use ReleaseHistory Tiller GRPC call to check state

Switches to using the ReleaseHistory GRPC call to see if the chart
release exists or not. If it doesn't exist, install the chart, otherwise
upgrade it.

cmd/controller/controller.go

@@ -162,7 +162,7 @@ func releaseName(ns, name string) string {
 func isNotFound(err error) bool {
 	// Ideally this would be `grpc.Code(err) == codes.NotFound`,
 	// but it seems helm doesn't return grpc codes
-	return strings.Contains(grpc.ErrorDesc(err), "has no deployed releases")
+	return strings.Contains(grpc.ErrorDesc(err), "not found")
 }
 
 func (c *Controller) updateRelease(key string) error {
@@ -230,19 +230,12 @@ func (c *Controller) updateRelease(key string) error {
 
 	var rel *release.Release
 
-	log.Printf("Updating release %s", rlsName)
-	res, err := c.helmClient.UpdateReleaseFromChart(
-		rlsName,
-		chartRequested,
-		helm.UpdateValueOverrides([]byte(helmObj.Spec.Values)),
-		//helm.UpgradeForce(true), ?
-	)
+	_, err = c.helmClient.ReleaseHistory(rlsName, helm.WithMaxHistory(1))
 	if err != nil {
 		if !isNotFound(err) {
 			return err
 		}
-
-		log.Printf("Existing release %s not found -> installing into namespace %s", rlsName, helmObj.Namespace)
+		log.Printf("Installing release %s into namespace %s", rlsName, helmObj.Namespace)
 		res, err := c.helmClient.InstallReleaseFromChart(
 			chartRequested,
 			helmObj.Namespace,
@@ -254,6 +247,16 @@ func (c *Controller) updateRelease(key string) error {
 		}
 		rel = res.GetRelease()
 	} else {
+		log.Printf("Updating release %s", rlsName)
+		res, err := c.helmClient.UpdateReleaseFromChart(
+			rlsName,
+			chartRequested,
+			helm.UpdateValueOverrides([]byte(helmObj.Spec.Values)),
+			//helm.UpgradeForce(true), ?
+		)
+		if err != nil {
+			return err
+		}
 		rel = res.GetRelease()
 	}