Milo: Buildbucket PubSub ingestion outline

milo/common/pubsub.go

+package common
+
+import (
+        "encoding/base64"
+        "fmt"
+        "net/url"
+        "strings"
+        "time"
+
+        "cloud.google.com/go/pubsub"
+        "golang.org/x/net/context"
+
+        "github.com/luci/gae/service/info"
+        "github.com/luci/luci-go/common/logging"
+        "github.com/luci/luci-go/milo/api/config"
+)
+
+type PubSubMessage struct {
+        Attributes map[string]string `json:"attributes"`
+        Data       string            `json:"data"`
+        MessageID  string            `json:"message_id"`
+}
+
+type PubSubSubscription struct {
+        Message      PubSubMessage `json:"message"`
+        Subscription string        `json:"subscription"`
+}
+
+// GetData returns the expanded form of Data (decoded from base64).
+func (m *PubSubSubscription) GetData() ([]byte, error) {
+        return base64.StdEncoding.DecodeString(m.Message.Data)
+}
+
+// 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 {
+                err := ensureBuildbucketSubscribed(c, settings.Buildbucket.Project)
+                return err
+        }
+        // TODO(hinoka): Ensure buildbot subscribed.
+        return nil
+}
+
+// ensureSubscribed is 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"

[Ryan Tseng, 2017/06/28 22:14:18]

This is hardcoded in the buildbucket code

+        if projectID == "" {
+                return fmt.Errorf("missing buildbucket project", projectID)
+        }
+        client, err := pubsub.NewClient(c, projectID)
+        if err != nil {
+                return err
+        }
+        // Check to see if the topic exists first.
+        topic := client.Topic(topicID)
+        if exists, err := topic.Exists(c); err != nil {
+                if strings.Contains(err.Error(), "PermissionDenied") {
+                        URL := "https://console.cloud.google.com/iam-admin/iam/project?project=" + projectID
+                        acct, serr := info.ServiceAccount(c)
+                        if serr != nil {
+                                acct = fmt.Sprintf("Unknown: %s", serr.Error())
+                        }
+                        // The documentation is incorrect.  The following permissions are needed:
+                        // PubSub Viewer - To view Topic (This action)
+                        // PubSub Editor - To subscribe to Topics (Below)
+                        // PubSub Subscriber does NOT allow viewing topics, and it does NOT
+                        // allow for attaching subscriptions to topics.
+                        logging.WithError(err).Errorf(
+                                c, "please go to %s and add %s as a Pub/Sub Editor", URL, acct)
+                } else {
+                        logging.WithError(err).Errorf(c, "could not check topic %#v", topic)
+                }
+                return err
+        } else if !exists {
+                err = fmt.Errorf("topic %#v does not exist", topic)
+                logging.Errorf(c, err.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.
+        pubsubModuleHost := "pubsub." + info.DefaultVersionHostname(c)
+        sub := client.Subscription(subID)
+        if exists, err := sub.Exists(c); err != nil {
+                logging.WithError(err).Errorf(c, "could not check subscription %#v", sub)
+                return err
+        } else if exists {
+                logging.Infof(c, "subscription %#v exists, no need to update", sub)
+                return nil
+        }
+        if err != nil {
+                logging.WithError(err).Errorf(c, "could not get hostname for pubsub module")
+                return err
+        }
+        endpointURL := url.URL{
+                Scheme: "https",
+                Host:   pubsubModuleHost,
+                Path:   "/_ah/push-handlers/buildbucket",
+        }
+        subConfig := pubsub.SubscriptionConfig{
+                Topic:       topic,
+                PushConfig:  pubsub.PushConfig{Endpoint: endpointURL.String()},
+                AckDeadline: time.Minute * 10,
+        }
+        newSub, err := client.CreateSubscription(c, subID, subConfig)
+        if err != nil {
+                if strings.Contains(err.Error(), "The supplied HTTP URL is not registered") {
+                        registerURL := "https://pantheon.corp.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 domain\n\n",
+                                verifyURL, registerURL, pubsubModuleHost)
+                } else {
+                        logging.WithError(err).Errorf(c, "could not create subscription %#v", sub)
+                }
+                return err
+        }
+        // Success!
+        logging.Infof(c, "successfully created subscription %#v", newSub)
+        return nil
+}