hunting down invalid mutex in shutdown of agency

arangod/Agency/AgencyFeature.cpp

@@ -44,7 +44,7 @@ AgencyFeature::AgencyFeature(application_features::ApplicationServer* server)
       _notify(false),
       _supervision(false),
       _waitForSync(true),
-      _supervisionFrequency(5.0),
+      _supervisionFrequency(1.0),
       _compactionStepSize(1000) {
   setOptional(true);
   requiresElevatedPrivileges(false);

arangod/Agency/Agent.cpp

@@ -381,13 +381,15 @@ void Agent::beginShutdown() {
   // Personal hygiene
   Thread::beginShutdown();
 
+  // Stop supervision
+  if (_config.supervision) {
+    _supervision.beginShutdown();
+  }
+
   // Stop constituent and key value stores
   _constituent.beginShutdown();
   _spearhead.beginShutdown();
   _readDB.beginShutdown();
-  if (_config.supervision) {
-    _supervision.beginShutdown();
-  }
 
   // Wake up all waiting REST handler (waitFor)
   CONDITION_LOCKER(guard, _appendCV);

arangod/Agency/Supervision.cpp

@@ -124,7 +124,9 @@ std::vector<check_t> Supervision::checkDBServers() {
     report->close();
     report->close();
     report->close();
-    _agent->write(report);
+    if (!this->isStopping()) {
+      _agent->write(report);
+    }
       
   }
 
@@ -235,7 +237,7 @@ bool Supervision::start(Agent* agent) {
 bool Supervision::updateAgencyPrefix (size_t nTries, int intervalSec) {
 
   // Try nTries to get agency's prefix in intervals 
-  for (size_t i = 0; i < nTries; i++) {
+  while (!this->isStopping()) {
     _snapshot = _agent->readDB().get("/");
     if (_snapshot.children().size() > 0) {
       _agencyPrefix = std::string("/") + _snapshot.children().begin()->first;
@@ -256,7 +258,7 @@ void Supervision::getUniqueIds() {
   uint64_t latestId;
   // Run forever, supervision does not make sense before the agency data
   // is initialized by some other server...
-  while (true) {
+  while (!this->isStopping()) {
     try {
       latestId = std::stoul(
           _agent->readDB().get(_agencyPrefix + "/Sync/LatestID").slice().toJson());