CI: run LocalStack via lstk instead of the localstack PyPI package

[silv-io]

Motivation

The release workflow installs localstack==${RELEASE_VERSION} from PyPI just to start LocalStack for the SDK tests. This couples the SDK release to the localstack package release (published separately via localstack-cli-standalone, with no retry on PyPI propagation lag) and stands in the way of the planned deprecation of that package. The pinned Docker image is the actual dependency; the pip package is only the launcher.

Changes

• release.yml: install lstk via npm instead of pip install localstack==$VERSION; pin the emulator image through an lstk config file in $RUNNER_TEMP (outside the workspace, so the "Check Uncommitted Changes" gate stays clean). lstk start --timeout 2m replaces start -d + wait — it blocks until the emulator is healthy and dumps startup logs itself on failure. logs/stop pass the same --config, since the derived container name embeds the pinned tag.
• test.yml: same swap, no config file needed — lstk defaults to localstack/localstack-pro:latest.
• DEBUG/DISABLE_EVENTS become LOCALSTACK_DEBUG/LOCALSTACK_DISABLE_EVENTS (lstk forwards LOCALSTACK_* host env vars into the container).

The Docker image pull remains the only release-time dependency on LocalStack itself.

Testing

Verified locally with lstk built from latest main: the exact pinned-style config plus lstk --config … start --timeout 2m / logs / stop all pass, with DEBUG output visible in the logs (env forwarding works). The test.yml path runs on this PR; the release.yml path is first exercised on the next release.

Review

Workflow-only change. Worth a skim of the release.yml diff since that path only runs during an actual release. Notes for reviewers: port is required in an lstk [[containers]] block (omitting it fails validation), and a tag the license server can't parse degrades to in-container license validation instead of failing the start.

Closes COSY-856

🤖 Generated with Claude Code

[aidehn]

out of curiosity is it possible at all to change the chosen image without using the config ?

[aidehn]

LGTM! Tests are passing so looks good! Thanks for picking this up - it means once we move away from the localstack CLI in our release there's less for us to do!

[aidehn]

hopefully at some point lstk releases a github action? 👀