lib-master, master: Initialize stats-client via environment variables

That way it's initialized before settings are read, and it can catch events
earlier. It also doesn't require all services to read settings if they
otherwise don't need them.

src/lib-master/master-interface.h

@@ -79,6 +79,10 @@ enum master_login_state {
    be used to initialize debug logging immediately at startup. */
 #define DOVECOT_LOG_DEBUG_ENV "LOG_DEBUG"
 
+/* getenv(DOVECOT_STATS_WRITER_SOCKET_PATH) returns path to the stats-writer
+   socket. */
+#define DOVECOT_STATS_WRITER_SOCKET_PATH "STATS_WRITER_SOCKET_PATH"
+
 /* Write pipe to anvil. */
 #define MASTER_ANVIL_FD 3
 /* Anvil reads new log fds from this fd */

src/lib-master/master-service-settings.c

@@ -768,13 +768,13 @@ int master_service_settings_read(struct master_service *service,
 		/* running standalone. we want to ignore plugin versions. */
 		service->version_string = NULL;
 	}
-	if ((service->flags & MASTER_SERVICE_FLAG_SEND_STATS) != 0) {
+	if ((service->flags & MASTER_SERVICE_FLAG_SEND_STATS) != 0 &&
+	    (service->flags & MASTER_SERVICE_FLAG_STANDALONE) != 0) {
 		/* When running standalone (e.g. doveadm) try to connect to the
 		   stats socket, but don't log an error if it's not running.
-		   It may be intentional. */
-		bool silent_notfound_errors =
-			(service->flags & MASTER_SERVICE_FLAG_STANDALONE) != 0;
-		master_service_init_stats_client(service, silent_notfound_errors);
+		   It may be intentional. Non-standalone stats-client
+		   initialization was already done earlier. */
+		master_service_init_stats_client(service, TRUE);
 	}
 
 	if (service->set->shutdown_clients)

src/lib-master/master-service.c

@@ -338,6 +338,12 @@ master_service_init(const char *name, enum master_service_flags flags,
 		   are dropped. */
 		master_service_config_socket_try_open(service);
 	}
+	if ((flags & MASTER_SERVICE_FLAG_SEND_STATS) != 0) {
+		/* Initialize stats-client early so it can see all events. */
+		value = getenv(DOVECOT_STATS_WRITER_SOCKET_PATH);
+		if (value != NULL)
+			service->stats_client = stats_client_init(value, FALSE);
+	}
 
 	master_service_verify_version_string(service);
 	return service;

src/master/service-process.c

@@ -232,6 +232,8 @@ static void
 service_process_setup_environment(struct service *service, unsigned int uid,
 				  const char *hostdomain)
 {
+	const struct master_service_settings *service_set =
+		service->list->service_set;
 	master_service_env_clean();
 
 	env_put(MASTER_IS_PARENT_ENV"=1");
@@ -255,6 +257,11 @@ service_process_setup_environment(struct service *service, unsigned int uid,
 	if (!service->set->master_set->version_ignore)
 		env_put(MASTER_DOVECOT_VERSION_ENV"="PACKAGE_VERSION);
 
+	if (service_set->stats_writer_socket_path[0] != '\0') {
+		env_put(t_strdup_printf(DOVECOT_STATS_WRITER_SOCKET_PATH"=%s/%s",
+					service_set->base_dir,
+					service_set->stats_writer_socket_path));
+	}
 	if (ssl_manual_key_password != NULL && service->have_inet_listeners) {
 		/* manually given SSL password. give it only to services
 		   that have inet listeners. */
@@ -265,7 +272,7 @@ service_process_setup_environment(struct service *service, unsigned int uid,
 	    service_anvil_global->restarted)
 		env_put("ANVIL_RESTARTED=1");
 	env_put(t_strconcat(DOVECOT_LOG_DEBUG_ENV"=",
-			    service->list->service_set->log_debug, NULL));
+			    service_set->log_debug, NULL));
 }
 
 static void service_process_status_timeout(struct service_process *process)