[autodetect] Add go autodetection (#2381)

## Summary

TSIA. 

## How was it tested?

unit tests

Author: mikeland73

pkg/autodetect/autodetect.go

@@ -43,6 +43,7 @@ func detectors(path string) []detector.Detector {
 	return []detector.Detector{
 		&detector.PythonDetector{Root: path},
 		&detector.PoetryDetector{Root: path},
+		&detector.GoDetector{Root: path},
 	}
 }
 

pkg/autodetect/detector/go.go

@@ -0,0 +1,53 @@
+package detector
+
+import (
+	"context"
+	"os"
+	"path/filepath"
+	"regexp"
+)
+
+type GoDetector struct {
+	Root string
+}
+
+var _ Detector = &GoDetector{}
+
+func (d *GoDetector) Relevance(path string) (float64, error) {
+	goModPath := filepath.Join(d.Root, "go.mod")
+	_, err := os.Stat(goModPath)
+	if err == nil {
+		return 1.0, nil
+	}
+	if os.IsNotExist(err) {
+		return 0, nil
+	}
+	return 0, err
+}
+
+func (d *GoDetector) Packages(ctx context.Context) ([]string, error) {
+	goModPath := filepath.Join(d.Root, "go.mod")
+	goModContent, err := os.ReadFile(goModPath)
+	if err != nil {
+		return nil, err
+	}
+
+	// Parse the Go version from go.mod
+	goVersion := parseGoVersion(string(goModContent))
+	if goVersion != "" {
+		return []string{"go@" + goVersion}, nil
+	}
+	return []string{"go@latest"}, nil
+}
+
+func parseGoVersion(goModContent string) string {
+	// Use a regular expression to find the Go version directive
+	re := regexp.MustCompile(`(?m)^go\s+(\d+\.\d+(\.\d+)?)`)
+	match := re.FindStringSubmatch(goModContent)
+
+	if len(match) >= 2 {
+		return match[1]
+	}
+
+	return ""
+}

pkg/autodetect/detector/go_test.go

@@ -0,0 +1,103 @@
+package detector
+
+import (
+	"context"
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestGoDetectorRelevance(t *testing.T) {
+	tempDir := t.TempDir()
+	detector := &GoDetector{Root: tempDir}
+
+	t.Run("No go.mod file", func(t *testing.T) {
+		relevance, err := detector.Relevance(tempDir)
+		assert.NoError(t, err)
+		assert.Equal(t, 0.0, relevance)
+	})
+
+	t.Run("With go.mod file", func(t *testing.T) {
+		err := os.WriteFile(filepath.Join(tempDir, "go.mod"), []byte("module example.com"), 0o644)
+		assert.NoError(t, err)
+
+		relevance, err := detector.Relevance(tempDir)
+		assert.NoError(t, err)
+		assert.Equal(t, 1.0, relevance)
+	})
+}
+
+func TestGoDetectorPackages(t *testing.T) {
+	tempDir := t.TempDir()
+	detector := &GoDetector{Root: tempDir}
+
+	t.Run("No go.mod file", func(t *testing.T) {
+		packages, err := detector.Packages(context.Background())
+		assert.Error(t, err)
+		assert.Nil(t, packages)
+	})
+
+	t.Run("With go.mod file and no version", func(t *testing.T) {
+		err := os.WriteFile(filepath.Join(tempDir, "go.mod"), []byte("module example.com"), 0o644)
+		assert.NoError(t, err)
+
+		packages, err := detector.Packages(context.Background())
+		assert.NoError(t, err)
+		assert.Equal(t, []string{"go@latest"}, packages)
+	})
+
+	t.Run("With go.mod file and specific version", func(t *testing.T) {
+		goModContent := `
+module example.com
+
+go 1.18
+`
+		err := os.WriteFile(filepath.Join(tempDir, "go.mod"), []byte(goModContent), 0o644)
+		assert.NoError(t, err)
+
+		packages, err := detector.Packages(context.Background())
+		assert.NoError(t, err)
+		assert.Equal(t, []string{"[email protected]"}, packages)
+	})
+}
+
+func TestParseGoVersion(t *testing.T) {
+	testCases := []struct {
+		name     string
+		content  string
+		expected string
+	}{
+		{
+			name:     "No version",
+			content:  "module example.com",
+			expected: "",
+		},
+		{
+			name: "With version",
+			content: `
+module example.com
+
+go 1.18
+`,
+			expected: "1.18",
+		},
+		{
+			name: "With patch version",
+			content: `
+module example.com
+
+go 1.18.3
+`,
+			expected: "1.18.3",
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			version := parseGoVersion(tc.content)
+			assert.Equal(t, tc.expected, version)
+		})
+	}
+}