arangodb · KVS85 · Aug 27, 2021 · Aug 26, 2021 · Aug 26, 2021
diff --git a/CHANGELOG b/CHANGELOG
@@ -1,6 +1,10 @@
 v3.7.15 (XXXX-XX-XX)
 --------------------
 
+* Make statistics available in metrics API even if `--server.statistics` is set
+  to `false`. This allows clients to fetch some process statistics metrics from
+  instances that have statistics aggregation and storage turned off.
+
 * Updated arangosync to 1.8.0.
 
 * Added protocol specific metrics: histogram about request body size, total

diff --git a/arangod/RestServer/MetricsFeature.cpp b/arangod/RestServer/MetricsFeature.cpp
@@ -85,9 +85,7 @@ void MetricsFeature::validateOptions(std::shared_ptr<ProgramOptions>) {
   }
 }
 
-
 void MetricsFeature::toPrometheus(std::string& result) const {
-
   // minimize reallocs
   result.reserve(32768);
 
@@ -100,10 +98,8 @@ void MetricsFeature::toPrometheus(std::string& result) const {
 
   // StatisticsFeature
   auto& sf = server().getFeature<StatisticsFeature>();
-  if (sf.enabled()) {
-    sf.toPrometheus(result, std::chrono::duration<double, std::milli>(
-                      std::chrono::system_clock::now().time_since_epoch()).count());
-  }
+  sf.toPrometheus(result, std::chrono::duration<double, std::milli>(
+                    std::chrono::system_clock::now().time_since_epoch()).count());
 
   // RocksDBEngine
   auto es = EngineSelectorFeature::ENGINE;

diff --git a/arangod/Statistics/ConnectionStatistics.cpp b/arangod/Statistics/ConnectionStatistics.cpp
@@ -72,11 +72,6 @@ ConnectionStatistics::Item ConnectionStatistics::acquire() {
 }
 
 void ConnectionStatistics::getSnapshot(Snapshot& snapshot) {
-  if (!StatisticsFeature::enabled()) {
-    // all the below objects may be deleted if we don't have statistics enabled
-    return;
-  }
-
   snapshot.httpConnections = statistics::HttpConnections;
   snapshot.totalRequests = statistics::TotalRequests;
   snapshot.totalRequestsSuperuser = statistics::TotalRequestsSuperuser;

diff --git a/arangod/Statistics/RequestStatistics.cpp b/arangod/Statistics/RequestStatistics.cpp
@@ -195,11 +195,6 @@ void RequestStatistics::release() {
 }
 
 void RequestStatistics::getSnapshot(Snapshot& snapshot, stats::RequestStatisticsSource source) {
-  if (!StatisticsFeature::enabled()) {
-    // all the below objects may be deleted if we don't have statistics enabled
-    return;
-  }
-
   statistics::RequestFigures& figures = source == stats::RequestStatisticsSource::USER
     ? statistics::UserRequestFigures
     : statistics::SuperuserRequestFigures;

diff --git a/arangod/Statistics/StatisticsFeature.cpp b/arangod/Statistics/StatisticsFeature.cpp
diff --git a/arangod/Statistics/StatisticsFeature.h b/arangod/Statistics/StatisticsFeature.h
@@ -24,6 +24,7 @@
 #define APPLICATION_FEATURES_STATISTICS_FEATURE_H 1
 
 #include <array>
+#include <initializer_list>
 
 #include "ApplicationFeatures/ApplicationFeature.h"
 #include "Basics/Result.h"
@@ -115,7 +116,15 @@ class StatisticsFeature final : public application_features::ApplicationFeature
 
   bool allDatabases() const { return _statisticsAllDatabases; }
 
+  static arangodb::velocypack::Builder fillDistribution(statistics::Distribution const& dist);
+
  private:
+  void appendHistogram(
+    std::string& result, statistics::Distribution const& dist,
+    std::string const& label, std::initializer_list<std::string> const& les) const;
+  void appendMetric(
+    std::string& result, std::string const& val, std::string const& label) const;
+
   bool _statistics;
   bool _statisticsHistory;
   bool _statisticsHistoryTouched;

diff --git a/arangod/Statistics/StatisticsWorker.cpp b/arangod/Statistics/StatisticsWorker.cpp
diff --git a/arangod/Statistics/StatisticsWorker.h b/arangod/Statistics/StatisticsWorker.h
@@ -73,12 +73,6 @@ class StatisticsWorker final : public Thread {
   // save one statistics object
   void saveSlice(velocypack::Slice const&, std::string const&) const;
 
-  void appendHistogram(
-    std::string& result, statistics::Distribution const& dist,
-    std::string const& label, std::initializer_list<std::string> const& les) const;
-  void appendMetric(
-    std::string& result, std::string const& val, std::string const& label) const;
-
   static constexpr uint64_t STATISTICS_INTERVAL = 10;    // 10 secs
   static constexpr uint64_t GC_INTERVAL = 8 * 60;        //  8 mins
   static constexpr uint64_t HISTORY_INTERVAL = 15 * 60;  // 15 mins

diff --git a/tests/js/client/server_parameters/test-statistics-enabled-false.js b/tests/js/client/server_parameters/test-statistics-enabled-false.js
@@ -0,0 +1,88 @@
+/*jshint globalstrict:false, strict:false */
+/* global getOptions, assertEqual, assertTrue, arango */
+
+////////////////////////////////////////////////////////////////////////////////
+/// @brief test for security-related server options
+///
+/// @file
+///
+/// DISCLAIMER
+///
+/// Copyright 2010-2012 triagens 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 Inc, Cologne, Germany
+///
+/// @author Jan Steemann
+/// @author Copyright 2019, ArangoDB Inc, Cologne, Germany
+////////////////////////////////////////////////////////////////////////////////
+
+if (getOptions === true) {
+  return {
+    'server.statistics': "false",
+    'server.export-metrics-api': "true",
+  };
+}
+
+const jsunity = require('jsunity');
+
+function testSuite() {
+  return {
+    testGetAdminStatistics : function() {
+      let res = arango.GET("/_admin/statistics");
+      assertTrue(res.error);
+      assertEqual(404, res.code);
+    },
+
+    testGetAdminStatisticsDescription : function() {
+      let res = arango.GET("/_admin/statistics-description");
+      assertTrue(res.error);
+      assertEqual(404, res.code);
+    },
+
+    testGetMetrics : function() {
+      let metrics = {};
+      String(arango.GET("/_admin/metrics"))
+        .split("\n")
+        .filter((line) => line.match(/^[^#]/))
+        .filter((line) => line.match(/^arangodb_/))
+        .forEach((line) => {
+          let name = line.replace(/[ \{].*$/g, '');
+          let value = Number(line.replace(/^.+ (\d+)$/, '$1'));
+          metrics[name] = value;
+        });
+
+      const expected = [
+        "arangodb_process_statistics_minor_page_faults",
+        "arangodb_process_statistics_major_page_faults",
+        "arangodb_process_statistics_user_time",
+        "arangodb_process_statistics_system_time",
+        "arangodb_process_statistics_number_of_threads",
+        "arangodb_process_statistics_resident_set_size",
+        "arangodb_process_statistics_resident_set_size_percent",
+        "arangodb_process_statistics_virtual_memory_size",
+        "arangodb_server_statistics_physical_memory",
+        "arangodb_server_statistics_server_uptime",
+      ];
+
+      expected.forEach((name) => {
+        assertTrue(metrics.hasOwnProperty(name));
+        assertEqual("number", typeof metrics[name]);
+      });
+    },
+  };
+}
+
+jsunity.run(testSuite);
+return jsunity.done();