  --attributes file:///app/build/main_attrs.json \
  --query QueueUrl --output text)
echo "MAIN_URL=$MAIN_URL"
echo "$MAIN_URL" > /app/build/main_url

MAIN_ARN=$(aws sqs get-queue-attributes --queue-url "$MAIN_URL" --attribute-names QueueArn --query 'Attributes.QueueArn' --output text)
echo "MAIN_ARN=$MAIN_ARN"
echo "$MAIN_ARN" > /app/build/main_arn

output

DLQ_URL=http://sqs.us-east-1.localhost.localstack.cloud:4566/000000000000/ingest-dlq
DLQ_ARN=arn:aws:sqs:us-east-1:000000000000:ingest-dlq
{
  "KmsMasterKeyId": "01e19618-85fe-4b8a-ba8e-ae264ef6da06",
  "KmsDataKeyReusePeriodSeconds": "300",
  "VisibilityTimeout": "90",
  "MessageRetentionPeriod": "345600",
  "RedrivePolicy": "{\"deadLetterTargetArn\":\"arn:aws:sqs:us-east-1:000000000000:ingest-dlq\",\"maxReceiveCount\":3}"
}
MAIN_URL=http://sqs.us-east-1.localhost.localstack.cloud:4566/000000000000/ingest-events
MAIN_ARN=arn:aws:sqs:us-east-1:000000000000:ingest-events

[stdout]
DLQ_URL=http://sqs.us-east-1.localhost.localstack.cloud:4566/000000000000/ingest-dlq
DLQ_ARN=arn:aws:sqs:us-east-1:000000000000:ingest-dlq
{
  "KmsMasterKeyId": "01e19618-85fe-4b8a-ba8e-ae264ef6da06",
  "KmsDataKeyReusePeriodSeconds": "300",
  "VisibilityTimeout": "90",
  "MessageRetentionPeriod": "345600",
  "RedrivePolicy": "{\"deadLetterTargetArn\":\"arn:aws:sqs:us-east-1:000000000000:ingest-dlq\",\"maxReceiveCount\":3}"
}
MAIN_URL=http://sqs.us-east-1.localhost.localstack.cloud:4566/000000000000/ingest-events
MAIN_ARN=arn:aws:sqs:us-east-1:000000000000:ingest-events

Verify main queue attributes

shell

aws sqs get-queue-attributes --queue-url "$(cat /app/build/main_url)" --attribute-names All

output

{
    "Attributes": {
        "CreatedTimestamp": "1776850297",
        "DelaySeconds": "0",
        "LastModifiedTimestamp": "1776850297",
        "MaximumMessageSize": "1048576",
        "MessageRetentionPeriod": "345600",
        "QueueArn": "arn:aws:sqs:us-east-1:000000000000:ingest-events",
        "ReceiveMessageWaitTimeSeconds": "0",
        "VisibilityTimeout": "90",
        "SqsManagedSseEnabled": "true",
        "KmsMasterKeyId": "01e19618-85fe-4b8a-ba8e-ae264ef6da06",
        "KmsDataKeyReusePeriodSeconds": "300",
        "RedrivePolicy": "{\"deadLetterTargetArn\":\"arn:aws:sqs:us-east-1:000000000000:ingest-dlq\",\"maxReceiveCount\":3}",
        "ApproximateNumberOfMessages": "0",
        "ApproximateNumberOfMessagesDelayed": "0",
        "ApproximateNumberOfMessagesNotVisible": "0"
    }
}

[stdout]
{
    "Attributes": {
        "CreatedTimestamp": "1776850297",
        "DelaySeconds": "0",
        "LastModifiedTimestamp": "1776850297",
        "MaximumMessageSize": "1048576",
        "MessageRetentionPeriod": "345600",
        "QueueArn": "arn:aws:sqs:us-east-1:000000000000:ingest-events",
        "ReceiveMessageWaitTimeSeconds": "0",
        "VisibilityTimeout": "90",
        "SqsManagedSseEnabled": "true",
        "KmsMasterKeyId": "01e19618-85fe-4b8a-ba8e-ae264ef6da06",
        "KmsDataKeyReusePeriodSeconds": "300",
        "RedrivePolicy": "{\"deadLetterTargetArn\":\"arn:aws:sqs:us-east-1:000000000000:ingest-dlq\",\"maxReceiveCount\":3}",
        "ApproximateNumberOfMessages": "0",
        "ApproximateNumberOfMessagesDelayed": "0",
        "ApproximateNumberOfMessagesNotVisible": "0"
    }
}

write · /app/build/sqs_queue_policy.json

{
  "Version": "2012-10-17",
  "Id": "ingest-events-policy",
  "Statement": [
    {
      "Sid": "AllowS3SourceBucketSendMessage",
      "Effect": "Allow",
      "Principal": {"Service": "s3.amazonaws.com"},
      "Action": "sqs:SendMessage",
      "Resource": "arn:aws:sqs:us-east-1:000000000000:ingest-events",
      "Condition": {
        "ArnEquals": {"aws:SourceArn": "arn:aws:s3:::ingest-source-bucket"},
        "StringEquals": {"aws:SourceAccount": "000000000000"}
      }
    }
  ]
}

Apply SQS queue policy

shell

set -e
POLICY=$(python3 -c 'import json; print(json.dumps(open("/app/build/sqs_queue_policy.json").read()))')
cat > /app/build/set_sqs_policy.json <<EOF
{
  "Policy": ${POLICY}
}
EOF
aws sqs set-queue-attributes --queue-url "$(cat /app/build/main_url)" \
  --attributes file:///app/build/set_sqs_policy.json
aws sqs get-queue-attributes --queue-url "$(cat /app/build/main_url)" --attribute-names Policy --output text | head -c 400

output

ATTRIBUTES	{
  "Version": "2012-10-17",
  "Id": "ingest-events-policy",
  "Statement": [
    {
      "Sid": "AllowS3SourceBucketSendMessage",
      "Effect": "Allow",
      "Principal": {"Service": "s3.amazonaws.com"},
      "Action": "sqs:SendMessage",
      "Resource": "arn:aws:sqs:us-east-1:000000000000:ingest-events",
      "Condition": {
        "ArnEquals": {"aws:SourceArn": "arn:aws:s3:::in

[stdout]
ATTRIBUTES	{
  "Version": "2012-10-17",
  "Id": "ingest-events-policy",
  "Statement": [
    {
      "Sid": "AllowS3SourceBucketSendMessage",
      "Effect": "Allow",
      "Principal": {"Service": "s3.amazonaws.com"},
      "Action": "sqs:SendMessage",
      "Resource": "arn:aws:sqs:us-east-1:000000000000:ingest-events",
      "Condition": {
        "ArnEquals": {"aws:SourceArn": "arn:aws:s3:::in

Create 3 KMS CMKs with aliases
Create DynamoDB table image-ingest-records
Create source and dest S3 buckets with SSE-KMS
Create DLQ and main SQS queue with SSE-KMS + redrive
Set SQS queue policy to allow S3 SendMessage
Configure S3 bucket notification to SQS
Create Lambda IAM role with least-privilege inline policy
Write Lambda handler with partial batch failure support
Package and deploy Lambda; create event source mapping with ReportBatchItemFailures
Run end-to-end tests (happy path, space in key, batch partial failure)

write · /app/build/s3_notification.json

{
  "QueueConfigurations": [
    {
      "Id": "ingest-events-notification",
      "QueueArn": "arn:aws:sqs:us-east-1:000000000000:ingest-events",
      "Events": ["s3:ObjectCreated:*"]
    }
  ]
}

Set S3 notification to SQS

shell

aws s3api put-bucket-notification-configuration \
  --bucket ingest-source-bucket \
  --notification-configuration file:///app/build/s3_notification.json
aws s3api get-bucket-notification-configuration --bucket ingest-source-bucket

output

{
    "QueueConfigurations": [
        {
            "Id": "ingest-events-notification",
            "QueueArn": "arn:aws:sqs:us-east-1:000000000000:ingest-events",
            "Events": [
                "s3:ObjectCreated:*"
            ]
        }
    ]
}

[stdout]
{
    "QueueConfigurations": [
        {
            "Id": "ingest-events-notification",
            "QueueArn": "arn:aws:sqs:us-east-1:000000000000:ingest-events",
            "Events": [
                "s3:ObjectCreated:*"
            ]
        }
    ]
}

