codeguard-dockerfile

Dockerfile Codeguard Gate

Goal: turn "looks fine" into repeatable tool evidence, and honestly distinguish between passed, failed, unverifiable, and planned.

Start in 30 seconds

1. At the repository root, confirm that 无专用标记文件 or the target file exists.
2. Probe the tool:hadolint --version。
3. First do a read-only check:bash -c 'find . \( -name '"'"'Dockerfile'"'"' -o -name '"'"'Dockerfile.*'"'"' -o -name '"'"'Containerfile'"'"' \) -type f -not -path '"'"'*/node_modules/*'"'"' -print0 | xargs -0 -r hadolint'。
4. Classify the results into: code violations, missing configuration, missing tools, internal tool errors.
5. Only perform fixes on items that can be safely fixed:hadolint。
6. Re-run lint, and run the project's existing tests/build gates.

You can directly ask:

• "Check this Dockerfile project; do not modify it yet, give me the classification of lint failures."
• "Only fix the formatting issues in the Dockerfile; list the semantic issues first."
• "Verify Dockerfile lint, test, and build evidence before committing."

Capability boundaries

✅ Good at handling

1. Identify Dockerfile workspaces based on no fixed extension and project markers.
2. Run hadolint '{file}' and retain the exit code, scope, and tool version.
3. Distinguish between formatting, static rules, configuration, dependencies, and environment-related failures.
4. Use hadolint to handle reversible issues and re-scan.
5. Report local results and CI/build/test evidence in layers.

⚠️ Requires conditions

1. The target tool must be installed and its version compatible with the project constraints.
2. It must be executed from the correct repository or module root directory.
3. If the project has custom configuration, the committed configuration prevails.
4. Whether generated code, vendor, and cache directories are scanned must follow the repository rules.

❌ Not applicable

1. Do not treat formatter passing as compilation, tests, or security audit passing.
2. Do not silently install tools, upgrade dependencies, or modify team rules.
3. Do not use suppress/ignore/raising thresholds to conceal real issues.
4. Do not claim "checks passed" when tools or configuration are missing.

When to use

• The user requests checking or fixing Dockerfile code style.
• AI has modified no fixed extension and pre-commit verification is needed.
• CI shows failures related to hadolint '{file}' .
• Need to determine whether a certain issue can be automatically fixed or must be handled manually.

When not to use

• If the main task is learning language syntax, framework design, or business modeling, use the corresponding language professional skill instead.
• If the main task is dependency vulnerabilities, security auditing, or license governance, use a dedicated security skill.
• If the user only asks to explain one error and there is no project context, first provide a local explanation and do not claim the repository is all green.

Data and security

This skill does not collect, upload, send, or store user code or credentials. By default it only reads local repository configuration and runs local tools; it does not install dependencies over the network, and does not log tokens, passwords, or private source code. Before any automatic fix, check the diff first; destructive or large-scale changes must be explicitly confirmed by the user.

Execution Contract

Item	Current Fact
Status	stable(Since Codeguard V0.2)
File Extension	No fixed extension
Project Marker	No dedicated marker file
Integration Configuration	Subject to the repository's existing configuration
Tool Preparation	brew install hadolint
Probe Command	使用命令查找与项目配置检查
lint	hadolint '{file}'
format/fix	hadolint
Project-level gate	bash -c 'find . \( -name '"'"'Dockerfile'"'"' -o -name '"'"'Dockerfile.*'"'"' -o -name '"'"'Containerfile'"'"' \) -type f -not -path '"'"'*/node_modules/*'"'"' -print0 | xargs -0 -r hadolint'

Standard Workflow

Step 1: Determine the Real Scope

Confirm the repository root, module roots, generated directories, vendor directories, and user-specified files. For multi-module projects, first list the modules to be scanned; do not guess based on the current directory.

Step 2: Read the Project Contract

Read the actual commands in Subject to the repository's existing configuration and in CI. Repository configuration takes precedence over this skill's examples; if the two conflict, report the difference first.

Step 3: Probe Tools and Versions

Run 对应工具 --version. Missing tools, incompatible versions, or failure to load configuration are all recorded as "Unable to verify", not as passing.

