loggercheck

README

loggercheck

Description

A linter checks the odd number of key and value pairs for common logger libraries:

• kitlog
• klog
• logr
• log/slog
• zap

For klog and logr, it also reports pointer values whose element type implements fmt.Stringer (for example *metav1.Time, which embeds time.Time). When such a pointer is nil, klog and logr's funcr render it as <panic: runtime error: invalid memory address or nil pointer dereference>. Wrap the value with klog.SafePtr, check it for nil first, or call .String() when it cannot be nil. Values that are provably non-nil at the call site, such as &T{} or a pointer used after a != nil check or a nil guard that returns or exits, are not reported.

It's recommended to use loggercheck with golangci-lint.

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Install

go install github.com/timonwong/loggercheck/cmd/loggercheck

Usage

loggercheck: Checks key value pairs for common logger libraries (kitlog,klog,logr,slog,zap).

Usage: loggercheck [-flag] [package]


Flags:
  -V    print version and exit
  -all
        no effect (deprecated)
  -c int
        display offending line with this many lines of context (default -1)
  -cpuprofile string
        write CPU profile to this file
  -debug string
        debug flags, any subset of "fpstv"
  -disable value
        comma-separated list of disabled logger checker (kitlog,klog,logr,slog,zap) (default kitlog)
  -fix
        apply all suggested fixes
  -flags
        print analyzer flags in JSON
  -json
        emit JSON output
  -memprofile string
        write memory profile to this file
  -noprintflike
        require printf-like format specifier not present in args
  -requirestringkey
        require all logging keys to be inlined constant strings
  -rulefile string
        path to a file contains a list of rules
  -source
        no effect (deprecated)
  -tags string
        no effect (deprecated)
  -test
        indicates whether test files should be analyzed, too (default true)
  -trace string
        write trace log to this file
  -v    no effect (deprecated)

Example

package a

import (
	"context"
	"fmt"

	"github.com/go-logr/logr"
)

func Example() {
	log := logr.Discard()
	log = log.WithValues("key")
	log.Info("message", "key1", "value1", "key2", "value2", "key3")
	log.Error(fmt.Errorf("error"), "message", "key1", "value1", "key2")
	log.Error(fmt.Errorf("error"), "message", "key1", "value1", "key2", "value2")

	var log2 logr.Logger
	log2 = log
	log2.Info("message", "key1")

	log3 := logr.FromContextOrDiscard(context.TODO())
	log3.Error(fmt.Errorf("error"), "message", "key1")
}

a.go:12:23: odd number of arguments passed as key-value pairs for logging
a.go:13:22: odd number of arguments passed as key-value pairs for logging
a.go:14:44: odd number of arguments passed as key-value pairs for logging
a.go:19:23: odd number of arguments passed as key-value pairs for logging
a.go:22:45: odd number of arguments passed as key-value pairs for logging

Documentation

Index

• Constants
• func NewAnalyzer(opts ...Option) *analysis.Analyzer
• type Option
  • func WithDisable(disable []string) Option
  • func WithNoPrintfLike(noPrintfLike bool) Option
  • func WithRequireStringKey(requireStringKey bool) Option
  • func WithRules(customRules []string) Option

Constants

const Doc = `Checks key value pairs for common logger libraries (kitlog,klog,logr,slog,zap).`

Functions

func NewAnalyzer

func NewAnalyzer(opts ...Option) *analysis.Analyzer

Types

type Option

type Option func(*loggercheck)

func WithDisable

func WithDisable(disable []string) Option

func WithNoPrintfLike

func WithNoPrintfLike(noPrintfLike bool) Option

func WithRequireStringKey

func WithRequireStringKey(requireStringKey bool) Option

func WithRules

func WithRules(customRules []string) Option