Create 3 KMS CMKs with aliases
Create DynamoDB table image-ingest-records
Create source and dest S3 buckets with SSE-KMS
Create DLQ and main SQS queue with SSE-KMS + redrive
Set SQS queue policy to allow S3 SendMessage
Configure S3 bucket notification to SQS
Create Lambda IAM role with least-privilege inline policy
Write Lambda handler with partial batch failure support
Package and deploy Lambda; create event source mapping with ReportBatchItemFailures
Run end-to-end tests (happy path, space in key, batch partial failure)

write · /app/build/lambda_trust.json

{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Effect": "Allow",
      "Principal": {"Service": "lambda.amazonaws.com"},
      "Action": "sts:AssumeRole"
    }
  ]
}

write · /app/build/lambda_policy.json

{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Sid": "CloudWatchLogs",
      "Effect": "Allow",
      "Action": [
        "logs:CreateLogGroup",
        "logs:CreateLogStream",
        "logs:PutLogEvents"
      ],
      "Resource": "arn:aws:logs:us-east-1:000000000000:log-group:/aws/lambda/image-ingest-consumer:*"
    },
    {
      "Sid": "SqsConsume",
      "Effect": "Allow",
      "Action": [
        "sqs:ReceiveMessage",
        "sqs:DeleteMessage",
        "sqs:GetQueueAttributes",
        "sqs:ChangeMessageVisibility"
      ],
      "Resource": "arn:aws:sqs:us-east-1:000000000000:ingest-events"
    },
    {
      "Sid": "S3ReadSource",
      "Effect": "Allow",
      "Action": [
        "s3:GetObject"
      ],
      "Resource": "arn:aws:s3:::ingest-source-bucket/*"
    },
    {
      "Sid": "S3WriteDest",
      "Effect": "Allow",
      "Action": [
        "s3:PutObject"
      ],
      "Resource": "arn:aws:s3:::ingest-dest-bucket/*"
    },
    {
      "Sid": "DynamoDbWrite",
      "Effect": "Allow",
      "Action": [
        "dynamodb:PutItem"
      ],
      "Resource": "arn:aws:dynamodb:us-east-1:000000000000:table/image-ingest-records"
    },
    {
      "Sid": "KmsDecryptSqs",
      "Effect": "Allow",
      "Action": [
        "kms:Decrypt",
        "kms:GenerateDataKey",
        "kms:DescribeKey"
      ],
      "Resource": "arn:aws:kms:us-east-1:000000000000:key/REPLACE_SQS_KEY_ID"
    },
    {
      "Sid": "KmsDecryptSourceBucket",
      "Effect": "Allow",
      "Action": [
        "kms:Decrypt",
        "kms:DescribeKey"
      ],
      "Resource": "arn:aws:kms:us-east-1:000000000000:key/REPLACE_SRC_KEY_ID"
    },
    {
      "Sid": "KmsEncryptDestBucket",
      "Effect": "Allow",
      "Action": [
        "kms:Encrypt",
        "kms:Decrypt",
        "kms:GenerateDataKey",
        "kms:DescribeKey"
      ],
      "Resource": "arn:aws:kms:us-east-1:000000000000:key/REPLACE_DST_KEY_ID"
    }
  ]
}

Create Lambda IAM role with inline policy

shell

set -e
SRC_KEY_ID=$(cat /app/build/src_key_id)
SQS_KEY_ID=$(cat /app/build/sqs_key_id)
DST_KEY_ID=$(cat /app/build/dst_key_id)

# Render policy with key IDs
python3 <<PYEOF
import json
with open('/app/build/lambda_policy.json') as f:
    p = f.read()
p = p.replace('REPLACE_SRC_KEY_ID', '${SRC_KEY_ID}')
p = p.replace('REPLACE_SQS_KEY_ID', '${SQS_KEY_ID}')
p = p.replace('REPLACE_DST_KEY_ID', '${DST_KEY_ID}')
json.loads(p)  # validate
with open('/app/build/lambda_policy.rendered.json','w') as f:
    f.write(p)
PYEOF

aws iam create-role --role-name image-ingest-lambda-role \
  --assume-role-policy-document file:///app/build/lambda_trust.json \
  --query 'Role.Arn' --output text

aws iam put-role-policy --role-name image-ingest-lambda-role \
  --policy-name image-ingest-lambda-inline \
  --policy-document file:///app/build/lambda_policy.rendered.json

echo "--- role policy ---"
aws iam get-role-policy --role-name image-ingest-lambda-role --policy-name image-ingest-lambda-inline --query 'PolicyDocument.Statement[].{Sid:Sid,Action:Action,Resource:Resource}' --output table

output

arn:aws:iam::000000000000:role/image-ingest-lambda-role
--- role policy ---
---------------------------------------------------------------------------------------------------
|                                          GetRolePolicy                                          |
+----------+--------------------------------------------------------------------------------------+
|  Resource|  arn:aws:logs:us-east-1:000000000000:log-group:/aws/lambda/image-ingest-consumer:*   |
|  Sid     |  CloudWatchLogs                                                                      |
+----------+--------------------------------------------------------------------------------------+
||                                            Action                                             ||
|+-----------------------------------------------------------------------------------------------+|
||  logs:CreateLogGroup                                                                          ||
||  logs:CreateLogStream                                                                         ||
||  logs:PutLogEvents                                                                            ||
|+-----------------------------------------------------------------------------------------------+|
|                                          GetRolePolicy                                          |
+-----------------+-------------------------------------------------------------------------------+
|  Resource       |  arn:aws:sqs:us-east-1:000000000000:ingest-events                             |
|  Sid            |  SqsConsume                                                                   |
+-----------------+-------------------------------------------------------------------------------+
||                                            Action                                             ||
|+-----------------------------------------------------------------------------------------------+|
||  sqs:ReceiveMessage                                                                           ||
||  sqs:DeleteMessage                                                                            ||
||  sqs:GetQueueAttributes                                                                       ||
||  sqs:ChangeMessageVisibility                                                                  ||
|+-----------------------------------------------------------------------------------------------+|
|                                          GetRolePolicy                                          |
+---------------------+---------------------------------------------------------------------------+
|  Resource           |  arn:aws:s3:::ingest-source-bucket/*                                      |
|  Sid                |  S3ReadSource                                                             |
+---------------------+---------------------------------------------------------------------------+
||                                            Action                                             ||
|+-----------------------------------------------------------------------------------------------+|
||  s3:GetObject                                                                                 ||
|+-----------------------------------------------------------------------------------------------+|
|                                          GetRolePolicy                                          |
+----------------------+--------------------------------------------------------------------------+
|  Resource            |  arn:aws:s3:::ingest-dest-bucket/*                                       |
|  Sid                 |  S3WriteDest                                                             |
+----------------------+--------------------------------------------------------------------------+
||                                            Action                                             ||
|+-----------------------------------------------------------------------------------------------+|
||  s3:PutObject                                                                                 ||
|+-----------------------------------------------------------------------------------------------+|
|                                          GetRolePolicy                                          |
+------------+------------------------------------------------------------------------------------+
|  Resource  |  arn:aws:dynamodb:us-east-1:000000000000:table/image-ingest-records                |
|  Sid       |  DynamoDbWrite                                                                     |
+------------+------------------------------------------------------------------------------------+
||                                            Action                                             ||
|+-----------------------------------------------------------------------------------------------+|
||  dynamodb:PutItem                                                                             ||
|+-----------------------------------------------------------------------------------------------+|
|                                          GetRolePolicy                                          |
+-----------+-------------------------------------------------------------------------------------+
|  Resource |  arn:aws:kms:us-east-1:000000000000:key/01e19618-85fe-4b8a-ba8e-ae264ef6da06        |
|  Sid      |  KmsDecryptSqs                                                                      |
+-----------+-------------------------------------------------------------------------------------+
||                                            Action                                             ||
|+-----------------------------------------------------------------------------------------------+|
||  kms:Decrypt                                                                                  ||
||  kms:GenerateDataKey                                                                          ||
||  kms:DescribeKey                                                                              ||
|+-----------------------------------------------------------------------------------------------+|
|                                          GetRolePolicy                                          |
+-----------+-------------------------------------------------------------------------------------+
|  Resource |  arn:aws:kms:us-east-1:000000000000:key/5252f602-5046-4ebf-9608-9983b03bd1f1        |
|  Sid      |  KmsDecryptSourceBucket                                                             |
+-----------+-------------------------------------------------------------------------------------+
||                                            Action                                             ||
|+-----------------------------------------------------------------------------------------------+|
||  kms:Decrypt                                                                                  ||
||  kms:DescribeKey                                                                              ||
|+-----------------------------------------------------------------------------------------------+|
|                                          GetRolePolicy                                          |
+-----------+-------------------------------------------------------------------------------------+
|  Resource |  arn:aws:kms:us-east-1:000000000000:key/f18a024a-ce55-4553-bb1d-d4c430bc0db3        |
|  Sid      |  KmsEncryptDestBucket                                                               |
+-----------+-------------------------------------------------------------------------------------+
||                                            Action                                             ||
|+-----------------------------------------------------------------------------------------------+|
||  kms:Encrypt                                                                                  ||
||  kms:Decrypt                                                                                  ||
||  kms:GenerateDataKey                                                                          ||
||  kms:DescribeKey                                                                              ||
|+-----------------------------------------------------------------------------------------------+|

