add success field to daemon start logging

Summary: records if a start was successful or not

Reviewed By: simpkins

Differential Revision: D19817810

fbshipit-source-id: b67253099781bb534b7e2fb26a09ba41c1f0bd69

eden/fs/service/EdenMain.cpp

@@ -247,6 +247,10 @@ int EdenMain::main(int argc, char** argv) {
 
     prepareFuture = server->prepare(startupLogger, !FLAGS_noWaitForMounts);
   } catch (const std::exception& ex) {
+    auto startTimeInSeconds =
+        std::chrono::duration<double>{daemonStart.elapsed()}.count();
+    server->getServerState()->getStructuredLogger()->logEvent(
+        DaemonStart{startTimeInSeconds, FLAGS_takeover, false /*success*/});
     startupLogger->exitUnsuccessfully(
         EX_SOFTWARE, "error starting edenfs: ", folly::exceptionStr(ex));
   }
@@ -268,10 +272,16 @@ int EdenMain::main(int argc, char** argv) {
       })
       .ensure(
           [daemonStart,
-           structuredLogger = server->getServerState()->getStructuredLogger()] {
+           structuredLogger = server->getServerState()->getStructuredLogger(),
+           takeover = FLAGS_takeover] {
             auto startTimeInSeconds =
                 std::chrono::duration<double>{daemonStart.elapsed()}.count();
-            structuredLogger->logEvent(DaemonStart{startTimeInSeconds});
+            // Here we log a success even if we did not successfully remount
+            // all repositories (if prepareFuture had an exception). In the
+            // future it would be helpful to log number of successful vs
+            // unsuccessful remounts
+            structuredLogger->logEvent(
+                DaemonStart{startTimeInSeconds, takeover, true /*success*/});
           });
 
   runServer(server.value());

eden/fs/service/EdenServer.h

@@ -42,6 +42,7 @@
 #endif
 
 constexpr folly::StringPiece kPeriodicUnloadCounterKey{"PeriodicUnloadCounter"};
+DECLARE_bool(takeover);
 
 namespace cpptoml {
 class table;

eden/fs/telemetry/LogEvent.h

@@ -71,9 +71,13 @@ struct DaemonStart {
   static constexpr const char* type = "daemon_start";
 
   double duration = 0.0;
+  bool is_takeover = false;
+  bool success = false;
 
   void populate(DynamicEvent& event) const {
     event.addDouble("duration", duration);
+    event.addBool("is_takeover", is_takeover);
+    event.addBool("success", success);
   }
 };