CloudWatch

We use CloudWatch for:

• structured logs
• custom metrics via EMF (Embedded Metric Format)

Logs

Each Lambda writes JSON logs to:

• /aws/lambda/<FunctionName>

These logs support quick investigation in CloudWatch Logs Insights.

Metrics (EMF)

Namespace: PipelineInvestigationKit

Examples emitted by the functions:

• Ingest: IngestLagMs, DuplicateCount, IngestAcceptedCount
• Replay: ReplayRequestedCount, ReplayMessageCount
• Processor: ProcessorMessageCount, ProcessorErrorCount

Why EMF?

• No separate PutMetricData calls (cheaper/simpler).
• Metrics show up automatically from logs.
• Easy to build dashboards and alarms.

Next steps (for teams)

• Create alarms on error counts and lag percentiles.
• Add a dashboard grouping ingest/replay/processor metrics.