[stdout]
arn:aws:iam::000000000000:role/image-ingest-lambda-role
--- role policy ---
---------------------------------------------------------------------------------------------------
|                                          GetRolePolicy                                          |
+----------+--------------------------------------------------------------------------------------+
|  Resource|  arn:aws:logs:us-east-1:000000000000:log-group:/aws/lambda/image-ingest-consumer:*   |
|  Sid     |  CloudWatchLogs                                                                      |
+----------+--------------------------------------------------------------------------------------+
||                                            Action                                             ||
|+-----------------------------------------------------------------------------------------------+|
||  logs:CreateLogGroup                                                                          ||
||  logs:CreateLogStream                                                                         ||
||  logs:PutLogEvents                                                                            ||
|+-----------------------------------------------------------------------------------------------+|
|                                          GetRolePolicy                                          |
+-----------------+-------------------------------------------------------------------------------+
|  Resource       |  arn:aws:sqs:us-east-1:000000000000:ingest-events                             |
|  Sid            |  SqsConsume                                                                   |
+-----------------+-------------------------------------------------------------------------------+
||                                            Action                                             ||
|+-----------------------------------------------------------------------------------------------+|
||  sqs:ReceiveMessage                                                                           ||
||  sqs:DeleteMessage                                                                            ||
||  sqs:GetQueueAttributes                                                                       ||
||  sqs:ChangeMessageVisibility                                                                  ||
|+-----------------------------------------------------------------------------------------------+|
|                                          GetRolePolicy                                          |
+---------------------+---------------------------------------------------------------------------+
|  Resource           |  arn:aws:s3:::ingest-source-bucket/*                                      |
|  Sid                |  S3ReadSource                                                             |
+---------------------+---------------------------------------------------------------------------+
||                                            Action                                             ||
|+-----------------------------------------------------------------------------------------------+|
||  s3:GetObject                                                                                 ||
|+-----------------------------------------------------------------------------------------------+|
|                                          GetRolePolicy                                          |
+----------------------+--------------------------------------------------------------------------+
|  Resource            |  arn:aws:s3:::ingest-dest-bucket/*                                       |
|  Sid                 |  S3WriteDest                                                             |
+----------------------+--------------------------------------------------------------------------+
||                                            Action                                             ||
|+-----------------------------------------------------------------------------------------------+|
||  s3:PutObject                                                                                 ||
|+-----------------------------------------------------------------------------------------------+|
|                                          GetRolePolicy                                          |
+------------+------------------------------------------------------------------------------------+
|  Resource  |  arn:aws:dynamodb:us-east-1:000000000000:table/image-ingest-records                |
|  Sid       |  DynamoDbWrite                                                                     |
+------------+------------------------------------------------------------------------------------+
||                                            Action                                             ||
|+-----------------------------------------------------------------------------------------------+|
||  dynamodb:PutItem                                                                             ||
|+-----------------------------------------------------------------------------------------------+|
|                                          GetRolePolicy                                          |
+-----------+-------------------------------------------------------------------------------------+
|  Resource |  arn:aws:kms:us-east-1:000000000000:key/01e19618-85fe-4b8a-ba8e-ae264ef6da06        |
|  Sid      |  KmsDecryptSqs                                                                      |
+-----------+-------------------------------------------------------------------------------------+
||                                            Action                                             ||
|+-----------------------------------------------------------------------------------------------+|
||  kms:Decrypt                                                                                  ||
||  kms:GenerateDataKey                                                                          ||
||  kms:DescribeKey                                                                              ||
|+-----------------------------------------------------------------------------------------------+|
|                                          GetRolePolicy                                          |
+-----------+-------------------------------------------------------------------------------------+
|  Resource |  arn:aws:kms:us-east-1:000000000000:key/5252f602-5046-4ebf-9608-9983b03bd1f1        |
|  Sid      |  KmsDecryptSourceBucket                                                             |
+-----------+-------------------------------------------------------------------------------------+
||                                            Action                                             ||
|+-----------------------------------------------------------------------------------------------+|
||  kms:Decrypt                                                                                  ||
||  kms:DescribeKey                                                                              ||
|+-----------------------------------------------------------------------------------------------+|
|                                          GetRolePolicy                                          |
+-----------+-------------------------------------------------------------------------------------+
|  Resource |  arn:aws:kms:us-east-1:000000000000:key/f18a024a-ce55-4553-bb1d-d4c430bc0db3        |
|  Sid      |  KmsEncryptDestBucket                                                               |
+-----------+-------------------------------------------------------------------------------------+
||                                            Action                                             ||
|+-----------------------------------------------------------------------------------------------+|
||  kms:Encrypt                                                                                  ||
||  kms:Decrypt                                                                                  ||
||  kms:GenerateDataKey                                                                          ||
||  kms:DescribeKey                                                                              ||
|+-----------------------------------------------------------------------------------------------+|

write · /app/build/handler.py

import json
import logging
import os
import time
from urllib.parse import unquote_plus

import boto3

logger = logging.getLogger()
logger.setLevel(logging.INFO)

DEST_BUCKET = os.environ["DEST_BUCKET"]
DDB_TABLE = os.environ["DDB_TABLE"]
DEST_KMS_KEY = os.environ["DEST_KMS_KEY_ARN"]

_endpoint = os.environ.get("AWS_ENDPOINT_URL")
_kw = {"endpoint_url": _endpoint} if _endpoint else {}
s3 = boto3.client("s3", **_kw)
ddb = boto3.client("dynamodb", **_kw)


def _process_record(record):
    body = json.loads(record["body"])
    # S3 notification wraps the events in a "Records" array.
    s3_records = body.get("Records") or []
    if not s3_records:
        raise ValueError("no S3 Records in message body")

    for r in s3_records:
        src_bucket = r["s3"]["bucket"]["name"]
        # S3 event keys are URL-encoded (spaces -> "+"), must unquote_plus.
        raw_key = r["s3"]["object"]["key"]
        object_key = unquote_plus(raw_key)

        obj = s3.get_object(Bucket=src_bucket, Key=object_key)
        body_bytes = obj["Body"].read()
        source_size = len(body_bytes)

        dest_key = f"processed/{object_key}"
        s3.put_object(
            Bucket=DEST_BUCKET,
            Key=dest_key,
            Body=body_bytes,
            ServerSideEncryption="aws:kms",
            SSEKMSKeyId=DEST_KMS_KEY,
        )

        ddb.put_item(
            TableName=DDB_TABLE,
            Item={
                "object_key": {"S": object_key},
                "source_size": {"N": str(source_size)},
                "processed_at": {"S": str(int(time.time()))},
                "status": {"S": "OK"},
            },
        )


def lambda_handler(event, context):
    failures = []
    for record in event.get("Records", []):
        message_id = record.get("messageId")
        try:
            _process_record(record)
        except Exception as exc:
            logger.exception("failed to process messageId=%s: %s", message_id, exc)
            failures.append({"itemIdentifier": message_id})
    return {"batchItemFailures": failures}

