Docker build context or Dockerfile path issue

What this failure means

Docker could not read the Dockerfile or a required file from the selected build context, so the image build stopped before executing the full build.

Symptoms

Faultline looks for one or more of these log fragments:

failed to solve with frontend dockerfile.v0
failed to read dockerfile
dockerfile: no such file or directory
failed to compute cache key
file not found in build context or excluded by .dockerignore
forbidden path outside the build context
unable to prepare context
not found: not found

Diagnosis

Docker could not read the Dockerfile or a required file from the selected build context, so the image build stopped before executing the full build.

This usually means the command ran from the wrong directory, used the wrong -f path, or excluded required files via .dockerignore.

Fix steps

1. Verify the exact docker build command and confirm the final argument points at the intended build context.
2. Check that the Dockerfile path exists relative to the working directory or the -f flag.
3. Inspect .dockerignore for patterns that exclude required files such as lockfiles or source directories.
4. Re-run the same command locally from a clean checkout to confirm the context contents.

Validation

• Re-run the local reproduction command after the fix.
• Confirm Docker can read the Dockerfile and required build inputs from the selected context.

Why it matters

If Docker cannot see the intended context or Dockerfile, the build fails before any meaningful image assembly happens.

Prevention

• Keep Docker build commands explicit in CI, including both -f and context path.
• Add a lightweight image build smoke test to pull requests that touch Docker-related files.
• Avoid broad .dockerignore globs that can silently exclude required inputs.
• Keep Dockerfiles close to their intended build context so path assumptions stay obvious during refactors.

Try it locally

docker build -f Dockerfile .
docker build -f Dockerfile .

How Faultline detects it

Use faultline explain docker-build-context to see the full playbook.

faultline analyze build.log
faultline explain docker-build-context

Generated from playbooks/bundled/log/build/docker-build-context.yaml. Do not edit directly.