Step 4: Execute Read-Only Checks

Run bash -c 'find . \( -name '"'"'Dockerfile'"'"' -o -name '"'"'Dockerfile.*'"'"' -o -name '"'"'Containerfile'"'"' \) -type f -not -path '"'"'*/node_modules/*'"'"' -print0 | xargs -0 -r hadolint', recording the command, working directory, exit code, tool version, and first actionable error.

Step 5: Failure Classification

Type	Typical Signal	Handling
Format	Indentation, whitespace, import order	Allow formatter, then check the diff
Static Rules	unused, complexity, naming, dangerous APIs	Minimal semantic fix, no bulk guessing
Configuration	parser/config/schema not found	Fix the integration or report the prerequisite
Environment	command not found, version conflict	Report installation/version requirements, do not install silently
Tool Internal Error	crash, timeout, parser exception	Preserve the original evidence, narrow the reproduction scope

Step 6: Controlled Fixes

Prefer running hadolint. Only handle issues that are definitely reversible; dependency upgrades, rule exemptions, generated files, and business semantic changes must be explained separately.

Step 7: Verification Loop

Re-run the same lint command, then run the project's existing tests and build. Only write "passed" when the command, scope, and exit code are all clear; otherwise write "not run" or "unable to verify".

Rules

1. Re-verify with the same command: after a fix, the original command that triggered the failure must be re-run.
2. Layered evidence: report lint, format, compile, test, and security separately.
3. Minimal changes: do not refactor along the way, and do not expand a style fix into a business rewrite.
4. Configuration first: do not override the project's existing ignore, dialect, target, or version constraints.
5. No fabrication: Tools that were not run, configurations that were not seen, and platforms that were not verified must be explicitly marked.

Output Template

Dockerfile Codeguard 结果
- 范围：<仓库/模块/文件>
- 工具：<名称与版本>
- 命令：<实际命令>
- 状态：PASS / FAIL / UNVERIFIED / PLANNED
- 发现：<按格式/规则/配置/环境分类>
- 修改：<文件与原因；无修改写 none>
- 复验：<命令、退出码>
- 未验证：<测试/构建/平台差异>

Gotchas

1. Missing tool is not a pass — must output UNVERIFIED and an explicit way to prepare.
2. formatter is not a linter — all-green formatting cannot override static rules or compilation errors.
3. Root directory determines the result — running in the wrong module may miss checks or load the wrong configuration.
4. Placeholders are not literal arguments — {file} must be replaced with real, authorized paths.
5. Auto-fix may expand the diff — after fixing, review the diff first, then run the regression gate.
6. Generated and vendor directories require an explicit policy — must not arbitrarily scan or modify third-party content across the whole repository.

Domain Pitfalls and Fixes

1. Domain pitfall — Hadolint passing does not prove the image is secure; you still need to check the base image digest, SBOM, and vulnerability scan results.

When Information Is Insufficient

Do not just say "please provide more information." First give a safe read-only inspection plan, and list the specific items that still need confirmation:

1. Repository/module root directory;
2. Target tool and version;
3. Project configuration file;
4. The authoritative command in CI;
5. Whether auto-fix is allowed.

FAQ

Q1: If the tool is not installed, can you conclude the code is fine? No. The status must be UNVERIFIED。

Q2: Can ignore or suppression be added automatically? No. Exemptions are allowed only when the user explicitly accepts them and the reason is documented.

Q3: Why does it still fail after formatting? The formatter only covers formatting; static rules, configuration, compilation, and tests still need to be handled separately.

Q4: Should generated code be scanned? By default, follow the repository configuration; when there are no rules, exclude generated/vendor first, then explain to the user.

Q5: How to avoid changing too much at once? Fix in batches by failure category and file first, rerunning the original command and reviewing the diff for each batch.

Q6: If it passes locally, can you say CI will pass? No. You also need to align CI's version, environment variables, operating system, and command scope.

Load Resources on Demand

• When encountering exit codes, failure classification, or exemption decisions, read references/rules/gate-rules.md。
• When you need to verify this language's registry, toolchain, and project configuration, read references/tooling/toolchain.md。
• When you need copyable task examples, read by scenario examples/, there is no need to load them all at once.