GT-127 Add support for Metrics. Deprecate statistics (#440)

Author: jwierzbo

CHANGELOG.md

@@ -17,6 +17,7 @@
 - Add tests to check support for Enterprise Graphs
 - Search View v2 (`search-alias`)
 - Add Rename View support
+- Add support for `Metrics`
 
 ## [1.3.3](https://github.com/arangodb/go-driver/tree/v1.3.3) (2022-07-27)
 - Fix `lastValue` field type

client_server_admin.go

@@ -38,6 +38,26 @@ type ClientServerAdmin interface {
 	// Shutdown a specific server, optionally removing it from its cluster.
 	Shutdown(ctx context.Context, removeFromCluster bool) error
 
+	// Metrics returns the metrics of the server in Prometheus format.
+	// List of metrics: https://www.arangodb.com/docs/devel/http/administration-and-monitoring-metrics.html
+	// You can parse it using Prometheus client:
+	/*
+		var parser expfmt.TextParser
+		metricsProm, err := parser.TextToMetricFamilies(strings.NewReader(string(metrics)))
+	*/
+	Metrics(ctx context.Context) ([]byte, error)
+
+	// MetricsForSingleServer returns the metrics of the specific server in Prometheus format.
+	// This parameter 'serverID' is only meaningful on Coordinators.
+	// List of metrics: https://www.arangodb.com/docs/devel/http/administration-and-monitoring-metrics.html
+	// You can parse it using Prometheus client:
+	/*
+		var parser expfmt.TextParser
+		metricsProm, err := parser.TextToMetricFamilies(strings.NewReader(string(metrics)))
+	*/
+	MetricsForSingleServer(ctx context.Context, serverID string) ([]byte, error)
+
+	// Deprecated: Use Metrics instead.
 	// Statistics queries statistics from a specific server
 	Statistics(ctx context.Context) (ServerStatistics, error)
 

client_server_admin_impl.go

@@ -142,6 +142,41 @@ func (c *client) Shutdown(ctx context.Context, removeFromCluster bool) error {
 	return nil
 }
 
+// Metrics returns the metrics of the server in Prometheus format.
+func (c *client) Metrics(ctx context.Context) ([]byte, error) {
+	return c.getMetrics(ctx, "")
+}
+
+// MetricsForSingleServer returns the metrics of the specific server in Prometheus format.
+// This parameter 'serverID' is only meaningful on Coordinators.
+func (c *client) MetricsForSingleServer(ctx context.Context, serverID string) ([]byte, error) {
+	return c.getMetrics(ctx, serverID)
+}
+
+// Metrics returns the metrics of the server in Prometheus format.
+func (c *client) getMetrics(ctx context.Context, serverID string) ([]byte, error) {
+	var rawResponse []byte
+	ctx = WithRawResponse(ctx, &rawResponse)
+
+	req, err := c.conn.NewRequest("GET", "_admin/metrics/v2")
+	if err != nil {
+		return rawResponse, WithStack(err)
+	}
+
+	if serverID != "" {
+		req.SetQuery("serverId", serverID)
+	}
+
+	resp, err := c.conn.Do(ctx, req)
+	if err != nil {
+		return rawResponse, WithStack(err)
+	}
+	if err := resp.CheckStatus(200); err != nil {
+		return rawResponse, WithStack(err)
+	}
+	return rawResponse, nil
+}
+
 // Statistics queries statistics from a specific server.
 func (c *client) Statistics(ctx context.Context) (ServerStatistics, error) {
 	req, err := c.conn.NewRequest("GET", "_admin/statistics")

http/connection.go

@@ -270,8 +270,10 @@ func (c *httpConnection) Do(ctx context.Context, req driver.Request) (driver.Res
 		return nil, driver.WithStack(err)
 	}
 	var rawResponse *[]byte
+	useRawResponse := false
 	if ctx != nil {
 		if v := ctx.Value(keyRawResponse); v != nil {
+			useRawResponse = true
 			if buf, ok := v.(*[]byte); ok {
 				rawResponse = buf
 			}
@@ -310,6 +312,8 @@ func (c *httpConnection) Do(ctx context.Context, req driver.Request) (driver.Res
 				*rawResponse = body
 			}
 			httpResp = &httpJSONResponse{resp: resp, rawResponse: body}
+		} else if useRawResponse {
+			httpResp = &httpJSONResponse{resp: resp, rawResponse: body}
 		} else {
 			return nil, driver.WithStack(fmt.Errorf("Unsupported content type '%s' with status %d and content '%s'", ct, resp.StatusCode, string(body)))
 		}

test/server_metrics_test.go

@@ -0,0 +1,63 @@
+//
+// DISCLAIMER
+//
+// Copyright 2018 ArangoDB GmbH, Cologne, Germany
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+// Copyright holder is ArangoDB GmbH, Cologne, Germany
+
+package test
+
+import (
+	"context"
+	"testing"
+
+	"github.com/arangodb/go-driver"
+
+	"github.com/stretchr/testify/require"
+)
+
+// TestGetServerMetrics tests if Client.Metrics works at all
+func TestGetServerMetrics(t *testing.T) {
+	c := createClientFromEnv(t, true)
+	ctx := context.Background()
+	skipBelowVersion(c, "3.8", t)
+
+	metrics, err := c.Metrics(ctx)
+	require.NoError(t, err)
+	require.Contains(t, string(metrics), "arangodb_client_connection_statistics_total_time")
+}
+
+// TestGetServerMetricsForSingleServer tests if Client.MetricsForSingleServer works at all
+func TestGetServerMetricsForSingleServer(t *testing.T) {
+	c := createClientFromEnv(t, true)
+	ctx := context.Background()
+	skipBelowVersion(c, "3.8", t)
+	skipNoCluster(c, t)
+
+	cl, err := c.Cluster(ctx)
+	require.NoError(t, err)
+
+	h, err := cl.Health(ctx)
+	require.NoError(t, err)
+
+	for id, sh := range h.Health {
+		if sh.Role == driver.ServerRoleDBServer || sh.Role == driver.ServerRoleCoordinator {
+			metrics, err := c.MetricsForSingleServer(ctx, string(id))
+			require.NoError(t, err)
+			require.Contains(t, string(metrics), "arangodb_client_connection_statistics_total_time")
+			require.Contains(t, string(metrics), sh.ShortName)
+		}
+	}
+}