gerrit, internal/task: add Gerrit-related release tasks

I refactored out the Gerrit-related code from MailDLCL, and added
support for waiting for submit and creating tags.

No test for creating tags but that logic has virtually nothing to it so
I think I'm okay with it?

For golang/go#51797.

Change-Id: Ia8c24536bbee27e0b7bef04769ac5a81dc3021ab
Reviewed-on: https://go-review.googlesource.com/c/build/+/408674
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Alex Rakoczy <alex@golang.org>
Run-TryBot: Heschi Kreinick <heschi@google.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>

gerrit/gerrit.go

@@ -66,7 +66,7 @@ type HTTPError struct {
 }
 
 func (e *HTTPError) Error() string {
-	return fmt.Sprintf("HTTP status %s; %s", e.Res.Status, e.Body)
+	return fmt.Sprintf("HTTP status %s on request to %s; %s", e.Res.Status, e.Res.Request.URL, e.Body)
 }
 
 // doArg is an optional argument for the Client.do method.
@@ -760,6 +760,13 @@ func (c *Client) ChangeFileContentInChangeEdit(ctx context.Context, changeID str
 	return err
 }
 
+// DeleteFileInChangeEdit deletes a file from a change edit.
+//
+// See https://gerrit-review.googlesource.com/Documentation/rest-api-changes.html#delete-edit-file.
+func (c *Client) DeleteFileInChangeEdit(ctx context.Context, changeID string, path string) error {
+	return c.do(ctx, nil, "DELETE", "/changes/"+changeID+"/edit/"+url.QueryEscape(path), wantResStatus(http.StatusNoContent))
+}
+
 // PublishChangeEdit promotes the change edit to a regular patch set.
 //
 // See https://gerrit-review.googlesource.com/Documentation/rest-api-changes.html#publish-edit.
@@ -876,6 +883,22 @@ func (c *Client) GetProjectTags(ctx context.Context, name string) (map[string]Ta
 	return m, nil
 }
 
+// TagInput contains information for creating a tag.
+// See https://gerrit-review.googlesource.com/Documentation/rest-api-projects.html#tag-input
+type TagInput struct {
+	// Ref is optional, and when present must be equal to the URL parameter. Removed.
+	Revision string `json:"revision,omitempty"`
+	Message  string `json:"message,omitempty"`
+}
+
+// CreateTag creates a tag on project.
+// See https://gerrit-review.googlesource.com/Documentation/rest-api-projects.html#create-tag.
+func (c *Client) CreateTag(ctx context.Context, project, tag string, input TagInput) (TagInfo, error) {
+	var res TagInfo
+	err := c.do(ctx, &res, "PUT", fmt.Sprintf("/projects/%s/tags/%s", project, url.PathEscape(tag)), reqBodyJSON{&input}, wantResStatus(http.StatusCreated))
+	return res, err
+}
+
 // GetAccountInfo gets the specified account's information from Gerrit.
 // For the API call, see https://gerrit-review.googlesource.com/Documentation/rest-api-accounts.html#get-account
 // The accountID is https://gerrit-review.googlesource.com/Documentation/rest-api-accounts.html#account-id

internal/task/dlcl.go

@@ -74,26 +74,16 @@ func MailDLCL(ctx *workflow.TaskContext, versions []string, e ExternalConfig) (c
 		return "(dry-run)", nil
 	}
 	cl := gerrit.NewClient(e.GerritAPI.URL, e.GerritAPI.Auth)
-	c, err := cl.CreateChange(ctx, gerrit.ChangeInput{
+	changeInput := gerrit.ChangeInput{
 		Project: "dl",
 		Subject: "dl: add " + strings.Join(versions, " and "),
 		Branch:  "master",
-	})
+	}
+	changeID, err := (&realGerritClient{client: cl}).CreateAutoSubmitChange(ctx, changeInput, files)
 	if err != nil {
 		return "", err
 	}
-	changeID := fmt.Sprintf("%s~%d", c.Project, c.ChangeNumber)
-	for path, content := range files {
-		err := cl.ChangeFileContentInChangeEdit(ctx, changeID, path, content)
-		if err != nil {
-			return "", err
-		}
-	}
-	err = cl.PublishChangeEdit(ctx, changeID)
-	if err != nil {
-		return "", err
-	}
-	return fmt.Sprintf("https://go.dev/cl/%d", c.ChangeNumber), nil
+	return changeLink(changeID), nil
 }
 
