log-linter

log-linter checks Go code for logging policy violations.

It runs as a golangci-lint module plugin custom linter named loglinter.

Current checks:

• disallowed log/slog imports unless allowlisted
• disallowed stdlib log.* calls unless allowlisted
• printf-style formatting directives in *zap.Logger message strings
• fmt.Sprintf(...) used as a zap message
• ad hoc zap root logger constructors not wrapped with .With(logging.Component(...)) in the same expression

Usage

Build a custom golangci-lint binary

A repo-root .custom-gcl.yml is included for the custom binary build.

From the repo root:

make golangci-lint-custom

That builds the binary through the Docker-based flow and outputs it to _out/custom-gcl.

Run it directly:

_out/custom-gcl run --config .golangci.yml

Enable the plugin in .golangci.yml

Add a custom linter entry like this:

version: "2"

linters:
  enable:
    - loglinter
  settings:
    custom:
      loglinter:
        type: module
        description: checks logging conventions
        settings:
          exclude:
            - "**/*_test.go"
            - "_out/**"
            - "vendor/**"
          rules:
            slog_imports:
              allow:
                - "internal/app/machined/pkg/runtime/v1alpha1/platform/vmware/vmware_supported.go"

The repository root is the directory containing the golangci-lint config file.

Config

All rules are enabled by default. An empty settings block applies every rule to every analyzed Go file under the repository root.

Use config mainly to carve out exceptions.

• allow is the recommended way to exempt files from a specific rule.
• exclude is a broader file skip for a rule or for the whole run.
• include is still supported when you intentionally want to narrow a rule, but the default is repo-wide enforcement.
• enabled: false explicitly disables a rule.
• globs are repo-relative, slash-separated, and support **.

Inline exceptions

A single issue can be ignored with a same-line or immediately preceding comment:

// loglint:ignore stdlib_log_calls compatibility adapter
log.Printf("allowed here")

Multiple rules can be listed as a comma-separated token:

// loglint:ignore stdlib_log_calls,zap_root_component reason

Use all to suppress every rule for the next line or same line.

Notes

• Once loglinter is enabled in .golangci.yml, use the custom binary (./custom-gcl) or make golangci-lint-custom; a stock golangci-lint binary will not have the plugin compiled in.
• The root-component check is intentionally conservative: it only accepts .With(logging.Component(...)) when that wrapper appears in the same expression as the configured constructor call.
• Constructor names and component helper calls are configurable.