aws logs tail: Stream CloudWatch Logs in CI

Tail or fetch recent CloudWatch Logs for a log group from the CLI.

aws logs tail prints recent CloudWatch Logs events for a group and can follow them live. In CI it surfaces Lambda, ECS, or application logs right after a deploy to verify behavior or capture failure output without opening the console.

Common flags

--follow - stream new events as they arrive
--since 10m - start from a relative time (e.g. 1h, 30m)
--filter-pattern "ERROR" - only show matching events
--format short - compact output without metadata

Example in CI

Pull the last 5 minutes of error logs after a deploy.

shell

aws logs tail /aws/lambda/my-api --since 5m --filter-pattern "ERROR"

Common errors in CI

An error occurred (ResourceNotFoundException) - log group does not exist yet
An error occurred (AccessDeniedException) - role lacks logs:GetLogEvents/FilterLogEvents
No output - events have not propagated yet, or --since window is too short

Key takeaways

aws logs tail fetches recent events; add --follow to stream live.
Use --since and --filter-pattern to scope a post-deploy log check in CI.
A missing log group (ResourceNotFoundException) usually means it has not been invoked yet.