Package lambda

shell

set -e
cd /app/build
rm -f handler.zip
zip -j handler.zip handler.py >/dev/null
ls -la handler.zip

output

-rw-r--r-- 1 root root 1066 Apr 22 09:32 handler.zip

[stdout]
-rw-r--r-- 1 root root 1066 Apr 22 09:32 handler.zip

Create 3 KMS CMKs with aliases
Create DynamoDB table image-ingest-records
Create source and dest S3 buckets with SSE-KMS
Create DLQ and main SQS queue with SSE-KMS + redrive
Set SQS queue policy to allow S3 SendMessage
Configure S3 bucket notification to SQS
Create Lambda IAM role with least-privilege inline policy
Write Lambda handler with partial batch failure support
Package and deploy Lambda; create event source mapping with ReportBatchItemFailures
Run end-to-end tests (happy path, space in key, batch partial failure)

Create Lambda function

shell

set -e
DST_KEY_ID=$(cat /app/build/dst_key_id)
DST_KEY_ARN="arn:aws:kms:us-east-1:000000000000:key/${DST_KEY_ID}"

aws lambda create-function \
  --function-name image-ingest-consumer \
  --runtime python3.11 \
  --role arn:aws:iam::000000000000:role/image-ingest-lambda-role \
  --handler handler.lambda_handler \
  --zip-file fileb:///app/build/handler.zip \
  --timeout 30 \
  --memory-size 256 \
  --environment "Variables={DEST_BUCKET=ingest-dest-bucket,DDB_TABLE=image-ingest-records,DEST_KMS_KEY_ARN=${DST_KEY_ARN},AWS_ENDPOINT_URL=http://localstack:4566}" \
  --query 'FunctionArn' --output text

output

arn:aws:lambda:us-east-1:000000000000:function:image-ingest-consumer

[stdout]
arn:aws:lambda:us-east-1:000000000000:function:image-ingest-consumer

Wait for lambda active

shell

set -e
aws lambda wait function-active --function-name image-ingest-consumer
aws lambda get-function --function-name image-ingest-consumer --query 'Configuration.State' --output text

output

Active

[stdout]
Active

Create event source mapping with ReportBatchItemFailures

shell

set -e
MAIN_ARN=$(cat /app/build/main_arn)
aws lambda create-event-source-mapping \
  --function-name image-ingest-consumer \
  --event-source-arn "$MAIN_ARN" \
  --batch-size 10 \
  --function-response-types ReportBatchItemFailures \
  --query '{UUID:UUID,State:State,ResponseTypes:FunctionResponseTypes}' --output table

# wait a moment for it to become enabled
sleep 2
aws lambda list-event-source-mappings --function-name image-ingest-consumer --query 'EventSourceMappings[].{State:State,ResponseTypes:FunctionResponseTypes,BatchSize:BatchSize}' --output table

output

------------------------------------------------------
|              CreateEventSourceMapping              |
+----------+-----------------------------------------+
|   State  |                  UUID                   |
+----------+-----------------------------------------+
|  Creating|  0c687baf-c256-472f-bea5-669b6d90dd48   |
+----------+-----------------------------------------+
||                   ResponseTypes                  ||
|+--------------------------------------------------+|
||  ReportBatchItemFailures                         ||
|+--------------------------------------------------+|
-------------------------------
|   ListEventSourceMappings   |
+---------------+-------------+
|   BatchSize   |    State    |
+---------------+-------------+
|  10           |  Enabled    |
+---------------+-------------+
||       ResponseTypes       ||
|+---------------------------+|
||  ReportBatchItemFailures  ||
|+---------------------------+|

[stdout]
------------------------------------------------------
|              CreateEventSourceMapping              |
+----------+-----------------------------------------+
|   State  |                  UUID                   |
+----------+-----------------------------------------+
|  Creating|  0c687baf-c256-472f-bea5-669b6d90dd48   |
+----------+-----------------------------------------+
||                   ResponseTypes                  ||
|+--------------------------------------------------+|
||  ReportBatchItemFailures                         ||
|+--------------------------------------------------+|
-------------------------------
|   ListEventSourceMappings   |
+---------------+-------------+
|   BatchSize   |    State    |
+---------------+-------------+
|  10           |  Enabled    |
+---------------+-------------+
||       ResponseTypes       ||
|+---------------------------+|
||  ReportBatchItemFailures  ||
|+---------------------------+|

Create 3 KMS CMKs with aliases
Create DynamoDB table image-ingest-records
Create source and dest S3 buckets with SSE-KMS
Create DLQ and main SQS queue with SSE-KMS + redrive
Set SQS queue policy to allow S3 SendMessage
Configure S3 bucket notification to SQS
Create Lambda IAM role with least-privilege inline policy
Write Lambda handler with partial batch failure support
Package and deploy Lambda; create event source mapping with ReportBatchItemFailures
Run end-to-end tests (happy path, space in key, batch partial failure)

Upload test objects including one with space

shell

set -e
mkdir -p /tmp/ingest_test
echo "hello world $(date +%s)" > /tmp/ingest_test/simple.txt
echo "has a space in it $(date +%s)" > "/tmp/ingest_test/with space.txt"

# Upload simple
aws s3api put-object --bucket ingest-source-bucket --key "simple.txt" --body /tmp/ingest_test/simple.txt --query 'ETag'
# Upload with space
aws s3api put-object --bucket ingest-source-bucket --key "folder/with space.txt" --body "/tmp/ingest_test/with space.txt" --query 'ETag'

echo "--- source bucket listing ---"
aws s3api list-objects-v2 --bucket ingest-source-bucket --query 'Contents[].Key'

output

"\"218972b43e950f7b3315f1b0b0288ab6\""
"\"b77b7ae0e1a6fb3b6d5cb87229a98531\""
--- source bucket listing ---
[
    "folder/with space.txt",
    "simple.txt"
]

[stdout]
"\"218972b43e950f7b3315f1b0b0288ab6\""
"\"b77b7ae0e1a6fb3b6d5cb87229a98531\""
--- source bucket listing ---
[
    "folder/with space.txt",
    "simple.txt"
]

Wait and check pipeline results

shell

sleep 8
echo "--- main queue ---"
aws sqs get-queue-attributes --queue-url "$(cat /app/build/main_url)" --attribute-names ApproximateNumberOfMessages ApproximateNumberOfMessagesNotVisible --query 'Attributes'
echo "--- DLQ ---"
aws sqs get-queue-attributes --queue-url "$(cat /app/build/dlq_url)" --attribute-names ApproximateNumberOfMessages --query 'Attributes'
echo "--- dest listing ---"
aws s3api list-objects-v2 --bucket ingest-dest-bucket --query 'Contents[].{Key:Key,Size:Size}'
echo "--- ddb scan ---"
aws dynamodb scan --table-name image-ingest-records --query 'Items[].{object_key:object_key.S,source_size:source_size.N,status:status.S}'

output

--- main queue ---
{
    "ApproximateNumberOfMessages": "0",
    "ApproximateNumberOfMessagesNotVisible": "1"
}
--- DLQ ---
{
    "ApproximateNumberOfMessages": "0"
}
--- dest listing ---
[
    {
        "Key": "processed/folder/with space.txt",
        "Size": 29
    },
    {
        "Key": "processed/simple.txt",
        "Size": 23
    }
]
--- ddb scan ---
[
    {
        "object_key": "folder/with space.txt",
        "source_size": "29",
        "status": "OK"
    },
    {
        "object_key": "simple.txt",
        "source_size": "23",
        "status": "OK"
    }
]

[stdout]
--- main queue ---
{
    "ApproximateNumberOfMessages": "0",
    "ApproximateNumberOfMessagesNotVisible": "1"
}
--- DLQ ---
{
    "ApproximateNumberOfMessages": "0"
}
--- dest listing ---
[
    {
        "Key": "processed/folder/with space.txt",
        "Size": 29
    },
    {
        "Key": "processed/simple.txt",
        "Size": 23
    }
]
--- ddb scan ---
[
    {
        "object_key": "folder/with space.txt",
        "source_size": "29",
        "status": "OK"
    },
    {
        "object_key": "simple.txt",
        "source_size": "23",
        "status": "OK"
    }
]

Happy path works , both keys (including the one with a space) appear in `processed/`, two DDB rows, DLQ empty. Now test partial batch failure with a direct lambda invoke.

