log client name

Summary:
As we consider potential future options for Watchman, it's helpful to know
who the watchman clients are. And how many requests they are sending us.

Adds the command name of the client process so we can keep track of who is
calling us.

Planning to decrease retention on this column to 1 week, so we don't run out
of capacity.

Reviewed By: MichaelCuevas

Differential Revision: D61480221

fbshipit-source-id: 4b4aa3e44de5b0dbbfe49e753113ab3a92a7e465

watchman/Client.cpp

@@ -183,6 +183,11 @@ bool Client::dispatchCommand(const Command& command, CommandFlags mode) {
  eventCount != samplingRate ? 0 : eventCount;
  dispatchCommand.args = renderedString;
  dispatchCommand.client_pid = peerPid_;
+ auto processName = peerInfo_.get().name;
+ std::replace(processName.begin(), processName.end(), '\0', ' ');
+ auto cleanName = folly::rtrimWhitespace(processName);
+ dispatchCommand.client_name = cleanName;
+
  getLogger()->logEvent(dispatchCommand);
  }
 

watchman/telemetry/LogEvent.h

@@ -86,6 +86,7 @@ struct DispatchCommand {
  std::string command;
  std::string args;
  pid_t client_pid = 0;
+ std::string client_name;
 
  void populate(DynamicEvent& event) const {
  meta.populate(event);
@@ -96,6 +97,9 @@ struct DispatchCommand {
  if (client_pid != 0) {
  event.addInt("client_pid", client_pid);
  }
+ if (!client_name.empty()) {
+ event.addString("client", client_name);
+ }
  }
 };