 func verifyGoVersions(versions ...string) error {

internal/task/gerrit.go

@@ -0,0 +1,100 @@
+package task
+
+import (
+	"context"
+	"fmt"
+	"strings"
+	"time"
+
+	"golang.org/x/build/gerrit"
+)
+
+type GerritClient interface {
+	// CreateAutoSubmitChange creates a change with the given metadata and contents, sets
+	// Run-TryBots and Auto-Submit, and returns its change ID.
+	// If the content of a file is empty, that file will be deleted from the repository.
+	CreateAutoSubmitChange(ctx context.Context, input gerrit.ChangeInput, contents map[string]string) (string, error)
+	// AwaitSubmit waits for the specified change to be auto-submitted or fail
+	// trybots. If the CL is submitted, returns the submitted commit hash.
+	AwaitSubmit(ctx context.Context, changeID string) (string, error)
+	// Tag creates a tag on project at the specified commit.
+	Tag(ctx context.Context, project, tag, commit string) error
+}
+
+type realGerritClient struct {
+	client *gerrit.Client
+}
+
+func (c *realGerritClient) CreateAutoSubmitChange(ctx context.Context, input gerrit.ChangeInput, files map[string]string) (string, error) {
+	change, err := c.client.CreateChange(ctx, input)
+	if err != nil {
+		return "", err
+	}
+	changeID := fmt.Sprintf("%s~%d", change.Project, change.ChangeNumber)
+	for path, content := range files {
+		if content == "" {
+			if err := c.client.DeleteFileInChangeEdit(ctx, changeID, path); err != nil {
+				return "", err
+			}
+		} else {
+			if err := c.client.ChangeFileContentInChangeEdit(ctx, changeID, path, content); err != nil {
+				return "", err
+			}
+		}
+	}
+
+	if err := c.client.PublishChangeEdit(ctx, changeID); err != nil {
+		return "", err
+	}
+	if err := c.client.SetReview(ctx, changeID, "current", gerrit.ReviewInput{
+		Labels: map[string]int{
+			"Run-TryBot":  1,
+			"Auto-Submit": 1,
+		},
+	}); err != nil {
+		return "", err
+	}
+	return changeID, nil
+}
+
+func (c *realGerritClient) AwaitSubmit(ctx context.Context, changeID string) (string, error) {
+	for {
+		detail, err := c.client.GetChangeDetail(ctx, changeID, gerrit.QueryChangesOpt{
+			Fields: []string{"CURRENT_REVISION", "DETAILED_LABELS"},
+		})
+		if err != nil {
+			return "", err
+		}
+		if detail.Status == "MERGED" {
+			return detail.CurrentRevision, nil
+		}
+		for _, approver := range detail.Labels["TryBot-Result"].All {
+			if approver.Value < 0 {
+				return "", fmt.Errorf("trybots failed on %v", changeLink(changeID))
+			}
+		}
+
+		select {
+		case <-ctx.Done():
+			return "", ctx.Err()
+		case <-time.After(10 * time.Second):
+		}
+	}
+}
+
+func (c *realGerritClient) Tag(ctx context.Context, project, tag, commit string) error {
+	_, err := c.client.CreateTag(ctx, project, tag, gerrit.TagInput{
+		Revision: commit,
+	})
+	return err
+}
+
+// changeLink returns a link to the review page for the CL with the specified
+// change ID. The change ID must be in the project~cl# form.
+func changeLink(changeID string) string {
+	parts := strings.SplitN(changeID, "~", 3)
+	if len(parts) != 2 {
+		return fmt.Sprintf("(unparseable change ID %q)", changeID)
+	}
+	return "https://go.dev/cl/" + parts[1]
+}

