Add check for github codeowners file

magefile.go

@@ -7,26 +7,36 @@
 package main
 
 import (
+	"bufio"
+	"io/fs"
+	"io/ioutil"
 	"os"
 	"path/filepath"
+	"strings"
 
 	"github.com/magefile/mage/mg"
 	"github.com/magefile/mage/sh"
 	"github.com/pkg/errors"
+	"gopkg.in/yaml.v2"
 )
 
 var (
 	// GoImportsLocalPrefix is a string prefix matching imports that should be
 	// grouped after third-party packages.
 	GoImportsLocalPrefix = "github.com/elastic"
+)
 
+const (
 	buildDir = "./build"
+
+	codeownersPath = ".github/CODEOWNERS"
 )
 
 func Check() error {
 	mg.Deps(build)
 	mg.Deps(format)
 	mg.Deps(modTidy)
+	mg.Deps(checkPackageOwners)
 	return nil
 }
 
@@ -109,3 +119,96 @@ func findFilesRecursive(match func(path string, info os.FileInfo) bool) ([]strin
 func modTidy() error {
 	return sh.RunV("go", "mod", "tidy")
 }
+
+func checkPackageOwners() error {
+	codeowners, err := readGithubOwners()
+	if err != nil {
+		return err
+	}
+
+	const packagesDir = "packages"
+	return filepath.WalkDir(packagesDir, func(path string, d fs.DirEntry, err error) error {
+		if d.IsDir() {
+			if path != packagesDir && filepath.Dir(path) != packagesDir {
+				return fs.SkipDir
+			}
+			return nil
+		}
+		if d.Name() != "manifest.yml" {
+			return nil
+		}
+
+		return codeowners.checkManifest(path)
+	})
+}
+
+type githubOwners map[string][]string
+
+func readGithubOwners() (githubOwners, error) {
+	f, err := os.Open(codeownersPath)
+	if err != nil {
+		return nil, errors.Wrapf(err, "failed to open %q", codeownersPath)
+	}
+	defer f.Close()
+
+	codeowners := make(githubOwners)
+
+	scanner := bufio.NewScanner(f)
+	lineNumber := 0
+	for scanner.Scan() {
+		lineNumber++
+		line := strings.TrimSpace(scanner.Text())
+		if len(line) == 0 || strings.HasPrefix(line, "#") {
+			continue
+		}
+		fields := strings.Fields(line)
+		if len(fields) < 2 {
+			return nil, errors.Errorf("invalid line %d in %q: %q", lineNumber, codeownersPath, line)
+		}
+		path, owners := fields[0], fields[1:]
+
+		// It is ok to overwrite because latter lines have precedence in these files.
+		codeowners[path] = owners
+	}
+
+	return codeowners, nil
+}
+
+func (codeowners githubOwners) checkManifest(path string) error {
+	pkgDir := filepath.Dir(path)
+	owners, found := codeowners["/"+pkgDir]
+	if !found {
+		return errors.Errorf("there is no owner for %q in %q", pkgDir, codeownersPath)
+	}
+
+	content, err := ioutil.ReadFile(path)
+	if err != nil {
+		return err
+	}
+
+	var manifest struct {
+		Owner struct {
+			Github string `yaml:"github"`
+		} `yaml:"owner"`
+	}
+	err = yaml.Unmarshal(content, &manifest)
+	if err != nil {
+		return err
+	}
+
+	if manifest.Owner.Github == "" {
+		return errors.Errorf("no owner specified in %q", path)
+	}
+
+	found = false
+	for _, owner := range owners {
+		if owner == "@"+manifest.Owner.Github {
+			found = true
+			break
+		}
+	}
+	if !found {
+		return errors.Errorf("owner %q defined in %q is not in %q", manifest.Owner.Github, path, codeownersPath)
+	}
+	return nil
+}