[Prototyping] Listen to pull requests and comment (#97040)

* Listen to Pull Requests and comment

* Fix template

pkg/registry/apis/provisioning/repository/github.go

@@ -1,6 +1,7 @@
 package repository
 
 import (
+	"bytes"
 	"context"
 	"errors"
 	"fmt"
@@ -9,6 +10,7 @@ import (
 	"net/url"
 	"regexp"
 	"strings"
+	"text/template"
 
 	"github.com/google/go-github/v66/github"
 	apierrors "k8s.io/apimachinery/pkg/api/errors"
@@ -347,7 +349,16 @@ func (r *githubRepository) Webhook(ctx context.Context, logger *slog.Logger, res
 			}
 
 			responder.Object(200, &metav1.Status{
-				Message: "event processed",
+				Message: "push event processed",
+				Code:    http.StatusOK,
+			})
+		case *github.PullRequestEvent:
+			if err := r.onPullRequestEvent(ctx, logger, event); err != nil {
+				responder.Error(err)
+				return
+			}
+			responder.Object(200, &metav1.Status{
+				Message: "pull request event processed",
 				Code:    http.StatusOK,
 			})
 		case *github.PingEvent:
@@ -421,12 +432,99 @@ func (r *githubRepository) onPushEvent(ctx context.Context, logger *slog.Logger,
 	return nil
 }
 
+// onPullRequestEvent is called when a pull request event is received
+// If the pull request is opened, reponed or synchronize, we read the files changed.
+func (r *githubRepository) onPullRequestEvent(ctx context.Context, logger *slog.Logger, event *github.PullRequestEvent) error {
+	action := event.GetAction()
+	r.logger.InfoContext(ctx, "processing pull request event", "number", event.GetNumber(), "action", action)
+
+	if event.GetRepo() == nil {
+		return fmt.Errorf("missing repository in pull request event")
+	}
+
+	if event.GetRepo().GetFullName() != fmt.Sprintf("%s/%s", r.config.Spec.GitHub.Owner, r.config.Spec.GitHub.Repository) {
+		return fmt.Errorf("repository mismatch")
+	}
+
+	if action != "opened" && action != "reopened" && action != "synchronize" {
+		logger.InfoContext(ctx, "ignore pull request event", "action", event.GetAction())
+		return nil
+	}
+
+	// Get the files changed in the pull request
+	files, err := r.gh.ListPullRequestFiles(ctx, r.config.Spec.GitHub.Owner, r.config.Spec.GitHub.Repository, event.GetNumber())
+	if err != nil {
+		return fmt.Errorf("list pull request files: %w", err)
+	}
+
+	// TODO: implement the real handling of the files
+	for _, file := range files {
+		// reference: https://docs.github.com/en/rest/commits/commits?apiVersion=2022-11-28#get-a-commit
+		switch file.GetStatus() {
+		case "added":
+			f, err := r.Read(ctx, logger, file.GetFilename(), file.GetSHA())
+			if err != nil {
+				r.logger.ErrorContext(ctx, "read added file", "file", file.GetFilename(), "error", err)
+				continue
+			}
+			r.logger.InfoContext(ctx, "added file", "file", file.GetFilename(), "resource", string(f.Data))
+		case "modified":
+			f, err := r.Read(ctx, logger, file.GetFilename(), file.GetSHA())
+			if err != nil {
+				r.logger.ErrorContext(ctx, "read modified file", "file", file.GetFilename(), "error", err)
+				continue
+			}
+			r.logger.InfoContext(ctx, "modified file", "file", file.GetFilename(), "resource", string(f.Data))
+		case "removed":
+			r.logger.InfoContext(ctx, "removed file", "file", file.GetFilename())
+		case "renamed":
+			r.logger.InfoContext(ctx, "renamed file", "file", file.GetFilename(), "previous", file.GetPreviousFilename())
+		case "changed":
+			f, err := r.Read(ctx, logger, file.GetFilename(), file.GetSHA())
+			if err != nil {
+				r.logger.ErrorContext(ctx, "read changed file", "file", file.GetFilename(), "error", err)
+				continue
+			}
+			r.logger.InfoContext(ctx, "changed file", "file", file.GetFilename(), "resource", string(f.Data))
+		case "unchanged":
+			r.logger.InfoContext(ctx, "ignore unchanged file", "file", file.GetFilename())
+		default:
+			r.logger.ErrorContext(ctx, "unhandled pull request file", "status", file.GetStatus(), "file", file.GetFilename())
+		}
+	}
+
+	commentTemplate := `Grafana detected that the following files have been changed in this pull request:
+{{range .}}
+- {{.GetFilename}} **{{.GetStatus }}**
+{{end}}
+`
+	tmpl, err := template.New("comment").Parse(commentTemplate)
+	if err != nil {
+		return fmt.Errorf("parse comment template: %w", err)
+	}
+
+	var buf bytes.Buffer
+	if err := tmpl.Execute(&buf, files); err != nil {
+		return fmt.Errorf("execute comment template: %w", err)
+	}
+
+	comment := buf.String()
+
+	if err := r.gh.CreatePullRequestComment(ctx, r.config.Spec.GitHub.Owner, r.config.Spec.GitHub.Repository, event.GetNumber(), comment); err != nil {
+		return fmt.Errorf("create pull request comment: %w", err)
+	}
+
+	r.logger.InfoContext(ctx, "comment created", "pull_request", event.GetNumber())
+
+	return nil
+}
+
 func (r *githubRepository) createWebhook(ctx context.Context, logger *slog.Logger) error {
 	cfg := pgh.WebhookConfig{
 		URL:         r.config.Spec.GitHub.WebhookURL,
 		Secret:      r.config.Spec.GitHub.WebhookSecret,
 		ContentType: "json",
-		Events:      []string{"push"},
+		Events:      []string{"push", "pull_request"},
 		Active:      true,
 	}
 

