metadata server

trigger/pubsub/util.go

@@ -1,15 +1,56 @@
 package pubsub
 
 import (
+	"io/ioutil"
+	"net/http"
 	"strings"
+
+	log "github.com/Sirupsen/logrus"
 )
 
+// MetadataEndpoint - default metadata server for gcloud pubsub
+const MetadataEndpoint = "metadata/computeMetadata/v1/instance/attributes/cluster-name"
+
 func containerRegistryURI(projectID, registry string) string {
 	return registry + "%2F" + projectID
 }
 
 func containerRegistrySubName(projectID, topic string) string {
-	return "keel-" + projectID + "-" + topic
+	cluster := "unknown"
+	clusterName, err := clusterName(MetadataEndpoint)
+	if err != nil {
+		log.WithFields(log.Fields{
+			"error":             err,
+			"metadata_endpoint": MetadataEndpoint,
+		}).Warn("trigger.pubsub.containerRegistrySubName: got error while retrieving cluster metadata, messages might be lost if more than one Keel instance is created")
+	} else {
+		cluster = clusterName
+	}
+
+	return "keel-" + cluster + "-" + projectID + "-" + topic
+}
+
+// https://cloud.google.com/compute/docs/storing-retrieving-metadata
+func clusterName(metadataEndpoint string) (string, error) {
+	req, err := http.NewRequest(http.MethodGet, metadataEndpoint, nil)
+	if err != nil {
+		return "", err
+	}
+
+	req.Header.Add("Metadata-Flavor", "Google")
+
+	client := &http.Client{}
+	resp, err := client.Do(req)
+	if err != nil {
+		return "", err
+	}
+	defer resp.Body.Close()
+	body, err := ioutil.ReadAll(resp.Body)
+	if err != nil {
+		return "", err
+	}
+
+	return string(body), nil
 }
 
 // isGoogleContainerRegistry - we only care about gcr.io images,