internal/task/version.go

@@ -0,0 +1,36 @@
+package task
+
+import (
+	"fmt"
+
+	"golang.org/x/build/gerrit"
+	"golang.org/x/build/internal/workflow"
+)
+
+// VersionTasks contains tasks related to versioning the release.
+type VersionTasks struct {
+	Gerrit  GerritClient
+	Project string
+}
+
+// CreateAutoSubmitVersionCL mails an auto-submit change to update VERSION on branch.
+func (t *VersionTasks) CreateAutoSubmitVersionCL(ctx *workflow.TaskContext, branch, version string) (string, error) {
+	return t.Gerrit.CreateAutoSubmitChange(ctx, gerrit.ChangeInput{
+		Project: t.Project,
+		Branch:  branch,
+		Subject: fmt.Sprintf("[%v] %v", branch, version),
+	}, map[string]string{
+		"VERSION": version,
+	})
+}
+
+// AwaitCL waits for the specified CL to be submitted.
+func (t *VersionTasks) AwaitCL(ctx *workflow.TaskContext, changeID string) (string, error) {
+	ctx.Printf("Awaiting review/submit of %v", changeLink(changeID))
+	return t.Gerrit.AwaitSubmit(ctx, changeID)
+}
+
+// TagRelease tags commit as version.
+func (t *VersionTasks) TagRelease(ctx *workflow.TaskContext, version, commit string) (string, error) {
+	return "", t.Gerrit.Tag(ctx, t.Project, version, commit)
+}

internal/task/version_test.go

@@ -0,0 +1,53 @@
+package task
+
+import (
+	"context"
+	"flag"
+	"strings"
+	"testing"
+
+	"golang.org/x/build/gerrit"
+	"golang.org/x/build/internal/workflow"
+)
+
+var flagRunVersionTest = flag.Bool("run-version-test", false, "run version test, which will submit CLs to go.googlesource.com/scratch. Must have a Gerrit cookie in gitcookies.")
+
+func TestVersion(t *testing.T) {
+	if !*flagRunVersionTest {
+		t.Skip("Not enabled by flags")
+	}
+	cl := gerrit.NewClient("https://go-review.googlesource.com", gerrit.GitCookiesAuth())
+	tasks := &VersionTasks{
+		Gerrit:  &realGerritClient{client: cl},
+		Project: "scratch",
+	}
+	ctx := &workflow.TaskContext{
+		Context: context.Background(),
+		Logger:  &testLogger{t},
+	}
+
+	changeID, err := tasks.CreateAutoSubmitVersionCL(ctx, "master", "version string")
+	if err != nil {
+		t.Fatal(err)
+	}
+	_, err = tasks.AwaitCL(ctx, changeID)
+	if strings.Contains(err.Error(), "trybots failed") {
+		t.Logf("Trybots failed, as they usually do: %v. Abandoning CL and ending test.", err)
+		if err := cl.AbandonChange(ctx, changeID, "test is done"); err != nil {
+			t.Fatal(err)
+		}
+		return
+	}
+
+	changeID, err = tasks.Gerrit.CreateAutoSubmitChange(ctx, gerrit.ChangeInput{
+		Project: "scratch",
+		Branch:  "master",
+		Subject: "Clean up VERSION",
+	}, map[string]string{"VERSION": ""})
+	if err != nil {
+		t.Fatalf("cleaning up VERSION: %v", err)
+	}
+	if _, err := tasks.AwaitCL(ctx, changeID); err != nil {
+		t.Fatalf("cleaning up VERSION: %v", err)
+	}
+}