pkg/registry/apis/provisioning/repository/github/client.go

@@ -75,6 +75,9 @@ type Client interface {
 	CreateWebhook(ctx context.Context, owner, repository string, cfg WebhookConfig) error
 	DeleteWebhook(ctx context.Context, owner, repository string, webhookID int64) error
 	EditWebhook(ctx context.Context, owner, repository string, cfg WebhookConfig) error
+
+	ListPullRequestFiles(ctx context.Context, owner, repository string, number int) ([]CommitFile, error)
+	CreatePullRequestComment(ctx context.Context, owner, repository string, number int, body string) error
 }
 
 type RepositoryContent interface {
@@ -96,6 +99,13 @@ type RepositoryContent interface {
 	GetSize() int64
 }
 
+type CommitFile interface {
+	GetSHA() string
+	GetFilename() string
+	GetPreviousFilename() string
+	GetStatus() string
+}
+
 type CreateFileOptions struct {
 	// The message of the commit. May be empty, in which case a default value is entered.
 	Message string

pkg/registry/apis/provisioning/repository/github/client_mock.go

@@ -13,6 +13,34 @@ type MockClient struct {
 	mock.Mock
 }
 
+// BranchExists provides a mock function with given fields: ctx, owner, repository, branchName
+func (_m *MockClient) BranchExists(ctx context.Context, owner string, repository string, branchName string) (bool, error) {
+	ret := _m.Called(ctx, owner, repository, branchName)
+
+	if len(ret) == 0 {
+		panic("no return value specified for BranchExists")
+	}
+
+	var r0 bool
+	var r1 error
+	if rf, ok := ret.Get(0).(func(context.Context, string, string, string) (bool, error)); ok {
+		return rf(ctx, owner, repository, branchName)
+	}
+	if rf, ok := ret.Get(0).(func(context.Context, string, string, string) bool); ok {
+		r0 = rf(ctx, owner, repository, branchName)
+	} else {
+		r0 = ret.Get(0).(bool)
+	}
+
+	if rf, ok := ret.Get(1).(func(context.Context, string, string, string) error); ok {
+		r1 = rf(ctx, owner, repository, branchName)
+	} else {
+		r1 = ret.Error(1)
+	}
+
+	return r0, r1
+}
+
 // CreateBranch provides a mock function with given fields: ctx, owner, repository, sourceBranch, branchName
 func (_m *MockClient) CreateBranch(ctx context.Context, owner string, repository string, sourceBranch string, branchName string) error {
 	ret := _m.Called(ctx, owner, repository, sourceBranch, branchName)
@@ -31,26 +59,6 @@ func (_m *MockClient) CreateBranch(ctx context.Context, owner string, repository
 	return r0
 }
 
-func (_m *MockClient) BranchExists(ctx context.Context, owner string, repository string, branchName string) (bool, error) {
-	ret := _m.Called(ctx, owner, repository, branchName)
-	if len(ret) == 0 {
-		panic("no return value specified for BranchExists")
-	}
-	var r0 bool
-	if rf, ok := ret.Get(0).(func(context.Context, string, string, string) bool); ok {
-		r0 = rf(ctx, owner, repository, branchName)
-	} else {
-		r0 = ret.Bool(0)
-	}
-	var r1 error
-	if rf, ok := ret.Get(1).(func(context.Context, string, string, string) error); ok {
-		r1 = rf(ctx, owner, repository, branchName)
-	} else {
-		r1 = ret.Error(1)
-	}
-	return r0, r1
-}
-
 // CreateFile provides a mock function with given fields: ctx, owner, repository, path, branch, message, content
 func (_m *MockClient) CreateFile(ctx context.Context, owner string, repository string, path string, branch string, message string, content []byte) error {
 	ret := _m.Called(ctx, owner, repository, path, branch, message, content)
@@ -69,6 +77,24 @@ func (_m *MockClient) CreateFile(ctx context.Context, owner string, repository s
 	return r0
 }
 
