stackdriver: WIP - test retrieving project id from gce metadata

pkg/api/pluginproxy/ds_auth_provider.go

@@ -64,11 +64,33 @@ func ApplyRoute(ctx context.Context, req *http.Request, proxyPath string, route
 	}
 
 	if req.Header.Get("Authorization") == "" && ds.Type == "stackdriver" {
-		tokenSrc, err := google.DefaultTokenSource(ctx, "https://www.googleapis.com/auth/monitoring.read")
+		defaultCredentials, err := google.FindDefaultCredentials(ctx)
+		projectName := ds.JsonData.Get("defaultProject").MustString()
+		if projectName == "" {
+			ds.JsonData.Set("defaultProject", defaultCredentials.ProjectID)
+		}
+		if err != nil {
+			logger.Error("Failed to get default credentials", "error", err)
+		} else {
+			token, err := defaultCredentials.TokenSource.Token()
+			if err != nil {
+				logger.Error("Failed to get default access token", "error", err)
+			} else {
+				req.Header.Add("Authorization", fmt.Sprintf("Bearer %s", token.AccessToken))
+			}
+		}
+	}
+
+	if req.Header.Get("Authorization") == "" && ds.Type == "stackdriver" {
+		credentials, err := google.FindDefaultCredentials(ctx, "https://www.googleapis.com/auth/monitoring.read")
+		projectName := ds.JsonData.Get("defaultProject").MustString()
+		if projectName == "" {
+			ds.JsonData.Set("defaultProject", credentials.ProjectID)
+		}
 		if err != nil {
 			logger.Error("Failed to get access token", "error", err)
 		} else {
-			token, err := tokenSrc.Token()
+			token, err := credentials.TokenSource.Token()
 			if err != nil {
 				logger.Error("Failed to get access token", "error", err)
 			} else {

pkg/tsdb/stackdriver/stackdriver.go

@@ -15,6 +15,8 @@ import (
 	"strings"
 	"time"
 
+	"github.com/grafana/grafana/pkg/cmd/grafana-cli/logger"
+
 	"golang.org/x/net/context/ctxhttp"
 
 	"github.com/grafana/grafana/pkg/api/pluginproxy"
@@ -551,6 +553,7 @@ func (e *StackdriverExecutor) createRequest(ctx context.Context, dsInfo *models.
 		return nil, errors.New("Unable to find datasource plugin Stackdriver")
 	}
 	projectName := dsInfo.JsonData.Get("defaultProject").MustString()
+	logger.Info("projectName", "projectName", projectName)
 	proxyPass := fmt.Sprintf("stackdriver%s", "v3/projects/"+projectName+"/timeSeries")
 
 	var stackdriverRoute *plugins.AppPluginRoute