write · /app/build/partial_batch_event.json

{
  "Records": [
    {
      "messageId": "msg-good-0001",
      "receiptHandle": "rh-good",
      "body": "{\"Records\":[{\"s3\":{\"bucket\":{\"name\":\"ingest-source-bucket\"},\"object\":{\"key\":\"simple.txt\"}}}]}",
      "attributes": {},
      "messageAttributes": {},
      "md5OfBody": "",
      "eventSource": "aws:sqs",
      "eventSourceARN": "arn:aws:sqs:us-east-1:000000000000:ingest-events",
      "awsRegion": "us-east-1"
    },
    {
      "messageId": "msg-bad-0002",
      "receiptHandle": "rh-bad",
      "body": "this is not json at all",
      "attributes": {},
      "messageAttributes": {},
      "md5OfBody": "",
      "eventSource": "aws:sqs",
      "eventSourceARN": "arn:aws:sqs:us-east-1:000000000000:ingest-events",
      "awsRegion": "us-east-1"
    }
  ]
}

Invoke lambda with mixed good+bad batch

shell

set -e
rm -f /tmp/lambda_out.json
aws lambda invoke --function-name image-ingest-consumer \
  --payload fileb:///app/build/partial_batch_event.json \
  --cli-binary-format raw-in-base64-out \
  /tmp/lambda_out.json --query 'StatusCode'
echo "--- response ---"
cat /tmp/lambda_out.json
echo

output

200
--- response ---
{"batchItemFailures": [{"itemIdentifier": "msg-bad-0002"}]}

[stdout]
200
--- response ---
{"batchItemFailures": [{"itemIdentifier": "msg-bad-0002"}]}

Final verification

shell

echo "--- final check: DLQ ---"
aws sqs get-queue-attributes --queue-url "$(cat /app/build/dlq_url)" --attribute-names ApproximateNumberOfMessages --query 'Attributes'
echo "--- final check: main queue ---"
aws sqs get-queue-attributes --queue-url "$(cat /app/build/main_url)" --attribute-names ApproximateNumberOfMessages ApproximateNumberOfMessagesNotVisible --query 'Attributes'
echo "--- dest objects ---"
aws s3api list-objects-v2 --bucket ingest-dest-bucket --query 'Contents[].Key'
echo "--- ddb rows ---"
aws dynamodb scan --table-name image-ingest-records --query 'Items[].{object_key:object_key.S,source_size:source_size.N,status:status.S,processed_at:processed_at.S}'

output

--- final check: DLQ ---
{
    "ApproximateNumberOfMessages": "0"
}
--- final check: main queue ---
{
    "ApproximateNumberOfMessages": "0",
    "ApproximateNumberOfMessagesNotVisible": "1"
}
--- dest objects ---
[
    "processed/folder/with space.txt",
    "processed/simple.txt"
]
--- ddb rows ---
[
    {
        "object_key": "folder/with space.txt",
        "source_size": "29",
        "status": "OK",
        "processed_at": "1776850429"
    },
    {
        "object_key": "simple.txt",
        "source_size": "23",
        "status": "OK",
        "processed_at": "1776850458"
    }
]

[stdout]
--- final check: DLQ ---
{
    "ApproximateNumberOfMessages": "0"
}
--- final check: main queue ---
{
    "ApproximateNumberOfMessages": "0",
    "ApproximateNumberOfMessagesNotVisible": "1"
}
--- dest objects ---
[
    "processed/folder/with space.txt",
    "processed/simple.txt"
]
--- ddb rows ---
[
    {
        "object_key": "folder/with space.txt",
        "source_size": "29",
        "status": "OK",
        "processed_at": "1776850429"
    },
    {
        "object_key": "simple.txt",
        "source_size": "23",
        "status": "OK",
        "processed_at": "1776850458"
    }
]

Verify queues drain and nothing lands in DLQ

shell

sleep 25
echo "--- after waiting 25s ---"
aws sqs get-queue-attributes --queue-url "$(cat /app/build/main_url)" --attribute-names ApproximateNumberOfMessages ApproximateNumberOfMessagesNotVisible --query 'Attributes'
echo "--- DLQ ---"
aws sqs get-queue-attributes --queue-url "$(cat /app/build/dlq_url)" --attribute-names ApproximateNumberOfMessages --query 'Attributes'

output

<tool_use_error>Blocked: sleep 25 followed by: echo "--- after waiting 25s ---" aws sqs get-queue-attributes --queue-url "$(cat /app/build/main_url)" --attribute-names ApproximateNumberOfMessages ApproximateNumberOfMessagesNotVisible --query 'Attributes' echo "--- DLQ ---" aws sqs get-queue-attributes --queue-url "$(cat /app/build/dlq_url)" --attribute-names ApproximateNumberOfMessages --query 'Attributes'. To wait for a condition, use Monitor with an until-loop (e.g. `until <check>; do sleep 2; done`). To wait for a command you started, use run_in_background: true. Do not chain shorter sleeps to work around this block.</tool_use_error>

[error] tool reported failure

Wait for in-flight to clear, check DLQ

shell

until [ "$(aws sqs get-queue-attributes --queue-url "$(cat /app/build/main_url)" --attribute-names ApproximateNumberOfMessagesNotVisible --query 'Attributes.ApproximateNumberOfMessagesNotVisible' --output text)" = "0" ]; do sleep 3; done
echo "drained"
aws sqs get-queue-attributes --queue-url "$(cat /app/build/main_url)" --attribute-names ApproximateNumberOfMessages ApproximateNumberOfMessagesNotVisible --query 'Attributes'
echo "--- DLQ ---"
aws sqs get-queue-attributes --queue-url "$(cat /app/build/dlq_url)" --attribute-names ApproximateNumberOfMessages --query 'Attributes'

output

drained
{
    "ApproximateNumberOfMessages": "0",
    "ApproximateNumberOfMessagesNotVisible": "1"
}
--- DLQ ---
{
    "ApproximateNumberOfMessages": "0"
}

[stdout]
drained
{
    "ApproximateNumberOfMessages": "0",
    "ApproximateNumberOfMessagesNotVisible": "1"
}
--- DLQ ---
{
    "ApproximateNumberOfMessages": "0"
}

Poll queue attributes over time

shell

for i in 1 2 3 4 5; do
  ATTRS=$(aws sqs get-queue-attributes --queue-url "$(cat /app/build/main_url)" --attribute-names ApproximateNumberOfMessages ApproximateNumberOfMessagesNotVisible --query 'Attributes' --output json)
  echo "poll $i: $ATTRS"
  sleep 5
done
echo "--- DLQ ---"
aws sqs get-queue-attributes --queue-url "$(cat /app/build/dlq_url)" --attribute-names ApproximateNumberOfMessages --query 'Attributes'

output

poll 1: {
    "ApproximateNumberOfMessages": "0",
    "ApproximateNumberOfMessagesNotVisible": "1"
}
poll 2: {
    "ApproximateNumberOfMessages": "0",
    "ApproximateNumberOfMessagesNotVisible": "1"
}
poll 3: {
    "ApproximateNumberOfMessages": "0",
    "ApproximateNumberOfMessagesNotVisible": "1"
}
poll 4: {
    "ApproximateNumberOfMessages": "0",
    "ApproximateNumberOfMessagesNotVisible": "1"
}
poll 5: {
    "ApproximateNumberOfMessages": "0",
    "ApproximateNumberOfMessagesNotVisible": "1"
}
--- DLQ ---
{
    "ApproximateNumberOfMessages": "0"
}

[stdout]
poll 1: {
    "ApproximateNumberOfMessages": "0",
    "ApproximateNumberOfMessagesNotVisible": "1"
}
poll 2: {
    "ApproximateNumberOfMessages": "0",
    "ApproximateNumberOfMessagesNotVisible": "1"
}
poll 3: {
    "ApproximateNumberOfMessages": "0",
    "ApproximateNumberOfMessagesNotVisible": "1"
}
poll 4: {
    "ApproximateNumberOfMessages": "0",
    "ApproximateNumberOfMessagesNotVisible": "1"
}
poll 5: {
    "ApproximateNumberOfMessages": "0",
    "ApproximateNumberOfMessagesNotVisible": "1"
}
--- DLQ ---
{
    "ApproximateNumberOfMessages": "0"
}

