Merge branch 'stable-3.1'

* stable-3.1:
  Move addition of refs/users/self symlink out of filtering logic
  Separate account tests that assert push behavior into own class
  Update recommended version of buildifier to 2.0.0
  Proc metrics: add average system load for the last minute
  Proc metrics: add available number of cores
  Add more metrics about Java threads

Change-Id: I2403648c358bf21f5ed3ffbb3429d8b483641e81

Documentation/dev-crafting-changes.txt

@@ -116,7 +116,7 @@ To format Java source code, Gerrit uses the
 link:https://github.com/google/google-java-format[`google-java-format`,role=external,window=_blank]
 tool (version 1.7), and to format Bazel BUILD, WORKSPACE and .bzl files the
 link:https://github.com/bazelbuild/buildtools/tree/master/buildifier[`buildifier`,role=external,window=_blank]
-tool (version 1.0.0). Unused dependencies are found and removed using the
+tool (version 2.0.0). Unused dependencies are found and removed using the
 link:https://github.com/bazelbuild/buildtools/tree/master/unused_deps[`unused_deps`,role=external,window=_blank]
 build tool, a sibling of `buildifier`.
 

Documentation/metrics.txt

@@ -37,7 +37,9 @@ split up by update type (create+replace, autoclose, normal)
 
 * `proc/birth_timestamp`: Time at which the Gerrit process started.
 * `proc/uptime`: Uptime of the Gerrit process.
+* `proc/cpu/num_cores`: Number of processors available to the Java virtual machine.
 * `proc/cpu/usage`: CPU time used by the Gerrit process.
+* `proc/cpu/system_load`: System load average for the last minute.
 * `proc/num_open_fds`: Number of open file descriptors.
 * `proc/jvm/memory/heap_committed`: Amount of memory guaranteed for user objects.
 * `proc/jvm/memory/heap_used`: Amount of memory holding user objects.
@@ -49,6 +51,9 @@ objects needing finalization.
 * `proc/jvm/gc/count`: Number of GCs.
 * `proc/jvm/gc/time`: Approximate accumulated GC elapsed time.
 * `proc/jvm/thread/num_live`: Current live thread count.
+* `proc/jvm/thread/num_daemon_live`: Current live daemon threads count.
+* `proc/jvm/thread/num_peak_live`: Peak live thread count since the Java virtual machine started or peak was reset.
+* `proc/jvm/thread/num_total_started`: Total number of threads created and also started since the Java virtual machine started.
 
 === Caches
 

java/com/google/gerrit/metrics/proc/ProcMetricModule.java

@@ -28,6 +28,7 @@ import java.lang.management.GarbageCollectorMXBean;
 import java.lang.management.ManagementFactory;
 import java.lang.management.MemoryMXBean;
 import java.lang.management.MemoryUsage;
+import java.lang.management.OperatingSystemMXBean;
 import java.lang.management.ThreadMXBean;
 import java.util.concurrent.TimeUnit;
 
@@ -37,6 +38,7 @@ public class ProcMetricModule extends MetricModule {
     buildLabel(metrics);
     procUptime(metrics);
     procCpuUsage(metrics);
+    procCpuLoad(metrics);
     procJvmGc(metrics);
     procJvmMemory(metrics);
     procJvmThread(metrics);
@@ -84,6 +86,23 @@ public class ProcMetricModule extends MetricModule {
           new Description("Number of open file descriptors").setGauge().setUnit("fds"),
           provider::getOpenFileDescriptorCount);
     }
+    metrics.newCallbackMetric(
+        "proc/cpu/num_cores",
+        Integer.class,
+        new Description("Number of processors available to the Java virtual machine").setGauge(),
+        Runtime.getRuntime()::availableProcessors);
+  }
+
+  private void procCpuLoad(MetricMaker metrics) {
+    OperatingSystemMXBean provider =
+        ManagementFactory.getPlatformMXBean(OperatingSystemMXBean.class);
+    if (provider.getSystemLoadAverage() != -1) {
+      metrics.newCallbackMetric(
+          "proc/cpu/system_load",
+          Double.class,
+          new Description("System load average for the last minute").setGauge(),
+          provider::getSystemLoadAverage);
+    }
   }
 
   private void procJvmMemory(MetricMaker metrics) {
@@ -194,5 +213,26 @@ public class ProcMetricModule extends MetricModule {
         Integer.class,
         new Description("Current live thread count").setGauge().setUnit("threads"),
         thread::getThreadCount);
+    metrics.newCallbackMetric(
+        "proc/jvm/thread/num_daemon_live",
+        Integer.class,
+        new Description("Current live daemon threads count").setGauge().setUnit("threads"),
+        thread::getDaemonThreadCount);
+    metrics.newCallbackMetric(
+        "proc/jvm/thread/num_peak_live",
+        Integer.class,
+        new Description(
+                "Peak live thread count since the Java virtual machine started or peak was reset")
+            .setGauge()
+            .setUnit("threads"),
+        thread::getPeakThreadCount);
+    metrics.newCallbackMetric(
+        "proc/jvm/thread/num_total_started",
+        Long.class,
+        new Description(
+                "Total number of threads created and also started since the Java virtual machine started")
+            .setGauge()
+            .setUnit("threads"),
+        thread::getTotalStartedThreadCount);
   }
 }