Milo: Move buildbucket pubsub sub from buildbucket project to milo project

milo/common/pubsub.go

Index: milo/common/pubsub.go
diff --git a/milo/common/pubsub.go b/milo/common/pubsub.go
index 56b79c2b05902c61395af9853b59294f0865550e..56ec5c5c963a92740124d1d1b9115fb846d0ca64 100644
--- a/milo/common/pubsub.go
+++ b/milo/common/pubsub.go
@@ -2,7 +2,6 @@ package common
 
 import (
 	"encoding/base64"
-	"errors"
 	"fmt"
 	"net/url"
 	"strings"
@@ -12,11 +11,12 @@ import (
 	"golang.org/x/net/context"
 
 	"github.com/luci/gae/service/info"
+	"github.com/luci/luci-go/common/errors"
 	"github.com/luci/luci-go/common/logging"
 	"github.com/luci/luci-go/milo/api/config"
 )
 
-var pubSubClientKey = "stores a pubsubClient"
+var pubsubClientFactoryKey = "stores a pubsubClientFactory"
 
 type PubSubMessage struct {
 	Attributes map[string]string `json:"attributes"`
@@ -42,25 +42,28 @@ func (m *PubSubSubscription) GetData() ([]byte, error) {
 type pubsubClient interface {
 	// getTopic returns the pubsub topic if it exists, a notExist error if
 	// it does not exist, or an error if there was an error.
-	getTopic(string) (*pubsub.Topic, error)
+	getTopic(context.Context, string) (*pubsub.Topic, error)
 
 	// getSubscription returns the pubsub subscription if it exists,
 	// a notExist error if it does not exist, or an error if there was an error.
-	getSubscription(string) (*pubsub.Subscription, error)
+	getSubscription(context.Context, string) (*pubsub.Subscription, error)
 
-	createSubscription(string, pubsub.SubscriptionConfig) (
+	createSubscription(context.Context, string, pubsub.SubscriptionConfig) (
 		*pubsub.Subscription, error)
 }
 
+// pubsubClientFactory is a stubbable factory that produces pubsubClients bound
+// to project IDs.
+type pubsubClientFactory func(context.Context, string) (pubsubClient, error)
+
 // prodPubSubClient is a wrapper around the production pubsub client.
 type prodPubSubClient struct {
-	ctx    context.Context
-	client *pubsub.Client
+	*pubsub.Client
 }
 
-func (pc *prodPubSubClient) getTopic(id string) (*pubsub.Topic, error) {
-	topic := pc.client.Topic(id)
-	exists, err := topic.Exists(pc.ctx)
+func (pc *prodPubSubClient) getTopic(c context.Context, id string) (*pubsub.Topic, error) {
+	topic := pc.Client.Topic(id)
+	exists, err := topic.Exists(c)
 	switch {
 	case err != nil:
 		return nil, err
@@ -70,9 +73,9 @@ func (pc *prodPubSubClient) getTopic(id string) (*pubsub.Topic, error) {
 	return topic, nil
 }
 
-func (pc *prodPubSubClient) getSubscription(id string) (*pubsub.Subscription, error) {
-	sub := pc.client.Subscription(id)
-	exists, err := sub.Exists(pc.ctx)
+func (pc *prodPubSubClient) getSubscription(c context.Context, id string) (*pubsub.Subscription, error) {
+	sub := pc.Client.Subscription(id)
+	exists, err := sub.Exists(c)
 	switch {
 	case err != nil:
 		return nil, err
@@ -82,85 +85,55 @@ func (pc *prodPubSubClient) getSubscription(id string) (*pubsub.Subscription, er
 	return sub, nil
 }
 
-func (pc *prodPubSubClient) createSubscription(id string, cfg pubsub.SubscriptionConfig) (
+func (pc *prodPubSubClient) createSubscription(
+	c context.Context, id string, cfg pubsub.SubscriptionConfig) (
 	*pubsub.Subscription, error) {
 
-	return pc.client.CreateSubscription(pc.ctx, id, cfg)
-}
-
-// getPubSubClient extracts a debug PubSub client out of the context.
-func getPubSubClient(c context.Context) (pubsubClient, error) {
-	if client, ok := c.Value(&pubSubClientKey).(pubsubClient); ok {
-		return client, nil
-	}
-	return nil, errors.New("no pubsub clients installed")
-}
-
-// withClient returns a context with a pubsub client instantiated to the
-// given project ID
-func withClient(c context.Context, projectID string) (context.Context, error) {
-	if projectID == "" {
-		return nil, errors.New("missing buildbucket project")
-	}
-	client, err := pubsub.NewClient(c, projectID)
-	if err != nil {
-		return nil, err
-	}
-	return context.WithValue(c, &pubSubClientKey, &prodPubSubClient{c, client}), nil
+	return pc.Client.CreateSubscription(c, id, cfg)
 }
 
-func getTopic(c context.Context, id string) (*pubsub.Topic, error) {
-	client, err := getPubSubClient(c)
-	if err != nil {
-		return nil, err
-	}
-	return client.getTopic(id)
+func prodPubSubClientFactory(c context.Context, projectID string) (pubsubClient, error) {
+	cli, err := pubsub.NewClient(c, projectID)
+	return &prodPubSubClient{cli}, err
 }
 