Get latest lambda log stream

shell

aws logs describe-log-streams --log-group-name /aws/lambda/image-ingest-consumer --order-by LastEventTime --descending --max-items 1 --query 'logStreams[0].logStreamName' --output text 2>&1 | head -1

output

2026/04/22/[$LATEST]44c04e6482390cc7180a25ebe221e496

[stdout]
2026/04/22/[$LATEST]44c04e6482390cc7180a25ebe221e496

Tail lambda logs

shell

aws logs tail /aws/lambda/image-ingest-consumer --since 3m --format short 2>&1 | tail -40

output

2026-04-22T09:33:31 Traceback (most recent call last):
2026-04-22T09:33:31   File "/var/task/handler.py", line 64, in lambda_handler
2026-04-22T09:33:31     _process_record(record)
2026-04-22T09:33:31   File "/var/task/handler.py", line 27, in _process_record
2026-04-22T09:33:31     raise ValueError("no S3 Records in message body")
2026-04-22T09:33:31 ValueError: no S3 Records in message bodyEND RequestId: 28e9eeb2-3953-4912-9e9b-cd2ce162fa4a
2026-04-22T09:33:31 REPORT RequestId: 28e9eeb2-3953-4912-9e9b-cd2ce162fa4a	Duration: 11.64 ms	Billed Duration: 12 ms	Memory Size: 256 MB	Max Memory Used: 256 MB
2026-04-22T09:33:49 [INFO]	2026-04-22T09:33:48.790Z		Found credentials in environment variables.
2026-04-22T09:33:49 START RequestId: 49c9b000-4ba4-4ecb-82ec-d9588873cd07 Version: $LATEST
2026-04-22T09:33:49 END RequestId: 49c9b000-4ba4-4ecb-82ec-d9588873cd07
2026-04-22T09:33:49 REPORT RequestId: 49c9b000-4ba4-4ecb-82ec-d9588873cd07	Duration: 153.56 ms	Billed Duration: 154 ms	Memory Size: 256 MB	Max Memory Used: 256 MB
2026-04-22T09:34:18 [INFO]	2026-04-22T09:34:17.783Z		Found credentials in environment variables.
2026-04-22T09:34:18 START RequestId: c29ecb57-bb89-4d24-bc61-886f7c180e0f Version: $LATEST
2026-04-22T09:34:18 [ERROR]	2026-04-22T09:34:18.173Z	c29ecb57-bb89-4d24-bc61-886f7c180e0f	failed to process messageId=msg-bad-0002: Expecting value: line 1 column 1 (char 0)
2026-04-22T09:34:18 Traceback (most recent call last):
2026-04-22T09:34:18   File "/var/task/handler.py", line 64, in lambda_handler
2026-04-22T09:34:18     _process_record(record)
2026-04-22T09:34:18   File "/var/task/handler.py", line 23, in _process_record
2026-04-22T09:34:18     body = json.loads(record["body"])
2026-04-22T09:34:18            ^^^^^^^^^^^^^^^^^^^^^^^^^^
2026-04-22T09:34:18   File "/var/lang/lib/python3.11/json/__init__.py", line 346, in loads
2026-04-22T09:34:18     return _default_decoder.decode(s)
2026-04-22T09:34:18            ^^^^^^^^^^^^^^^^^^^^^^^^^^
2026-04-22T09:34:18   File "/var/lang/lib/python3.11/json/decoder.py", line 337, in decode
2026-04-22T09:34:18     obj, end = self.raw_decode(s, idx=_w(s, 0).end())
2026-04-22T09:34:18                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
2026-04-22T09:34:18   File "/var/lang/lib/python3.11/json/decoder.py", line 355, in raw_decode
2026-04-22T09:34:18     raise JSONDecodeError("Expecting value", s, err.value) from None
2026-04-22T09:34:18 json.decoder.JSONDecodeError: Expecting value: line 1 column 1 (char 0)END RequestId: c29ecb57-bb89-4d24-bc61-886f7c180e0f
2026-04-22T09:34:18 REPORT RequestId: c29ecb57-bb89-4d24-bc61-886f7c180e0f	Duration: 83.21 ms	Billed Duration: 84 ms	Memory Size: 256 MB	Max Memory Used: 256 MB
2026-04-22T09:35:03 [INFO]	2026-04-22T09:35:03.319Z		Found credentials in environment variables.
2026-04-22T09:35:03 START RequestId: 1748e3b8-97b6-4754-9da1-b1d51065eaa8 Version: $LATEST
2026-04-22T09:35:03 [ERROR]	2026-04-22T09:35:03.632Z	1748e3b8-97b6-4754-9da1-b1d51065eaa8	failed to process messageId=2d90eb3a-5074-4724-a5da-a9c0ba9887fd: no S3 Records in message body
2026-04-22T09:35:03 Traceback (most recent call last):
2026-04-22T09:35:03   File "/var/task/handler.py", line 64, in lambda_handler
2026-04-22T09:35:03     _process_record(record)
2026-04-22T09:35:03   File "/var/task/handler.py", line 27, in _process_record
2026-04-22T09:35:03     raise ValueError("no S3 Records in message body")
2026-04-22T09:35:03 ValueError: no S3 Records in message bodyEND RequestId: 1748e3b8-97b6-4754-9da1-b1d51065eaa8
2026-04-22T09:35:03 REPORT RequestId: 1748e3b8-97b6-4754-9da1-b1d51065eaa8	Duration: 11.05 ms	Billed Duration: 12 ms	Memory Size: 256 MB	Max Memory Used: 256 MB

[stdout]
2026-04-22T09:33:31 Traceback (most recent call last):
2026-04-22T09:33:31   File "/var/task/handler.py", line 64, in lambda_handler
2026-04-22T09:33:31     _process_record(record)
2026-04-22T09:33:31   File "/var/task/handler.py", line 27, in _process_record
2026-04-22T09:33:31     raise ValueError("no S3 Records in message body")
2026-04-22T09:33:31 ValueError: no S3 Records in message bodyEND RequestId: 28e9eeb2-3953-4912-9e9b-cd2ce162fa4a
2026-04-22T09:33:31 REPORT RequestId: 28e9eeb2-3953-4912-9e9b-cd2ce162fa4a	Duration: 11.64 ms	Billed Duration: 12 ms	Memory Size: 256 MB	Max Memory Used: 256 MB
2026-04-22T09:33:49 [INFO]	2026-04-22T09:33:48.790Z		Found credentials in environment variables.
2026-04-22T09:33:49 START RequestId: 49c9b000-4ba4-4ecb-82ec-d9588873cd07 Version: $LATEST
2026-04-22T09:33:49 END RequestId: 49c9b000-4ba4-4ecb-82ec-d9588873cd07
2026-04-22T09:33:49 REPORT RequestId: 49c9b000-4ba4-4ecb-82ec-d9588873cd07	Duration: 153.56 ms	Billed Duration: 154 ms	Memory Size: 256 MB	Max Memory Used: 256 MB
2026-04-22T09:34:18 [INFO]	2026-04-22T09:34:17.783Z		Found credentials in environment variables.
2026-04-22T09:34:18 START RequestId: c29ecb57-bb89-4d24-bc61-886f7c180e0f Version: $LATEST
2026-04-22T09:34:18 [ERROR]	2026-04-22T09:34:18.173Z	c29ecb57-bb89-4d24-bc61-886f7c180e0f	failed to process messageId=msg-bad-0002: Expecting value: line 1 column 1 (char 0)
2026-04-22T09:34:18 Traceback (most recent call last):
2026-04-22T09:34:18   File "/var/task/handler.py", line 64, in lambda_handler
2026-04-22T09:34:18     _process_record(record)
2026-04-22T09:34:18   File "/var/task/handler.py", line 23, in _process_record
2026-04-22T09:34:18     body = json.loads(record["body"])
2026-04-22T09:34:18            ^^^^^^^^^^^^^^^^^^^^^^^^^^
2026-04-22T09:34:18   File "/var/lang/lib/python3.11/json/__init__.py", line 346, in loads
2026-04-22T09:34:18     return _default_decoder.decode(s)
2026-04-22T09:34:18            ^^^^^^^^^^^^^^^^^^^^^^^^^^
2026-04-22T09:34:18   File "/var/lang/lib/python3.11/json/decoder.py", line 337, in decode
2026-04-22T09:34:18     obj, end = self.raw_decode(s, idx=_w(s, 0).end())
2026-04-22T09:34:18                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
2026-04-22T09:34:18   File "/var/lang/lib/python3.11/json/decoder.py", line 355, in raw_decode
2026-04-22T09:34:18     raise JSONDecodeError("Expecting value", s, err.value) from None
2026-04-22T09:34:18 json.decoder.JSONDecodeError: Expecting value: line 1 column 1 (char 0)END RequestId: c29ecb57-bb89-4d24-bc61-886f7c180e0f
2026-04-22T09:34:18 REPORT RequestId: c29ecb57-bb89-4d24-bc61-886f7c180e0f	Duration: 83.21 ms	Billed Duration: 84 ms	Memory Size: 256 MB	Max Memory Used: 256 MB
2026-04-22T09:35:03 [INFO]	2026-04-22T09:35:03.319Z		Found credentials in environment variables.
2026-04-22T09:35:03 START RequestId: 1748e3b8-97b6-4754-9da1-b1d51065eaa8 Version: $LATEST
2026-04-22T09:35:03 [ERROR]	2026-04-22T09:35:03.632Z	1748e3b8-97b6-4754-9da1-b1d51065eaa8	failed to process messageId=2d90eb3a-5074-4724-a5da-a9c0ba9887fd: no S3 Records in message body
2026-04-22T09:35:03 Traceback (most recent call last):
2026-04-22T09:35:03   File "/var/task/handler.py", line 64, in lambda_handler
2026-04-22T09:35:03     _process_record(record)
2026-04-22T09:35:03   File "/var/task/handler.py", line 27, in _process_record
2026-04-22T09:35:03     raise ValueError("no S3 Records in message body")
2026-04-22T09:35:03 ValueError: no S3 Records in message bodyEND RequestId: 1748e3b8-97b6-4754-9da1-b1d51065eaa8
2026-04-22T09:35:03 REPORT RequestId: 1748e3b8-97b6-4754-9da1-b1d51065eaa8	Duration: 11.05 ms	Billed Duration: 12 ms	Memory Size: 256 MB	Max Memory Used: 256 MB

