Merge pull request #30 from ThomasK33/main

Added wrapper for golangci-lint's module plugin system wrapper

go.mod

@@ -3,6 +3,7 @@ module sigs.k8s.io/logtools
 go 1.22
 
 require (
+	github.com/golangci/plugin-module-register v0.1.1
 	golang.org/x/exp v0.0.0-20240506185415-9bf2ced13842
 	golang.org/x/tools v0.21.0
 )

go.sum

@@ -1,3 +1,5 @@
+github.com/golangci/plugin-module-register v0.1.1 h1:TCmesur25LnyJkpsVrupv1Cdzo+2f7zX0H6Jkw1Ol6c=
+github.com/golangci/plugin-module-register v0.1.1/go.mod h1:TTpqoB6KkwOJMV8u7+NyXMrkwwESJLOkfl9TxR1DGFc=
 golang.org/x/exp v0.0.0-20240506185415-9bf2ced13842 h1:vr/HnozRka3pE4EsMEg1lgkXJkTFJCVUX+S/ZT6wYzM=
 golang.org/x/exp v0.0.0-20240506185415-9bf2ced13842/go.mod h1:XtvwrStGgqGPLc4cjQfWqZHG1YFdYs6swckp8vpsjnc=
 golang.org/x/mod v0.17.0 h1:zY54UmvipHiNd+pm+m0x9KhZ9hl1/7QNMyxXbc6ICqA=

logcheck/README.md

@@ -84,6 +84,7 @@ Format strings are not allowed where plain strings are expected.
 ### structured logging calls
 
 Key/value parameters for logging calls are checked:
+
 - For each key there must be a value.
 - Keys must be constant strings.
 
@@ -113,3 +114,62 @@ This check flags check whether name arguments are valid keys according to the
 
 This checks detects the usage of deprecated `klog` helper functions such as `KObjs` and suggests
 a suitable alternative to replace them with.
+
+# Golangci-lint
+
+Logcheck needs to be built as a plugin to golangci-lint to be executed as a
+private linter. There are two plugin systems in golangci-lint, and the following
+instructions apply to the [Module Plugin System](https://golangci-lint.run/plugins/module-plugins/)
+(introduced since v1.57.0), which is a supported approach to run Logcheck in golangci-lint.
+
+One will have to build a custom golangci-lint binary by doing:
+
+(1) Create a `.custom-gcl.yml` file at the root of the repository if you have not
+done so, add the following content:
+
+```yaml
+version: v1.59.1
+plugins:
+    - module: "sigs.k8s.io/logtools"
+      import: "sigs.k8s.io/logtools/logcheck/gclplugin"
+      version: latest
+```
+
+(2) Add logcheck to the linter configuration file `.golangci.yaml`:
+
+```yaml
+# This config disables all other linters and only runs logcheck
+# Configure the linters as all other linters. This is mostly
+# for brevity.
+linters:
+  disable-all: true
+  enable:
+    - logcheck
+
+linters-settings:
+  custom:
+    logcheck:
+      type: "module"
+      description: structured logging checker
+      original-url: sigs.k8s.io/logtools/logcheck
+      settings:
+        check:
+          contextual: true
+        config: |
+          structured .*
+          contextual .*
+
+```
+
+(3) Build a custom golangci-lint binary with logcheck included:
+
+```sh
+golangci-lint custom
+```
+
+(4) Run the custom binary instead of golangci-lint:
+
+```sh
+# Arguments are the same as `golangci-lint`.
+./custom-gcl run ./...
+```

logcheck/gclplugin/plugin.go

@@ -0,0 +1,88 @@
+/*
+Copyright 2024 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+// Package gclplugin implements the golangci-lint's module plugin interface for logcheck to be used
+// as a private linter in golangci-lint. See more details at
+// https://golangci-lint.run/plugins/module-plugins/.
+package gclplugin
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+
+	"github.com/golangci/plugin-module-register/register"
+	"golang.org/x/tools/go/analysis"
+	"sigs.k8s.io/logtools/logcheck/pkg"
+)
+
+func init() {
+	register.Plugin("logcheck", New)
+}
+
+type settings struct {
+	Check  map[string]bool `json:"check"`
+	Config string          `json:"config"`
+}
+
+// New Module Plugin System, see https://golangci-lint.run/plugins/module-plugins/.
+func New(pluginSettings interface{}) (register.LinterPlugin, error) {
+	// We could manually parse the settings. This would involve several
+	// type assertions. Encoding as JSON and then decoding into our
+	// settings struct is easier.
+	//
+	// The downside is that format errors are less user-friendly.
+	var buffer bytes.Buffer
+	if err := json.NewEncoder(&buffer).Encode(pluginSettings); err != nil {
+		return nil, fmt.Errorf("encoding settings as internal JSON buffer: %v", err)
+	}
+	var s settings
+	decoder := json.NewDecoder(&buffer)
+	decoder.DisallowUnknownFields()
+	if err := decoder.Decode(&s); err != nil {
+		return nil, fmt.Errorf("decoding settings from internal JSON buffer: %v", err)
+	}
+
+	return &LogcheckPlugin{settings: s}, nil
+}
+
+var _ register.LinterPlugin = (*LogcheckPlugin)(nil)
+
+type LogcheckPlugin struct {
+	settings settings
+}
+
+// BuildAnalyzers implements register.LinterPlugin.
+func (l *LogcheckPlugin) BuildAnalyzers() ([]*analysis.Analyzer, error) {
+	// Now create an analyzer and configure it.
+	analyzer, config := pkg.Analyser()
+
+	for check, enabled := range l.settings.Check {
+		if err := config.SetEnabled(check, enabled); err != nil {
+			// No need to wrap, the error is informative.
+			return nil, err
+		}
+	}
+
+	if err := config.ParseConfig(l.settings.Config); err != nil {
+		return nil, fmt.Errorf("parsing config: %v", err)
+	}
+
+	return []*analysis.Analyzer{analyzer}, nil
+}
+
+// GetLoadMode implements register.LinterPlugin.
+func (l *LogcheckPlugin) GetLoadMode() string { return register.LoadModeSyntax }