-func getSubscription(c context.Context, id string) (*pubsub.Subscription, error) {
-	client, err := getPubSubClient(c)
-	if err != nil {
-		return nil, err
-	}
-	return client.getSubscription(id)
+// withClientFactory returns a context with a given pubsub client factory.
+func withClientFactory(c context.Context, fac pubsubClientFactory) context.Context {
+	return context.WithValue(c, &pubsubClientFactoryKey, fac)
 }
 
-func createSubscription(c context.Context, id string, cfg pubsub.SubscriptionConfig) (
-	*pubsub.Subscription, error) {
-
-	client, err := getPubSubClient(c)
-	if err != nil {
-		return nil, err
+func newPubSubClient(c context.Context, projectID string) (pubsubClient, error) {
+	if fac, ok := c.Value(&pubsubClientFactoryKey).(pubsubClientFactory); !ok {
+		panic("no pubsub client factory installed")
+	} else {
+		return fac(c, projectID)
 	}
-	return client.createSubscription(id, cfg)
 }
 
 // EnsurePubSubSubscribed makes sure the following subscriptions are in place:
 // * buildbucket, via the settings.Buildbucket.Topic setting
 func EnsurePubSubSubscribed(c context.Context, settings *config.Settings) error {
 	if settings.Buildbucket != nil {
-		// Install the production pubsub client pointing to the buildbucket project
-		// into the context.
-		c, err := withClient(c, settings.Buildbucket.Project)
-		if err != nil {
-			return err
-		}
+		c = withClientFactory(c, prodPubSubClientFactory)
 		return ensureBuildbucketSubscribed(c, settings.Buildbucket.Project)
 	}
 	// TODO(hinoka): Ensure buildbot subscribed.
 	return nil
 }
 
-// ensureSubscribed is called by a cron job and ensures that the Milo
+// ensureBuildbucketSubscribedis called by a cron job and ensures that the Milo
 // instance is properly subscribed to the buildbucket subscription endpoint.
 func ensureBuildbucketSubscribed(c context.Context, projectID string) error {
 	topicID := "builds"
-	// Check to see if the topic exists first.
-	topic, err := getTopic(c, topicID)
+	// Check the buildbucket project to see if the topic exists first.
+	bbClient, err := newPubSubClient(c, projectID)
+	if err != nil {
+		return err
+	}
+	topic, err := bbClient.getTopic(c, topicID)
 	switch err {
 	case errNotExist:
-		logging.WithError(err).Errorf(c, "%s does not exist", topicID)
-		return err
+		return errors.Annotate(err, "%s does not exist", topicID).Err()
 	case nil:
 		// continue
 	default:
@@ -181,10 +154,11 @@ func ensureBuildbucketSubscribed(c context.Context, projectID string) error {
 		return err
 	}
 	// Now check to see if the subscription already exists.
-	subID := info.AppID(c)
-	// Get the pubsub module of our app.  We do not want to use info.ModuleHostname()
-	// because it returns a version pinned hostname instead of the default route.
-	sub, err := getSubscription(c, subID)
+	miloClient, err := newPubSubClient(c, info.AppID(c))
+	if err != nil {
+		return err
+	}
+	sub, err := miloClient.getSubscription(c, "buildbucket")
 	switch err {
 	case errNotExist:
 		// continue
@@ -195,6 +169,8 @@ func ensureBuildbucketSubscribed(c context.Context, projectID string) error {
 		logging.WithError(err).Errorf(c, "could not check subscription %#v", sub)
 		return err
 	}
+	// Get the pubsub module of our app.  We do not want to use info.ModuleHostname()
+	// because it returns a version pinned hostname instead of the default route.
 	pubsubModuleHost := "pubsub." + info.DefaultVersionHostname(c)
 
 	// No subscription exists, attach a new subscription to the existing topic.
@@ -208,22 +184,9 @@ func ensureBuildbucketSubscribed(c context.Context, projectID string) error {
 		PushConfig:  pubsub.PushConfig{Endpoint: endpointURL.String()},
 		AckDeadline: time.Minute * 10,
 	}
-	newSub, err := createSubscription(c, subID, subConfig)
+	newSub, err := miloClient.createSubscription(c, "buildbucket", subConfig)
 	if err != nil {
-		if strings.Contains(err.Error(), "The supplied HTTP URL is not registered") {
-			registerURL := "https://console.cloud.google.com/apis/credentials/domainverification?project=" + projectID
-			verifyURL := "https://www.google.com/webmasters/verification/verification?hl=en-GB&siteUrl=http://" + pubsubModuleHost
-			logging.WithError(err).Errorf(
-				c, "The domain has to be verified and added.\n\n"+
-					"1. Go to %s\n"+
-					"2. Verify the domain\n"+
-					"3. Go to %s\n"+
-					"4. Add %s to allowed domains\n\n",
-				verifyURL, registerURL, pubsubModuleHost)
-		} else {
-			logging.WithError(err).Errorf(c, "could not create subscription %#v", sub)
-		}
-		return err
+		return errors.Annotate(err, "could not create subscription %#v", sub).Err()
 	}
 	// Success!
 	logging.Infof(c, "successfully created subscription %#v", newSub)