feat(internal/librarian): tag-and-release logic (#1812)

Fixes: #1009

Author: codyoss

internal/config/state.go

@@ -67,6 +67,16 @@ func (s *LibrarianState) ImageRefAndTag() (ref string, tag string) {
 	return parseImage(s.Image)
 }
 
+// LibraryByID returns the library with the given ID, or nil if not found.
+func (s *LibrarianState) LibraryByID(id string) *LibraryState {
+	for _, lib := range s.Libraries {
+		if lib.ID == id {
+			return lib
+		}
+	}
+	return nil
+}
+
 // parseImage splits an image string into its reference and tag.
 // It correctly handles port numbers in the reference.
 // If no tag is found, the tag part is an empty string.

internal/config/state_test.go

@@ -17,6 +17,8 @@ package config
 import (
 	"strings"
 	"testing"
+
+	"github.com/google/go-cmp/cmp"
 )
 
 func TestLibrarianState_Validate(t *testing.T) {
@@ -198,7 +200,7 @@ func TestLibrary_Validate(t *testing.T) {
 				ID:            "a/b",
 				SourceRoots:   []string{"src/a"},
 				APIs:          []*API{{Path: "a/b/v1"}},
-				PreserveRegex: []string{".*\\.txt"},
+				PreserveRegex: []string{`. * \\.txt`},
 			},
 		},
 		{
@@ -218,7 +220,7 @@ func TestLibrary_Validate(t *testing.T) {
 				ID:          "a/b",
 				SourceRoots: []string{"src/a"},
 				APIs:        []*API{{Path: "a/b/v1"}},
-				RemoveRegex: []string{".*\\.log"},
+				RemoveRegex: []string{`. * \\.log`},
 			},
 		},
 		{
@@ -408,3 +410,39 @@ func TestIsValidImage(t *testing.T) {
 		})
 	}
 }
+
+func TestLibraryState_LibraryByID(t *testing.T) {
+	for _, test := range []struct {
+		name      string
+		libraries []*LibraryState
+		id        string
+		want      *LibraryState
+	}{
+		{
+			name: "found",
+			libraries: []*LibraryState{
+				{ID: "foo"},
+				{ID: "bar"},
+			},
+			id:   "foo",
+			want: &LibraryState{ID: "foo"},
+		},
+		{
+			name: "not found",
+			libraries: []*LibraryState{
+				{ID: "foo"},
+				{ID: "bar"},
+			},
+			id:   "baz",
+			want: nil,
+		},
+	} {
+		t.Run(test.name, func(t *testing.T) {
+			state := &LibrarianState{Libraries: test.libraries}
+			got := state.LibraryByID(test.id)
+			if diff := cmp.Diff(test.want, got); diff != "" {
+				t.Errorf("LibraryState.LibraryByID() mismatch (-want +got):\n%s", diff)
+			}
+		})
+	}
+}

internal/librarian/mocks_test.go

@@ -39,16 +39,19 @@ type mockGitHubClient struct {
 	replaceLabelsCalls      int
 	searchPullRequestsCalls int
 	getPullRequestCalls     int
+	createReleaseCalls      int
 	createPullRequestErr    error
 	addLabelsToIssuesErr    error
 	getLabelsErr            error
 	replaceLabelsErr        error
 	searchPullRequestsErr   error
 	getPullRequestErr       error
+	createReleaseErr        error
 	createdPR               *github.PullRequestMetadata
 	labels                  []string
 	pullRequests            []*github.PullRequest
 	pullRequest             *github.PullRequest
+	createdRelease          *github.RepositoryRelease
 }
 
 func (m *mockGitHubClient) GetRawContent(ctx context.Context, path, ref string) ([]byte, error) {
@@ -88,6 +91,11 @@ func (m *mockGitHubClient) GetPullRequest(ctx context.Context, number int) (*git
 	return m.pullRequest, m.getPullRequestErr
 }
 
+func (m *mockGitHubClient) CreateRelease(ctx context.Context, tagName, releaseName, body, commitish string) (*github.RepositoryRelease, error) {
+	m.createReleaseCalls++
+	return m.createdRelease, m.createReleaseErr
+}
+
 // mockContainerClient is a mock implementation of the ContainerClient interface for testing.
 type mockContainerClient struct {
 	ContainerClient

internal/librarian/release_please_lite.go

@@ -29,7 +29,7 @@ const defaultTagFormat = "{id}-{version}"
 // GetConventionalCommitsSinceLastRelease returns all conventional commits for the given library since the
 // version specified in the state file.
 func GetConventionalCommitsSinceLastRelease(repo gitrepo.Repository, library *config.LibraryState) ([]*conventionalcommits.ConventionalCommit, error) {
-	tag := formatTag(library)
+	tag := formatTag(library, "")
 	commits, err := repo.GetCommitsForPathsSinceTag(library.SourceRoots, tag)
 	if err != nil {
 		return nil, fmt.Errorf("failed to get commits for library %s: %w", library.ID, err)
@@ -74,12 +74,16 @@ func shouldExclude(files, excludePaths []string) bool {
 }
 
