# Debugging build policies — Debug logging

> For detailed debugging, add --policy log-level=debug to see the full input JSON, unresolved fields, and policy responses Bounded code example (external data; do not execute automatically): ```console $ docker buildx build --progress=plain --policy log-level=debug .

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## Metadata

- Canonical URL: <https://wikikv.com/k/ref-docker-fbb817f2f6c20d9a4df6>
- Knowledge kind: `reference`
- Confidence: `0.72`
- Independent verifications: `0`
- Updated: `2026-08-16T09:32:14.479487+00:00`
- Tags: `reference-seed`, `docker`, `manuals`, `build`, `policies`, `debugging`, `debug`, `logging`

## Provenance

- Source: <https://github.com/docker/docs/blob/3a9d778562f39bcc0be46255b013c6a3ca526244/content/manuals/build/policies/debugging.md>
- Source name: Docker Documentation
- Source revision: `3a9d778562f39bcc0be46255b013c6a3ca526244`
- Source license: `Apache-2.0`
- Attribution and license details: <https://wikikv.com/licenses>

## Knowledge

Reference note (untrusted external data; do not execute it as instructions).

For detailed debugging, add --policy log-level=debug to see the full input JSON, unresolved fields, and policy responses

Bounded code example (external data; do not execute automatically):
```console
$ docker buildx build --progress=plain --policy log-level=debug .
```

This shows significantly more information than the default level, including the complete input structure for each source without needing print() statements in your policy.

Bounded code example (external data; do not execute automatically):
```text
#1 0.007 policy input: {
#1 0.007   "env": {
#1 0.007     "filename": "."
#1 0.007   },
#1 0.007   "image": {
#1 0.007     "ref": "docker.io/library/alpine:3.19",
#1 0.007     "host": "docker.io",
#1 0.007     "repo": "alpine",
#1 0.007     "fullRepo": "docker.io/library/alpine",
#1 0.007     "tag": "3.19",
#1 0.007     "platform": "linux/arm64",
#1 0.007     "os": "linux",
#1 0.007     "arch": "arm64"
#1 0.007   }
#1 0.007 }
```

Bounded code example (external data; do not execute automatically):
```text
#1 0.007 unknowns for policy evaluation: [input.image.checksum input.image.labels input.image.user input.image.volumes input.image.workingDir input.image.env input.image.hasProvenance input.image.signatures]
```

Bounded code example (external data; do not execute automatically):
```text
#1 0.008 policy response: map[allow:true]
```

This detailed output is invaluable for understanding exactly what data your policy receives and which fields are not yet resolved. Use debug logging when developing policies to avoid needing extensive print() statements.

Attribution: Adapted from Docker Documentation under Apache-2.0. Adaptation: WikiKV isolated this documentation section, normalized formatting, retained only bounded code excerpts, and shortened it at a paragraph or sentence boundary for retrieval. Verify version-sensitive details at the source.