There's a leftover unparseable message in the main queue from earlier testing , it'll eventually hit maxReceiveCount and land in the DLQ. Let me purge both queues and the existing data, then verify with a clean end-to-end run.

Purge queues and test artifacts

shell

set -e
# Purge queues
aws sqs purge-queue --queue-url "$(cat /app/build/main_url)"
aws sqs purge-queue --queue-url "$(cat /app/build/dlq_url)"

# Clean up dest bucket and ddb from earlier test
aws s3api list-objects-v2 --bucket ingest-dest-bucket --query 'Contents[].Key' --output text | tr '\t' '\n' | while read k; do
  [ -n "$k" ] && aws s3api delete-object --bucket ingest-dest-bucket --key "$k" >/dev/null
done
aws s3api list-objects-v2 --bucket ingest-source-bucket --query 'Contents[].Key' --output text | tr '\t' '\n' | while read k; do
  [ -n "$k" ] && aws s3api delete-object --bucket ingest-source-bucket --key "$k" >/dev/null
done
aws dynamodb scan --table-name image-ingest-records --query 'Items[].object_key.S' --output text | tr '\t' '\n' | while read k; do
  [ -n "$k" ] && aws dynamodb delete-item --table-name image-ingest-records --key "{\"object_key\":{\"S\":\"$k\"}}"
done

echo "--- post-clean state ---"
aws s3api list-objects-v2 --bucket ingest-source-bucket --query 'Contents' --output text
aws s3api list-objects-v2 --bucket ingest-dest-bucket --query 'Contents' --output text
aws dynamodb scan --table-name image-ingest-records --query 'Count'
aws sqs get-queue-attributes --queue-url "$(cat /app/build/main_url)" --attribute-names ApproximateNumberOfMessages ApproximateNumberOfMessagesNotVisible --query 'Attributes'
aws sqs get-queue-attributes --queue-url "$(cat /app/build/dlq_url)" --attribute-names ApproximateNumberOfMessages --query 'Attributes'

output

--- post-clean state ---
None
None
0
{
    "ApproximateNumberOfMessages": "0",
    "ApproximateNumberOfMessagesNotVisible": "0"
}
{
    "ApproximateNumberOfMessages": "0"
}

[stdout]
--- post-clean state ---
None
None
0
{
    "ApproximateNumberOfMessages": "0",
    "ApproximateNumberOfMessagesNotVisible": "0"
}
{
    "ApproximateNumberOfMessages": "0"
}

Clean slate. Now verify the full pipeline with a single PUT, including the spaces-in-key case.

PUT test objects

shell

set -e
echo "payload-$(date +%s)" > /tmp/ingest_test/verify.txt
echo "payload-with-space-$(date +%s)" > "/tmp/ingest_test/verify space.txt"
aws s3api put-object --bucket ingest-source-bucket --key "verify.txt" --body /tmp/ingest_test/verify.txt >/dev/null
aws s3api put-object --bucket ingest-source-bucket --key "a/b/verify space.txt" --body "/tmp/ingest_test/verify space.txt" >/dev/null
date +%s

output

1776850585

[stdout]
1776850585

Verify end-to-end results

shell

until [ "$(aws dynamodb scan --table-name image-ingest-records --query 'Count' --output text)" = "2" ]; do sleep 2; done
echo "both rows present"
echo "--- dest objects ---"
aws s3api list-objects-v2 --bucket ingest-dest-bucket --query 'Contents[].Key'
echo "--- ddb ---"
aws dynamodb scan --table-name image-ingest-records --query 'Items[].{object_key:object_key.S,size:source_size.N,status:status.S}'
echo "--- DLQ ---"
aws sqs get-queue-attributes --queue-url "$(cat /app/build/dlq_url)" --attribute-names ApproximateNumberOfMessages --query 'Attributes'

output

both rows present
--- dest objects ---
[
    "processed/a/b/verify space.txt",
    "processed/verify.txt"
]
--- ddb ---
[
    {
        "object_key": "verify.txt",
        "size": "19",
        "status": "OK"
    },
    {
        "object_key": "a/b/verify space.txt",
        "size": "30",
        "status": "OK"
    }
]
--- DLQ ---
{
    "ApproximateNumberOfMessages": "0"
}

[stdout]
both rows present
--- dest objects ---
[
    "processed/a/b/verify space.txt",
    "processed/verify.txt"
]
--- ddb ---
[
    {
        "object_key": "verify.txt",
        "size": "19",
        "status": "OK"
    },
    {
        "object_key": "a/b/verify space.txt",
        "size": "30",
        "status": "OK"
    }
]
--- DLQ ---
{
    "ApproximateNumberOfMessages": "0"
}

Re-test partial batch failure

shell

rm -f /tmp/lambda_out.json
aws lambda invoke --function-name image-ingest-consumer \
  --payload fileb:///app/build/partial_batch_event.json \
  --cli-binary-format raw-in-base64-out \
  /tmp/lambda_out.json --query 'StatusCode' --output text
cat /tmp/lambda_out.json; echo

output

200
{"batchItemFailures": [{"itemIdentifier": "msg-good-0001"}, {"itemIdentifier": "msg-bad-0002"}]}

[stdout]
200
{"batchItemFailures": [{"itemIdentifier": "msg-good-0001"}, {"itemIdentifier": "msg-bad-0002"}]}

The "good" record in the test event pointed at `simple.txt` which I deleted during cleanup. Updating it to a current key.

write · /app/build/partial_batch_event.json

{
  "Records": [
    {
      "messageId": "msg-good-0001",
      "receiptHandle": "rh-good",
      "body": "{\"Records\":[{\"s3\":{\"bucket\":{\"name\":\"ingest-source-bucket\"},\"object\":{\"key\":\"verify.txt\"}}}]}",
      "attributes": {},
      "messageAttributes": {},
      "md5OfBody": "",
      "eventSource": "aws:sqs",
      "eventSourceARN": "arn:aws:sqs:us-east-1:000000000000:ingest-events",
      "awsRegion": "us-east-1"
    },
    {
      "messageId": "msg-bad-0002",
      "receiptHandle": "rh-bad",
      "body": "this is not json at all",
      "attributes": {},
      "messageAttributes": {},
      "md5OfBody": "",
      "eventSource": "aws:sqs",
      "eventSourceARN": "arn:aws:sqs:us-east-1:000000000000:ingest-events",
      "awsRegion": "us-east-1"
    }
  ]
}

