stackdriver: only get default token from metadata server when applying route

pkg/tsdb/stackdriver/test_datasource_query.go

+package stackdriver
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"io/ioutil"
+	"net/http"
+	"strings"
+
+	"github.com/grafana/grafana/pkg/cmd/grafana-cli/logger"
+	"github.com/grafana/grafana/pkg/components/simplejson"
+	"golang.org/x/net/context/ctxhttp"
+	"golang.org/x/oauth2/google"
+
+	"github.com/grafana/grafana/pkg/tsdb"
+)
+
+func (e *StackdriverExecutor) executeTestDataSource(ctx context.Context, tsdbQuery *tsdb.TsdbQuery) (*tsdb.Response, error) {
+	gceAutomaticAuthentication := e.dsInfo.JsonData.Get("gceAutomaticAuthentication").MustBool()
+	if gceAutomaticAuthentication {
+		defaultProject, err := e.getDefaultProject(ctx)
+		if err != nil {
+			return nil, err
+		}
+		e.dsInfo.JsonData.Set("defaultProject", defaultProject)
+	}
+
+	queryResult := &tsdb.QueryResult{Meta: simplejson.New(), RefId: tsdbQuery.Queries[0].RefId}
+	result := &tsdb.Response{
+		Results: make(map[string]*tsdb.QueryResult),
+	}
+
+	req, err := e.createRequest(ctx, e.dsInfo, "metricDescriptors")
+	if err != nil {
+		slog.Error("Failed to create request", "error", err)
+		return nil, fmt.Errorf("Failed to create request. error: %v", err)
+	}
+	res, err := ctxhttp.Do(ctx, e.httpClient, req)
+	if err != nil {
+		return nil, err
+	}
+
+	data, err := e.unmarshalMetricDescriptors(res)
+	if err != nil {
+		return nil, err
+	}
+
+	parts := strings.Split(req.URL.Path, "/")
+	defaultProject := parts[3]
+
+	table := transformMetricDescriptorResponseToTable(data)
+	queryResult.Tables = append(queryResult.Tables, table)
+	result.Results[tsdbQuery.Queries[0].RefId] = queryResult
+	result.Results[tsdbQuery.Queries[0].RefId].Meta.Set("defaultProject", defaultProject)
+
+	return result, nil
+}
+
+func (e *StackdriverExecutor) getDefaultProject(ctx context.Context) (string, error) {
+	defaultCredentials, err := google.FindDefaultCredentials(ctx, "https://www.googleapis.com/auth/monitoring.read")
+	if err != nil {
+		return "", err
+	} else {
+		logger.Info("projectName", "projectName", defaultCredentials.ProjectID)
+		return defaultCredentials.ProjectID, nil
+	}
+}
+
+func transformMetricDescriptorResponseToTable(data MetricDescriptorsResponse) *tsdb.Table {
+	table := &tsdb.Table{
+		Columns: make([]tsdb.TableColumn, 1),
+		Rows:    make([]tsdb.RowValues, 0),
+	}
+	table.Columns[0].Text = "metricDescriptor"
+
+	for _, r := range data.MetricDescriptors {
+		values := make([]interface{}, 1)
+		values[0] = r
+		table.Rows = append(table.Rows, values)
+	}
+	return table
+}
+
+func (e *StackdriverExecutor) unmarshalMetricDescriptors(res *http.Response) (MetricDescriptorsResponse, error) {
+	body, err := ioutil.ReadAll(res.Body)
+	defer res.Body.Close()
+	if err != nil {
+		return MetricDescriptorsResponse{}, err
+	}
+
+	if res.StatusCode/100 != 2 {
+		slog.Error("Request failed", "status", res.Status, "body", string(body))
+		return MetricDescriptorsResponse{}, fmt.Errorf(`%s`, string(body))
+	}
+
+	var data MetricDescriptorsResponse
+	err = json.Unmarshal(body, &data)
+	if err != nil {
+		slog.Error("Failed to unmarshal MetricDescriptorResponse", "error", err, "status", res.Status, "body", string(body))
+		return MetricDescriptorsResponse{}, err
+	}
+
+	return data, nil
+}