cassandra: Track query counts internally and include them in metrics

src/lib-sql/driver-cassandra.c

@@ -29,6 +29,29 @@
 
 typedef void driver_cassandra_callback_t(CassFuture *future, void *context);
 
+enum cassandra_counter_type {
+	CASSANDRA_COUNTER_TYPE_QUERY_SENT,
+	CASSANDRA_COUNTER_TYPE_QUERY_RECV_OK,
+	CASSANDRA_COUNTER_TYPE_QUERY_RECV_ERR_NO_HOSTS,
+	CASSANDRA_COUNTER_TYPE_QUERY_RECV_ERR_QUEUE_FULL,
+	CASSANDRA_COUNTER_TYPE_QUERY_RECV_ERR_CLIENT_TIMEOUT,
+	CASSANDRA_COUNTER_TYPE_QUERY_RECV_ERR_SERVER_TIMEOUT,
+	CASSANDRA_COUNTER_TYPE_QUERY_RECV_ERR_SERVER_UNAVAILABLE,
+	CASSANDRA_COUNTER_TYPE_QUERY_RECV_ERR_OTHER,
+
+	CASSANDRA_COUNTER_COUNT
+};
+static const char *counter_names[CASSANDRA_COUNTER_COUNT] = {
+	"sent",
+	"recv_ok",
+	"recv_err_no_hosts",
+	"recv_err_queue_full",
+	"recv_err_client_timeout",
+	"recv_err_server_timeout",
+	"recv_err_server_unavailable",
+	"recv_err_other",
+};
+
 enum cassandra_query_type {
 	CASSANDRA_QUERY_TYPE_READ,
 	CASSANDRA_QUERY_TYPE_WRITE,
@@ -76,6 +99,7 @@ struct cassandra_db {
 
 	char *metrics_path;
 	struct timeout *to_metrics;
+	uint64_t counters[CASSANDRA_COUNTER_COUNT];
 
 	struct timeval first_fallback_sent[CASSANDRA_QUERY_TYPE_COUNT];
 	time_t last_fallback_warning[CASSANDRA_QUERY_TYPE_COUNT];
@@ -515,17 +539,26 @@ driver_cassandra_get_metrics_json(struct cassandra_db *db, string_t *dest)
 	ADD_DOUBLE(requests, five_minute_rate);
 	ADD_DOUBLE(requests, fifteen_minute_rate);
 	str_truncate(dest, str_len(dest)-1);
+
 	str_append(dest, "}, \"stats\": {");
 	ADD_UINT64(stats, total_connections);
 	ADD_UINT64(stats, available_connections);
 	ADD_UINT64(stats, exceeded_pending_requests_water_mark);
 	ADD_UINT64(stats, exceeded_write_bytes_water_mark);
 	str_truncate(dest, str_len(dest)-1);
+
 	str_append(dest, "}, \"errors\": {");
 	ADD_UINT64(errors, connection_timeouts);
 	ADD_UINT64(errors, pending_request_timeouts);
 	ADD_UINT64(errors, request_timeouts);
 	str_truncate(dest, str_len(dest)-1);
+
+	str_append(dest, "}, \"queries\": {");
+	for (unsigned int i = 0; i < CASSANDRA_COUNTER_COUNT; i++) {
+		str_printfa(dest, "\"%s\": %llu,", counter_names[i],
+			    (unsigned long long)db->counters[i]);
+	}
+	str_truncate(dest, str_len(dest)-1);
 	str_append(dest, "}}");
 }
 
@@ -732,6 +765,30 @@ static void query_resend_with_fallback(struct cassandra_result *result)
 	driver_cassandra_result_send_query(result);
 }
 
+static void counters_inc_error(struct cassandra_db *db, CassError error)
+{
+	switch (error) {
+	case CASS_ERROR_LIB_NO_HOSTS_AVAILABLE:
+		db->counters[CASSANDRA_COUNTER_TYPE_QUERY_RECV_ERR_NO_HOSTS]++;
+		break;
+	case CASS_ERROR_LIB_REQUEST_QUEUE_FULL:
+		db->counters[CASSANDRA_COUNTER_TYPE_QUERY_RECV_ERR_QUEUE_FULL]++;
+		break;
+	case CASS_ERROR_LIB_REQUEST_TIMED_OUT:
+		db->counters[CASSANDRA_COUNTER_TYPE_QUERY_RECV_ERR_CLIENT_TIMEOUT]++;
+		break;
+	case CASS_ERROR_SERVER_WRITE_TIMEOUT:
+		db->counters[CASSANDRA_COUNTER_TYPE_QUERY_RECV_ERR_SERVER_TIMEOUT]++;
+		break;
+	case CASS_ERROR_SERVER_UNAVAILABLE:
+		db->counters[CASSANDRA_COUNTER_TYPE_QUERY_RECV_ERR_SERVER_UNAVAILABLE]++;
+		break;
+	default:
+		db->counters[CASSANDRA_COUNTER_TYPE_QUERY_RECV_ERR_OTHER]++;
+		break;
+	}
+}
+
 static void query_callback(CassFuture *future, void *context)
 {
 	struct cassandra_result *result = context;
@@ -747,12 +804,14 @@ static void query_callback(CassFuture *future, void *context)
 		i_free(result->error);
 
 		msecs = timeval_diff_msecs(&ioloop_timeval, &result->start_time);
+		counters_inc_error(db, error);
 		result->api.error_type = error == CASS_ERROR_SERVER_WRITE_TIMEOUT ||
 			error == CASS_ERROR_LIB_REQUEST_TIMED_OUT ?
 			SQL_RESULT_ERROR_TYPE_WRITE_UNCERTAIN :
 			SQL_RESULT_ERROR_TYPE_UNKNOWN;
 		result->error = i_strdup_printf("Query '%s' failed: %.*s (in %u.%03u secs)",
 			result->query, (int)errsize, errmsg, msecs/1000, msecs%1000);
+
 		/* unavailable = cassandra server knows that there aren't
 		   enough nodes available.
 
@@ -771,6 +830,7 @@ static void query_callback(CassFuture *future, void *context)
 		result_finish(result);
 		return;
 	}
+	db->counters[CASSANDRA_COUNTER_TYPE_QUERY_RECV_OK]++;
 
 	if (result->fallback_consistency != result->consistency) {
 		/* non-fallback query finished successfully. if there had been
@@ -788,6 +848,8 @@ static void driver_cassandra_result_send_query(struct cassandra_result *result)
 	struct cassandra_db *db = (struct cassandra_db *)result->api.db;
 	CassFuture *future;
 
+	db->counters[CASSANDRA_COUNTER_TYPE_QUERY_SENT]++;
+
 	result->statement = cass_statement_new(result->query, 0);
 	cass_statement_set_consistency(result->statement, result->consistency);