 // formatTag returns the git tag for a given library version.
-func formatTag(library *config.LibraryState) string {
+func formatTag(library *config.LibraryState, versionOverride string) string {
+	version := library.Version
+	if versionOverride != "" {
+		version = versionOverride
+	}
 	tagFormat := library.TagFormat
 	if tagFormat == "" {
 		tagFormat = defaultTagFormat
 	}
-	r := strings.NewReplacer("{id}", library.ID, "{version}", library.Version)
+	r := strings.NewReplacer("{id}", library.ID, "{version}", version)
 	return r.Replace(tagFormat)
 }
 

internal/librarian/release_please_lite_test.go

@@ -110,7 +110,7 @@ func TestFormatTag(t *testing.T) {
 		},
 	} {
 		t.Run(test.name, func(t *testing.T) {
-			got := formatTag(test.library)
+			got := formatTag(test.library, "")
 			if got != test.want {
 				t.Errorf("formatTag() = %q, want %q", got, test.want)
 			}

internal/librarian/tag_and_release.go

@@ -20,6 +20,7 @@ import (
 	"fmt"
 	"log/slog"
 	"regexp"
+	"slices"
 	"strconv"
 	"strings"
 	"time"
@@ -33,6 +34,8 @@ import (
 const (
 	pullRequestSegments  = 5
 	tagAndReleaseCmdName = "tag-and-release"
+	releasePendingLabel  = "release:pending"
+	releaseDoneLabel     = "release:done"
 )
 
 var (
@@ -135,22 +138,39 @@ func (r *tagAndReleaseRunner) determinePullRequestsToProcess(ctx context.Context
 
 	slog.Info("searching for pull requests to tag and release")
 	thirtyDaysAgo := time.Now().Add(-30 * 24 * time.Hour).Format(time.RFC3339)
-	query := fmt.Sprintf("label:release:pending merged:>=%s", thirtyDaysAgo)
+	query := fmt.Sprintf("label:%s merged:>=%s", releasePendingLabel, thirtyDaysAgo)
 	prs, err := r.ghClient.SearchPullRequests(ctx, query)
 	if err != nil {
 		return nil, fmt.Errorf("failed to search pull requests: %w", err)
 	}
 	return prs, nil
 }
 
-func (r *tagAndReleaseRunner) processPullRequest(_ context.Context, p *github.PullRequest) error {
+func (r *tagAndReleaseRunner) processPullRequest(ctx context.Context, p *github.PullRequest) error {
 	slog.Info("processing pull request", "pr", p.GetNumber())
-	// hack to make CI happy until we impl
-	// TODO(https://github.com/googleapis/librarian/issues/1009)
-	if p.GetNumber() != 0 {
-		return fmt.Errorf("skipping pull request %d", p.GetNumber())
+	releases := parsePullRequestBody(p.GetBody())
+	if len(releases) == 0 {
+		slog.Warn("no release details found in pull request body, skipping")
+		return nil
 	}
-	return nil
+	for _, release := range releases {
+		slog.Info("creating release", "library", release.Library, "version", release.Version)
+		commitish := p.GetMergeCommitSHA()
+
+		lib := r.state.LibraryByID(release.Library)
+		if lib == nil {
+			return fmt.Errorf("library %s not found", release.Library)
+		}
+
+		// Create the release.
+		tagName := formatTag(lib, release.Version)
+		releaseName := fmt.Sprintf("%s %s", release.Library, release.Version)
+		if _, err := r.ghClient.CreateRelease(ctx, tagName, releaseName, release.Body, commitish); err != nil {
+			return fmt.Errorf("failed to create release: %w", err)
+		}
+
+	}
+	return r.replacePendingLabel(ctx, p)
 }
 
 // libraryRelease holds the parsed information from a pull request body.
@@ -188,3 +208,19 @@ func parsePullRequestBody(body string) []libraryRelease {
 
 	return parsedBodies
 }
+
+// replacePendingLabel is a helper function that replaces the `release:pending` label with `release:done`.
+func (r *tagAndReleaseRunner) replacePendingLabel(ctx context.Context, p *github.PullRequest) error {
+	var currentLabels []string
+	for _, label := range p.Labels {
+		currentLabels = append(currentLabels, label.GetName())
+	}
+	currentLabels = slices.DeleteFunc(currentLabels, func(s string) bool {
+		return s == releasePendingLabel
+	})
+	currentLabels = append(currentLabels, releaseDoneLabel)
+	if err := r.ghClient.ReplaceLabels(ctx, p.GetNumber(), currentLabels); err != nil {
+		return fmt.Errorf("failed to replace labels: %w", err)
+	}
+	return nil
+}