GitLab cache and artifacts: define the build handoff

Acceleration data and required release output differ

A cache reuses files to reduce repeated work, such as downloading dependencies. An artifact retains a job's output for later jobs or review. A deployment that requires a specific compiled build should receive that output through an explicit artifact contract rather than hoping a cache entry exists.

Caches can be absent or replaced according to configuration and runner storage. Jobs should be able to recreate cacheable inputs from their declared source. Required release outputs need producer identity, dependency ordering and retention that match the delivery workflow.

Setup: map files to their purpose

List cached paths, artifact paths, producing jobs and consuming jobs. Distinguish dependency directories from final binaries, archives or frontend assets. Record the package lockfile and other inputs that determine whether a reused dependency set is compatible.

Inspect cache keys, fallback behavior, runner cache storage, protected-branch policy and artifact expiry. Different runners or protected contexts may not see the same cache. A workflow that works only after another branch warms a cache has an undeclared input that needs correction.

Inspect a failed handoff

1. Check whether the build job actually produced the expected files and uploaded them as the intended artifact. Preserve the producing pipeline and job identities.
2. Review the deployment job's dependencies or needs configuration and its artifact retrieval settings. A successful predecessor alone does not prove that its output was downloaded into the expected path.
3. Inspect cache restoration logs separately. Verify key construction and lockfile inputs, and confirm that a cache miss leads to a supported install or rebuild rather than deployment of an old directory.
4. Check artifact expiry and pipeline identity when promoting an older release. A similarly named artifact from another pipeline is not automatically a substitute for the approved build.

Illustrative incident: deployment works only on a warm runner

In this illustrative scenario, a deployment job expects compiled files stored only in a cache. On a reused runner the directory happens to exist, while a fresh runner fails or deploys an incomplete release. The workflow's source and job order look correct, but the required output was never declared as an artifact.

The team publishes the build result as a versioned artifact handoff and tests deployment on a clean runner. It retains a dependency cache only for acceleration. The example explains reproducibility and is not a claim about an actual customer deployment.

Diagnostic table

Correction and verification

Make required artifacts explicit and connect consumers to the correct producer. Use cache keys that reflect relevant dependency inputs and avoid broad writable sharing across incompatible trust contexts. Validate paths so restored cache data cannot accidentally replace the intended final build.

Exercise cold-cache, warm-cache and expired-artifact scenarios in a test project. Compare deployed output identity with the tested build. Confirm that cache misses affect duration rather than correctness, and that missing required artifacts stop deployment with a useful explanation.

SOP and monitoring

Document cache ownership, keys, runner-storage assumptions, artifact producers and retention. Review the contract when adding parallel jobs or changing branch protection. The SOP should let an operator identify the exact pipeline output needed for a release and recreate optional acceleration data without confusing either one with persistent application data or a backup.

See Clouvenix devops automation for implementation and operational handover.

Technical reference

Official reference 1; Official reference 2. Documentation checked 20 October 2026; confirm behavior for your deployed edition and version.