optionally expose expvar

CHANGELOG.asciidoc

@@ -40,6 +40,7 @@ https://github.com/elastic/apm-server/compare/71df0d96445df35afe27f38bcf734a0828
 - Add Kibana sourcefilter for `sourcemap.sourcemap` {pull}454[454]
 - Increase default 'ConcurrentRequests' from 20 to 40{pull}492[492]
 - Add Config option for excluding stack trace frames from `grouping_key` calculation {pull}482[482]
+- Expose expvar {pull}509[509]
 
 ==== Deprecated
 

_meta/beat.reference.yml

@@ -69,3 +69,11 @@ apm-server:
       # If the default index pattern at 'outputs.elasticsearch.index' is changed,
       # a matching index pattern needs to be specified here.
       #index_pattern: "apm-*"
+
+  # golang expvar support - https://golang.org/pkg/expvar/
+  #expvar:
+  # Set to true to Expose expvar
+  #enabled: false
+
+  # Url to expose expvar
+  #url: "/debug/vars"

apm-server.reference.yml

@@ -70,6 +70,14 @@ apm-server:
       # a matching index pattern needs to be specified here.
       #index_pattern: "apm-*"
 
+  # golang expvar support - https://golang.org/pkg/expvar/
+  #expvar:
+  # Set to true to Expose expvar
+  #enabled: false
+
+  # Url to expose expvar
+  #url: "/debug/vars"
+
 #================================ General ======================================
 
 # The name of the shipper that publishes the network data. It can be used to group

beater/beater_test.go

@@ -49,6 +49,10 @@ func TestBeatConfig(t *testing.T) {
 					"certificate": "1234cert",
 				},
 				"concurrent_requests": 15,
+				"expvar": map[string]interface{}{
+					"enabled": true,
+					"url":     "/debug/vars",
+				},
 				"frontend": map[string]interface{}{
 					"enabled":       true,
 					"rate_limit":    1000,
@@ -72,6 +76,10 @@ func TestBeatConfig(t *testing.T) {
 				ShutdownTimeout: 9000000000,
 				SecretToken:     "1234random",
 				SSL:             &SSLConfig{Enabled: &truthy, PrivateKey: "1234key", Cert: "1234cert"},
+				Expvar: &ExpvarConfig{
+					Enabled: &truthy,
+					Url:     "/debug/vars",
+				},
 				Frontend: &FrontendConfig{
 					Enabled:      &truthy,
 					RateLimit:    1000,
@@ -95,6 +103,10 @@ func TestBeatConfig(t *testing.T) {
 				"ssl": map[string]interface{}{
 					"enabled": true,
 				},
+				"expvar": map[string]interface{}{
+					"enabled": true,
+					"url":     "/debug/vars",
+				},
 				"frontend": map[string]interface{}{
 					"enabled": true,
 					"source_mapping": map[string]interface{}{
@@ -113,6 +125,10 @@ func TestBeatConfig(t *testing.T) {
 				ShutdownTimeout: 5000000000,
 				SecretToken:     "1234random",
 				SSL:             &SSLConfig{Enabled: &truthy, PrivateKey: "", Cert: ""},
+				Expvar: &ExpvarConfig{
+					Enabled: &truthy,
+					Url:     "/debug/vars",
+				},
 				Frontend: &FrontendConfig{
 					Enabled:      &truthy,
 					RateLimit:    10,

beater/config.go

@@ -17,9 +17,15 @@ type Config struct {
 	SecretToken        string          `config:"secret_token"`
 	SSL                *SSLConfig      `config:"ssl"`
 	ConcurrentRequests int             `config:"concurrent_requests" validate:"min=1"`
+	Expvar             *ExpvarConfig   `config:"expvar"`
 	Frontend           *FrontendConfig `config:"frontend"`
 }
 
+type ExpvarConfig struct {
+	Enabled *bool  `config:"enabled"`
+	Url     string `config:"url"`
+}
+
 type FrontendConfig struct {
 	Enabled             *bool          `config:"enabled"`
 	RateLimit           int            `config:"rate_limit"`
@@ -57,6 +63,10 @@ func (c *SSLConfig) isEnabled() bool {
 	return c != nil && (c.Enabled == nil || *c.Enabled)
 }
 
+func (c *ExpvarConfig) isEnabled() bool {
+	return c != nil && (c.Enabled == nil || *c.Enabled)
+}
+
 func (c *FrontendConfig) isEnabled() bool {
 	return c != nil && (c.Enabled == nil || *c.Enabled)
 }
@@ -109,5 +119,9 @@ func defaultConfig() *Config {
 			LibraryPattern:      "node_modules|bower_components|~",
 			ExcludeFromGrouping: "^/webpack",
 		},
+		Expvar: &ExpvarConfig{
+			Enabled: new(bool),
+			Url:     "/debug/vars",
+		},
 	}
 }

beater/handlers.go

@@ -6,6 +6,7 @@ import (
 	"context"
 	"crypto/subtle"
 	"encoding/json"
+	"expvar"
 	"fmt"
 	"net"
 	"net/http"
@@ -81,6 +82,11 @@ func newMuxer(config *Config, report reporter) *http.ServeMux {
 		mux.Handle(path, mapping.ProcessorHandler(mapping.ProcessorFactory, config, report))
 	}
 
