Release Gates for Sensitive-Data APIs

A document-classification API depended on validation and preprocessing behavior that could change with a package update. A successful build did not tell me whether the endpoint still accepted the right input or returned the expected response.

Install the reviewed dependency versions

I used Poetry to pin the direct dependencies and keep the resolved dependency tree in a lockfile. Local development, CI, and the container needed to install from that same lockfile. Resolving packages again during deployment could produce a different environment from the one tested.

The excerpt shows the project configuration. The lockfile holds the resolved transitive versions; the container install must use it for those versions to carry through to the release.

Test the request, then start the built image

The release sequence ran validation tests, built the container, started that image, and sent generated payloads through the API. The test cases covered missing fields, malformed text, size limits, unexpected metadata, and the response shape.

locked install
→ validation tests
→ container build
→ startup check
→ synthetic request
→ staging gate

These fixtures exercised the contract without copying private document records into CI. An invalid payload needed the expected rejection, and an accepted payload needed the expected response fields. Checking only for HTTP 200 would miss either kind of regression.

Starting the image checked something the unit tests could not: whether the packaged application could boot with its entrypoint and runtime dependencies. The image sent to staging had to be the one that passed this check.

Keep deployment checks separate

The release gate covered installation, input handling, startup, and the tested response contract. Staging still needed checks for authentication, document access, retention, log contents, and deployment secrets.