Re-test partial batch with valid good key

shell

rm -f /tmp/lambda_out.json
aws lambda invoke --function-name image-ingest-consumer \
  --payload fileb:///app/build/partial_batch_event.json \
  --cli-binary-format raw-in-base64-out \
  /tmp/lambda_out.json --query 'StatusCode' --output text
cat /tmp/lambda_out.json; echo

output

200
{"batchItemFailures": [{"itemIdentifier": "msg-bad-0002"}]}

[stdout]
200
{"batchItemFailures": [{"itemIdentifier": "msg-bad-0002"}]}

Create 3 KMS CMKs with aliases
Create DynamoDB table image-ingest-records
Create source and dest S3 buckets with SSE-KMS
Create DLQ and main SQS queue with SSE-KMS + redrive
Set SQS queue policy to allow S3 SendMessage
Configure S3 bucket notification to SQS
Create Lambda IAM role with least-privilege inline policy
Write Lambda handler with partial batch failure support
Package and deploy Lambda; create event source mapping with ReportBatchItemFailures
Run end-to-end tests (happy path, space in key, batch partial failure)

All three test shapes pass. Final state summary below. **Pipeline stood up and verified end-to-end:** - **KMS** , 3 CMKs with aliases `alias/source-bucket-cmk`, `alias/sqs-queue-cmk`, `alias/dest-bucket-cmk`. Each key policy scoped to explicit principals (root + the specific service + the Lambda role ARN); no wildcards on principals or cross-boundary usage. - **S3** , `ingest-source-bucket` (SSE-KMS w/ source CMK) with `s3:ObjectCreated:*` → main queue. `ingest-dest-bucket` (SSE-KMS w/ dest CMK). - **SQS** , `ingest-events` (SSE-KMS w/ sqs CMK, visibility 90s > lambda timeout 30s, redrive to `ingest-dlq` after 3 receives). Queue resource policy allows `s3.amazonaws.com` to `SendMessage` only from the source bucket ARN + account. `ingest-dlq` also SSE-KMS with same sqs CMK. - **DynamoDB** , `image-ingest-records`, partition key `object_key` (S), PAY_PER_REQUEST. - **IAM** , `image-ingest-lambda-role` inline policy is per-resource: logs only on the function's log group, `sqs:*` actions only on `ingest-events`, `s3:GetObject` only on source, `s3:PutObject` only on dest, `dynamodb:PutItem` only on the table, and KMS split across the three key ARNs (Decrypt on source+sqs, Encrypt/Decrypt/GenerateDataKey on dest). - **Lambda** , `image-ingest-consumer` (python3.11, handler `handler.lambda_handler`), event source mapping has `FunctionResponseTypes=ReportBatchItemFailures`; handler unquote_plus's the S3 event key, wraps each record in try/except, and returns `{"batchItemFailures":[{"itemIdentifier": <messageId>},…]}`. **Verified:** - PUT `verify.txt` → `processed/verify.txt` in dest + DDB row, within seconds. - PUT `a/b/verify space.txt` → `processed/a/b/verify space.txt` with the space correctly decoded (the S3 event URL-encoded it to `+`). - DLQ stays at 0 messages. - Mixed-batch direct invoke returns exactly `{"batchItemFailures": [{"itemIdentifier": "msg-bad-0002"}]}` , only the broken record is reported, so the good record won't be retried. Build artifacts (policies, handler, ids) are under `/app/build/`.

Final diff , what the agent changed

No file changes, the agent left the workspace untouched.

Verifier output , the proof behind the reward

tests/test.sh

============================= test session starts ==============================
platform linux -- Python 3.12.3, pytest-8.4.1, pluggy-1.6.0 -- /root/.cache/uv/archive-v0/vNH6cQSfCkhmwP01DzbN4/bin/python
cachedir: .pytest_cache
rootdir: /tests
plugins: json-ctrf-0.3.5
collecting ... collected 18 items

../tests/test_outputs.py::test_aws_cli_binary_is_real PASSED             [  5%]
../tests/test_outputs.py::test_localstack_reachable PASSED               [ 11%]
../tests/test_outputs.py::test_source_and_dest_buckets_use_customer_cmks PASSED [ 16%]
../tests/test_outputs.py::test_main_queue_and_dlq_exist_and_are_encrypted PASSED [ 22%]
../tests/test_outputs.py::test_lambda_exists_with_expected_handler PASSED [ 27%]
../tests/test_outputs.py::test_ddb_table_exists PASSED                   [ 33%]
../tests/test_outputs.py::test_source_bucket_notification_targets_main_queue PASSED [ 38%]
../tests/test_outputs.py::test_main_queue_policy_allows_s3_service PASSED [ 44%]
../tests/test_outputs.py::test_sqs_cmk_allows_s3_service PASSED          [ 50%]
../tests/test_outputs.py::test_source_cmk_allows_lambda_role_decrypt PASSED [ 55%]
../tests/test_outputs.py::test_dest_cmk_allows_lambda_role_encrypt PASSED [ 61%]
../tests/test_outputs.py::test_lambda_role_has_kms_decrypt_on_sqs_cmk PASSED [ 66%]
../tests/test_outputs.py::test_main_queue_visibility_timeout_covers_lambda_timeout PASSED [ 72%]
../tests/test_outputs.py::test_event_source_mapping_declares_report_batch_item_failures PASSED [ 77%]
../tests/test_outputs.py::test_lambda_handler_returns_correct_response_shape PASSED [ 83%]
../tests/test_outputs.py::test_end_to_end_preserves_object_size PASSED   [ 88%]
../tests/test_outputs.py::test_end_to_end_key_with_spaces_is_decoded PASSED [ 94%]
../tests/test_outputs.py::test_end_to_end_upload_propagates_to_dest_and_ddb PASSED [100%]

=============================== warnings summary ===============================
test_outputs.py: 64 warnings
  /root/.cache/uv/archive-v0/vNH6cQSfCkhmwP01DzbN4/lib/python3.12/site-packages/botocore/auth.py:424: DeprecationWarning: datetime.datetime.utcnow() is deprecated and scheduled for removal in a future version. Use timezone-aware objects to represent datetimes in UTC: datetime.datetime.now(datetime.UTC).
    datetime_now = datetime.datetime.utcnow()

-- Docs: https://docs.pytest.org/en/stable/how-to/capture-warnings.html
==================================== PASSES ====================================
=========================== short test summary info ============================
PASSED ../tests/test_outputs.py::test_aws_cli_binary_is_real
PASSED ../tests/test_outputs.py::test_localstack_reachable
PASSED ../tests/test_outputs.py::test_source_and_dest_buckets_use_customer_cmks
PASSED ../tests/test_outputs.py::test_main_queue_and_dlq_exist_and_are_encrypted
PASSED ../tests/test_outputs.py::test_lambda_exists_with_expected_handler
PASSED ../tests/test_outputs.py::test_ddb_table_exists
PASSED ../tests/test_outputs.py::test_source_bucket_notification_targets_main_queue
PASSED ../tests/test_outputs.py::test_main_queue_policy_allows_s3_service
PASSED ../tests/test_outputs.py::test_sqs_cmk_allows_s3_service
PASSED ../tests/test_outputs.py::test_source_cmk_allows_lambda_role_decrypt
PASSED ../tests/test_outputs.py::test_dest_cmk_allows_lambda_role_encrypt
PASSED ../tests/test_outputs.py::test_lambda_role_has_kms_decrypt_on_sqs_cmk
PASSED ../tests/test_outputs.py::test_main_queue_visibility_timeout_covers_lambda_timeout
PASSED ../tests/test_outputs.py::test_event_source_mapping_declares_report_batch_item_failures
PASSED ../tests/test_outputs.py::test_lambda_handler_returns_correct_response_shape
PASSED ../tests/test_outputs.py::test_end_to_end_preserves_object_size
PASSED ../tests/test_outputs.py::test_end_to_end_key_with_spaces_is_decoded
PASSED ../tests/test_outputs.py::test_end_to_end_upload_propagates_to_dest_and_ddb
======================= 18 passed, 64 warnings in 14.10s =======================

Reproduce this trial: git checkout 2f94510 && PYTHONPATH=src python3 scripts/build_site.py , then open trial/trial_e4d732883a2f409b. Re-running the agent live requires EVAL_PLATFORM_ENABLE_OAUTH_SMOKE=1 and is non-deterministic.

Trial trial_e4d732883a2f409b · verifier authoritative; classifier explanatory.