+	if config.Expvar.isEnabled() {
+		path := config.Expvar.Url
+		logp.Info("Path %s added to request handler", path)
+		mux.Handle(path, expvar.Handler())
+	}
 	return mux
 }
 

tests/system/apmserver.py

@@ -1,7 +1,8 @@
-import sys
-import os
 import json
+import os
 import shutil
+import sys
+
 sys.path.append('../../_beats/libbeat/tests/system')
 from beat.beat import TestCase
 from elasticsearch import Elasticsearch
@@ -45,9 +46,9 @@ def get_error_payload(self):
 
 
 class ServerSetUpBaseTest(BaseTest):
-
     transactions_url = 'http://localhost:8200/v1/transactions'
     errors_url = 'http://localhost:8200/v1/errors'
+    expvar_url = 'http://localhost:8200/debug/vars'
 
     def config(self):
         return {"ssl_enabled": "false",
@@ -300,3 +301,15 @@ def config(self):
         cfg = super(SmapCacheBaseTest, self).config()
         cfg.update({"smap_cache_expiration": "1"})
         return cfg
+
+
+class ExpvarBaseTest(ServerBaseTest):
+    config_overrides = {}
+
+    def config(self):
+        cfg = super(ServerBaseTest, self).config()
+        cfg.update(self.config_overrides)
+        return cfg
+
+    def get_debug_vars(self):
+        return requests.get(self.expvar_url)

tests/system/config/apm-server.yml.j2

@@ -17,6 +17,12 @@ apm-server:
   frontend.source_mapping.index_pattern: {{ smap_index_pattern}}
   frontend.source_mapping.cache.expiration: {{ smap_cache_expiration}}
   {% endif %}
+  {% if expvar_enabled %}
+  expvar.enabled: {{ expvar_enabled }}
+  {% endif %}
+  {% if expvar_url %}
+  expvar.url: {{ expvar_url }}
+  {% endif %}
 ############################# Setup ##########################################
 
 {% if index_name %}

tests/system/test_integration.py

@@ -1,10 +1,8 @@
-from apmserver import ElasticTest, ClientSideBaseTest, SmapCacheBaseTest
-from beat.beat import INTEGRATION_TESTS
 import os
-import json
-import requests
 import unittest
-import time
+
+from apmserver import ElasticTest, ExpvarBaseTest, ClientSideBaseTest, SmapCacheBaseTest
+from beat.beat import INTEGRATION_TESTS
 
 
 class Test(ElasticTest):
@@ -312,3 +310,34 @@ def test_sourcemap_cache_expiration(self):
                                      'error',
                                      1)
         self.check_frontend_error_sourcemap(False, expected_err="No Sourcemap available for")
+
+
+class ExpvarDisabledIntegrationTest(ExpvarBaseTest):
+    config_overrides = {"expvar_enabled": "false"}
+
+    @unittest.skipUnless(INTEGRATION_TESTS, "integration test")
+    def test_expvar_exists(self):
+        """expvar disabled, should 404"""
+        r = self.get_debug_vars()
+        assert r.status_code == 404, r.status_code
+
+
+class ExpvarEnabledIntegrationTest(ExpvarBaseTest):
+    config_overrides = {"expvar_enabled": "true"}
+
+    @unittest.skipUnless(INTEGRATION_TESTS, "integration test")
+    def test_expvar_exists(self):
+        """expvar enabled, should 200"""
+        r = self.get_debug_vars()
+        assert r.status_code == 200, r.status_code
+
+
+class ExpvarCustomUrlIntegrationTest(ExpvarBaseTest):
+    config_overrides = {"expvar_enabled": "true", "expvar_url": "/foo"}
+    expvar_url = ExpvarBaseTest.expvar_url.replace("/debug/vars", "/foo")
+
+    @unittest.skipUnless(INTEGRATION_TESTS, "integration test")
+    def test_expvar_exists(self):
+        """expvar enabled, should 200"""
+        r = self.get_debug_vars()
+        assert r.status_code == 200, r.status_code

tests/system/test_requests.py

@@ -112,6 +112,11 @@ def test_deflate_error(self):
                           headers={'Content-Encoding': 'deflate', 'Content-Type': 'application/json'})
         assert r.status_code == 400, r.status_code
 
+    def test_expvar_default(self):
+        """expvar should not be exposed by default"""
+        r = requests.get(self.expvar_url)
+        assert r.status_code == 404, r.status_code
+
 
 class SecureTest(SecureServerBaseTest):