Guardrails / docker

Dockerfile lint findings are clean

docker/lint-clean@v1

Every finding the Dockerfile linter reported sits below the severity the team gates on.

Id	docker/lint-clean
Version	v1
Category	docker
Default severity	warning
Interpreter	python3
Timeout	30 seconds
Violations tolerated	0
Collects	docker

Collectors

This guardrail gathers nothing itself. It depends on the collectors below, which the CLI runs once per build before any check, and reads what they found out of GUARDRAIL_FACTS. A collector that collects nothing skips this guardrail rather than failing it.

Collector	Gathers	Inputs it is given
docker	Every Dockerfile in the tree, parsed without a tool: the stages it builds, the image each one starts from and how that image is pinned, the user the image ends as, the ports it exposes, the paths it copies in and the names of the build arguments and environment variables it declares, enriched with the findings of a hadolint report when the build already left one behind.	none

The inputs above are this guardrail's own, passed straight through. Configuring one in buildnote.json changes what is collected, and two guardrails configured the same way share the one collection.

Configuration

{
  "guardrails": {
      "failOn": "error",
      "comment": true,
      "checks": [
          {
              "use": "docker/lint-clean@v1",
              "severity": "warning",
              "with": {
                  "severity": "high",
                  "ignore": ""
              },
              "exemptions": []
          }
      ]
  }
}

Inputs

Input	Description	Default	Environment variable
severity	Lowest severity that is a violation, on the scale the collector normalises every report onto. A finding below it is logged rather than reported. One of critical, high, medium, low, info.	high	GUARDRAIL_INPUT_SEVERITY
ignore	Comma separated rule ids that are never a violation, such as DL3008,DL3059.	``	GUARDRAIL_INPUT_IGNORE

How to fix

Fix the findings named in the violations, or silence a rule deliberately in .hadolint.yaml where it does not apply:

ignored:
  - DL3008

Run the linter in the build before this guardrail so there is a report to read:

hadolint --format sarif Dockerfile > hadolint.sarif

The report is read, never rerun: the guardrail judges the same findings the build acted on.

More in docker

• docker/base-pinned. Every image a Dockerfile builds from is pinned to a digest, so a rebuild of the same commit starts from the same bytes.
• docker/healthcheck. Every Dockerfile declares a HEALTHCHECK, so the orchestrator can tell a container that is running from one that is working.
• docker/no-build-secrets. No ARG or ENV a Dockerfile declares is named like a credential.
• docker/nonroot-user. Every Dockerfile ends on a USER that is not root, so the container runs its process unprivileged.

All 5 docker guardrails