feat: impl cherrypicker (#451)

.codecov.yml

@@ -5,5 +5,5 @@ coverage:
   status:
     project:
       default:
-        # Fail the status if coverage drops by >= 1%
+        # Fail the status if coverage drops by >= 5%
         threshold: 1

.goreleaser.yml

@@ -88,6 +88,15 @@ builds:
     main: ./cmd/ticommunitycontribution/main.go
     env:
       - CGO_ENABLED=0
+  - id: "ti-community-cherrypicker"
+    binary: ticommunitycherrypicker
+    goos:
+      - linux
+    goarch:
+      - amd64
+    main: ./cmd/ticommunitycherrypicker/main.go
+    env:
+      - CGO_ENABLED=0
   - id: "check-external-plugin-config"
     binary: check-external-plugin-config
     goos:
@@ -203,6 +212,15 @@ dockers:
       - "ticommunityinfra/tichi-contribution-plugin:{{ .Tag }}"
       - "ticommunityinfra/tichi-contribution-plugin:{{ .Major }}"
     dockerfile: ./deployments/plugins/contribution/Dockerfile
+  - binaries:
+      - ticommunitycherrypicker
+    builds:
+      - ti-community-cherrypicker
+    image_templates:
+      - "ticommunityinfra/tichi-cherrypicker-plugin:latest"
+      - "ticommunityinfra/tichi-cherrypicker-plugin:{{ .Tag }}"
+      - "ticommunityinfra/tichi-cherrypicker-plugin:{{ .Major }}"
+    dockerfile: ./deployments/plugins/cherrypicker/Dockerfile
   -
     image_templates:
       - "ticommunityinfra/tichi-web:latest"

cmd/ticommunitycherrypicker/main.go

@@ -0,0 +1,139 @@
+package main
+
+import (
+	"flag"
+	"fmt"
+	"net/http"
+	"os"
+	"strconv"
+	"time"
+
+	"github.com/sirupsen/logrus"
+	tiexternalplugins "github.com/ti-community-infra/tichi/internal/pkg/externalplugins"
+	"github.com/ti-community-infra/tichi/internal/pkg/externalplugins/cherrypicker"
+	"k8s.io/test-infra/pkg/flagutil"
+	"k8s.io/test-infra/prow/config/secret"
+	prowflagutil "k8s.io/test-infra/prow/flagutil"
+	"k8s.io/test-infra/prow/git/v2"
+	"k8s.io/test-infra/prow/interrupts"
+	"k8s.io/test-infra/prow/pjutil"
+	"k8s.io/test-infra/prow/pluginhelp/externalplugins"
+)
+
+type options struct {
+	port int
+
+	dryRun bool
+	github prowflagutil.GitHubOptions
+
+	externalPluginsConfig string
+
+	webhookSecretFile string
+}
+
+// validate validates github options.
+func (o *options) validate() error {
+	for idx, group := range []flagutil.OptionGroup{&o.github} {
+		if err := group.Validate(o.dryRun); err != nil {
+			return fmt.Errorf("%d: %w", idx, err)
+		}
+	}
+
+	return nil
+}
+
+func gatherOptions() options {
+	o := options{}
+	fs := flag.NewFlagSet(os.Args[0], flag.ExitOnError)
+	fs.IntVar(&o.port, "port", 80, "Port to listen on.")
+	fs.StringVar(&o.externalPluginsConfig, "external-plugins-config",
+		"/etc/external_plugins_config/external_plugins_config.yaml", "Path to external plugin config file.")
+	fs.BoolVar(&o.dryRun, "dry-run", true, "Dry run for testing. Uses API tokens but does not mutate.")
+	fs.StringVar(&o.webhookSecretFile, "hmac-secret-file",
+		"/etc/webhook/hmac", "Path to the file containing the GitHub HMAC secret.")
+
+	for _, group := range []flagutil.OptionGroup{&o.github} {
+		group.AddFlags(fs)
+	}
+	_ = fs.Parse(os.Args[1:])
+	return o
+}
+
+func main() {
+	o := gatherOptions()
+	if err := o.validate(); err != nil {
+		logrus.Fatalf("Invalid options: %v", err)
+	}
+
+	log := logrus.StandardLogger().WithField("plugin", cherrypicker.PluginName)
+
+	epa := &tiexternalplugins.ConfigAgent{}
+	if err := epa.Start(o.externalPluginsConfig, false); err != nil {
+		log.WithError(err).Fatalf("Error loading external plugin config from %q.", o.externalPluginsConfig)
+	}
+
+	secretAgent := &secret.Agent{}
+	if err := secretAgent.Start([]string{o.github.TokenPath, o.webhookSecretFile}); err != nil {
+		logrus.WithError(err).Fatal("Error starting secrets agent.")
+	}
+
+	githubClient, err := o.github.GitHubClient(secretAgent, o.dryRun)
+	if err != nil {
+		logrus.WithError(err).Fatal("Error getting GitHub client.")
+	}
+	githubClient.Throttle(360, 360)
+
+	gitClient, err := o.github.GitClient(secretAgent, o.dryRun)
+	if err != nil {
+		logrus.WithError(err).Fatal("Error getting Git client.")
+	}
+	interrupts.OnInterrupt(func() {
+		if err := gitClient.Clean(); err != nil {
+			logrus.WithError(err).Error("Could not clean up git client cache.")
+		}
+	})
+
+	email, err := githubClient.Email()
+	if err != nil {
+		log.WithError(err).Fatal("Error getting bot e-mail.")
+	}
+
+	botUser, err := githubClient.BotUser()
+	if err != nil {
+		logrus.WithError(err).Fatal("Error getting bot name.")
+	}
+
+	repos, err := githubClient.GetRepos(botUser.Login, true)
+	if err != nil {
+		log.WithError(err).Fatal("Error listing bot repositories.")
+	}
+
+	server := &cherrypicker.Server{
+		TokenGenerator: secretAgent.GetTokenGenerator(o.webhookSecretFile),
+		BotUser:        botUser,
+		Email:          email,
+		ConfigAgent:    epa,
+
+		GitClient:    git.ClientFactoryFrom(gitClient),
+		GitHubClient: githubClient,
+		Log:          log,
+
+		Bare:     &http.Client{},
+		PatchURL: "https://patch-diff.githubusercontent.com",
+
+		Repos: repos,
+	}
+
+	health := pjutil.NewHealth()
+	health.ServeReady()
+
+	mux := http.NewServeMux()
+	mux.Handle("/", server)
+
+	helpProvider := cherrypicker.HelpProvider(epa)
+	externalplugins.ServeExternalPluginHelp(mux, log, helpProvider)
+	httpServer := &http.Server{Addr: ":" + strconv.Itoa(o.port), Handler: mux}
+
+	defer interrupts.WaitForGracefulShutdown()
+	interrupts.ListenAndServe(httpServer, 5*time.Second)
+}

deployments/plugins/cherrypicker/Dockerfile

@@ -0,0 +1,4 @@
+FROM alpine:3.12
+ADD ticommunitycherrypicker /usr/local/bin/
+EXPOSE 80
+ENTRYPOINT ["/usr/local/bin/ticommunitycherrypicker"]