+// CreatePullRequestComment provides a mock function with given fields: ctx, owner, repository, number, body
+func (_m *MockClient) CreatePullRequestComment(ctx context.Context, owner string, repository string, number int, body string) error {
+	ret := _m.Called(ctx, owner, repository, number, body)
+
+	if len(ret) == 0 {
+		panic("no return value specified for CreatePullRequestComment")
+	}
+
+	var r0 error
+	if rf, ok := ret.Get(0).(func(context.Context, string, string, int, string) error); ok {
+		r0 = rf(ctx, owner, repository, number, body)
+	} else {
+		r0 = ret.Error(0)
+	}
+
+	return r0
+}
+
 // CreateWebhook provides a mock function with given fields: ctx, owner, repository, cfg
 func (_m *MockClient) CreateWebhook(ctx context.Context, owner string, repository string, cfg WebhookConfig) error {
 	ret := _m.Called(ctx, owner, repository, cfg)
@@ -217,6 +243,36 @@ func (_m *MockClient) GetTree(ctx context.Context, owner string, repository stri
 	return r0, r1, r2
 }
 
+// ListPullRequestFiles provides a mock function with given fields: ctx, owner, repository, number
+func (_m *MockClient) ListPullRequestFiles(ctx context.Context, owner string, repository string, number int) ([]CommitFile, error) {
+	ret := _m.Called(ctx, owner, repository, number)
+
+	if len(ret) == 0 {
+		panic("no return value specified for ListPullRequestFiles")
+	}
+
+	var r0 []CommitFile
+	var r1 error
+	if rf, ok := ret.Get(0).(func(context.Context, string, string, int) ([]CommitFile, error)); ok {
+		return rf(ctx, owner, repository, number)
+	}
+	if rf, ok := ret.Get(0).(func(context.Context, string, string, int) []CommitFile); ok {
+		r0 = rf(ctx, owner, repository, number)
+	} else {
+		if ret.Get(0) != nil {
+			r0 = ret.Get(0).([]CommitFile)
+		}
+	}
+
+	if rf, ok := ret.Get(1).(func(context.Context, string, string, int) error); ok {
+		r1 = rf(ctx, owner, repository, number)
+	} else {
+		r1 = ret.Error(1)
+	}
+
+	return r0, r1
+}
+
 // ListWebhooks provides a mock function with given fields: ctx, owner, repository
 func (_m *MockClient) ListWebhooks(ctx context.Context, owner string, repository string) ([]WebhookConfig, error) {
 	ret := _m.Called(ctx, owner, repository)
@@ -270,8 +326,7 @@ func (_m *MockClient) UpdateFile(ctx context.Context, owner string, repository s
 func NewMockClient(t interface {
 	mock.TestingT
 	Cleanup(func())
-},
-) *MockClient {
+}) *MockClient {
 	mock := &MockClient{}
 	mock.Mock.Test(t)
 

pkg/registry/apis/provisioning/repository/github/real.go

@@ -310,6 +310,40 @@ func (r *realImpl) EditWebhook(ctx context.Context, owner, repository string, cf
 	return err
 }
 
+func (r *realImpl) ListPullRequestFiles(ctx context.Context, owner, repository string, number int) ([]CommitFile, error) {
+	commitFiles, _, err := r.gh.PullRequests.ListFiles(ctx, owner, repository, number, nil)
+	if err != nil {
+		var ghErr *github.ErrorResponse
+		if errors.As(err, &ghErr) && ghErr.Response.StatusCode == http.StatusServiceUnavailable {
+			return nil, ErrServiceUnavailable
+		}
+		return nil, err
+	}
+
+	ret := make([]CommitFile, 0, len(commitFiles))
+	for _, f := range commitFiles {
+		ret = append(ret, f)
+	}
+
+	return ret, nil
+}
+
+func (r *realImpl) CreatePullRequestComment(ctx context.Context, owner, repository string, number int, body string) error {
+	comment := &github.IssueComment{
+		Body: &body,
+	}
+
+	if _, _, err := r.gh.Issues.CreateComment(ctx, owner, repository, number, comment); err != nil {
+		var ghErr *github.ErrorResponse
+		if errors.As(err, &ghErr) && ghErr.Response.StatusCode == http.StatusServiceUnavailable {
+			return ErrServiceUnavailable
+		}
+		return err
+	}
+
+	return nil
+}
+
 type realRepositoryContent struct {
 	real *github.RepositoryContent
 }