tree e109b3c3ea12a66de36a43a8c3fb9f5193a3bb0c
parent 7e1ef6ce913b0904b61490f380c546a573897644
author Luca Milanesio <luca.milanesio@gmail.com> 1724881018 +0100
committer Luca Milanesio <luca.milanesio@gmail.com> 1724885346 +0000

Add missing Singleton to ActiveWokersCheck and DeadlockCheck

The ActiveWorkersCheck was triggering the creation
of a new check for every incoming REST-API call, causing
potential deadlocks because of the creation of the
DropWizard's MetricMaker.

As a consequence, the Gerrit instance could have ran
out of incoming HTTP threads.

See as example stack trace:

HTTP GET /config/server/healthcheck~status
   java.lang.Thread.State: BLOCKED (on object monitor)
	at com.google.gerrit.metrics.dropwizard.DropWizardMetricMaker.newCounter(DropWizardMetricMaker.java:142)
	- waiting to lock <0x00007f828e8b80b0> (a com.google.gerrit.metrics.dropwizard.DropWizardMetricMaker)
	at com.google.gerrit.server.plugins.PluginMetricMaker.newCounter(PluginMetricMaker.java:55)
	at com.googlesource.gerrit.plugins.healthcheck.HealthCheckMetrics.getFailureCounterMetric(HealthCheckMetrics.java:33)
	at com.googlesource.gerrit.plugins.healthcheck.check.AbstractHealthCheck.<init>(AbstractHealthCheck.java:54)
	at com.googlesource.gerrit.plugins.healthcheck.check.ActiveWorkersCheck.<init>(ActiveWorkersCheck.java:46)

Change-Id: I947b46b58e1d44840b3a44f740627e55dc3194aa
(cherry picked from commit 1c93439e98cc4efb3a44880278a9cbbe5628d36b)