Added Prometheus metrics

wsvpn.c

@@ -83,7 +83,13 @@ struct metrics {
   uint64_t received_bytes;
   uint64_t received_messages;
   uint64_t errors;
-} metrics;
+
+  uint64_t method_calls[5];
+} metrics = { 0 };
+
+const char method_names[5][8] = {
+  "open", "isOpen", "close", "closeAll", "transmit"
+};
 
 int main(void) {
   const char *address = "ws://0.0.0.0:8667";
@@ -104,25 +110,38 @@ static void handle_client(struct mg_connection *connection, int event_type, void
     struct mg_http_message *http_message = (struct mg_http_message *) event_data;
     if (mg_http_match_uri(http_message, "/open")) {
       mg_ws_upgrade(connection, http_message, NULL);
-    } else if (mg_http_match_uri(http_message, "/stat")) {
+    } else if (mg_http_match_uri(http_message, "/metrics")) {
       mg_printf(connection, "HTTP/1.1 200 OK\r\nTransfer-Encoding: chunked\r\n\r\n");
-      static char addr_str[256];
+      mg_http_printf_chunk(connection, "# HELP ws_bytes_sent_total Number of bytes sent to clients\n");
+      mg_http_printf_chunk(connection, "# TYPE ws_bytes_sent_total counter\n");
+      mg_http_printf_chunk(connection, "ws_bytes_sent_total %ld\n", metrics.sent_bytes);
+      mg_http_printf_chunk(connection, "# HELP ws_bytes_received_total Number of bytes received to clients\n");
+      mg_http_printf_chunk(connection, "# TYPE ws_bytes_received_total counter\n");
+      mg_http_printf_chunk(connection, "ws_bytes_received_total %ld\n", metrics.received_bytes);
+
+      mg_http_printf_chunk(connection, "# HELP ws_messages_sent_total Number of messages sent to clients\n");
+      mg_http_printf_chunk(connection, "# TYPE ws_messages_sent_total counter\n");
+      mg_http_printf_chunk(connection, "ws_messages_sent_total %ld\n", metrics.sent_messages);
+      mg_http_printf_chunk(connection, "# HELP ws_messages_received_total Number of messages received to clients\n");
+      mg_http_printf_chunk(connection, "# TYPE ws_messages_received_total counter\n");
+      mg_http_printf_chunk(connection, "ws_messages_received_total %ld\n", metrics.received_messages);
+
+      mg_http_printf_chunk(connection, "# HELP ws_clients Number of active websocket clients\n");
+      mg_http_printf_chunk(connection, "# TYPE ws_clients gauge\n");
+      {
+        int n = 0;
         for (struct mg_connection *conn = connection->mgr->conns; conn != NULL; conn = conn->next) {
-        if (conn->is_websocket) {
+          if (conn->is_websocket) { n++; }
-          struct client *client = *(struct client **)&conn->data[0];
-          if (client->connection == conn) {
-            mg_snprintf(addr_str, 256, "%M", mg_print_ip_port, &conn->rem);
-            mg_http_printf_chunk(connection, "%s - %d ports {", addr_str, client->next_open_channel_index);
-            for (int i = 0; i < MAX_OPEN_CHANNELS; i++) {
-              if (i == client->next_open_channel_index) {
-                mg_http_printf_chunk(connection, "/*end of used*/");
-              }
-              mg_http_printf_chunk(connection, "%d,", client->open_channels[i]);
-            }
-            mg_http_printf_chunk(connection, "}\n");
         }
+        mg_http_printf_chunk(connection, "ws_clients %d\n", n);
       }
+
+      mg_http_printf_chunk(connection, "# HELP method_calls Times each method was called\n");
+      mg_http_printf_chunk(connection, "# TYPE method_calls counter\n");
+      for (int i = 0; i < 5; i++) {
+        mg_http_printf_chunk(connection, "method_calls{method=\"%s\"} %ld\n", method_names[i], metrics.method_calls[i]);
       }
+
       mg_http_printf_chunk(connection, "");
     } else {
       mg_http_reply(connection, 404, "", "uwu");
@@ -160,6 +179,8 @@ void ws_send_error(struct mg_connection *connection, uint16_t request_id, const
   buffer[4] = text_size & 0xFF;
 
   metrics.sent_bytes += 5 + text_size;
+  metrics.sent_messages++;
+  metrics.errors++;
   mg_ws_send(connection, buffer, 5 + text_size, WEBSOCKET_OP_BINARY);
 }
 
@@ -178,6 +199,7 @@ void ws_send_info(struct mg_connection *connection, const char *fmt, ...) {
   buffer[2] = text_size & 0xFF;
 
   metrics.sent_bytes += 3 + text_size;
+  metrics.sent_messages++;
   mg_ws_send(connection, buffer, 3 + text_size, WEBSOCKET_OP_BINARY);
 }
 
@@ -189,6 +211,7 @@ void ws_respond(struct mg_connection *connection, uint16_t request_id, void *dat
   buffer[2] = request_id & 0xFF;
   if (size != 0) memcpy(&buffer[3], data, size);
   metrics.sent_bytes += 3 + size;
+  metrics.sent_messages++;
   mg_ws_send(connection, buffer, size + 3, WEBSOCKET_OP_BINARY);
 }
 
@@ -200,6 +223,8 @@ static void on_ws_connect(struct mg_connection *connection, struct mg_http_messa
   static char buffer[256];
   buffer[0] = 'A';
   buffer[1] = snprintf(&buffer[2], 250, "wsvpn_%ld", connection->id);
+  metrics.sent_bytes += 2 + buffer[1];
+  metrics.sent_messages++;
   mg_ws_send(connection, buffer, 2 + buffer[1], WEBSOCKET_OP_BINARY);
 }
 
@@ -214,6 +239,7 @@ static void on_ws_message(struct mg_connection *connection, struct mg_ws_message
   assert(client->connection == connection);
 
   metrics.received_bytes += message->data.len;
+  metrics.received_messages++;
 
   if (message->data.len == 0) return;
 
@@ -224,6 +250,7 @@ static void on_ws_message(struct mg_connection *connection, struct mg_ws_message
       break;
     case 'O': // open
       {
+        metrics.method_calls[0]++;
         uint16_t channel = ntohs(*(uint16_t*)&message->data.ptr[3]);
         printf("%p[%04x] modem.open(%d)\n", client, request_id, channel);
         modem_open(client, request_id, channel);
@@ -231,6 +258,7 @@ static void on_ws_message(struct mg_connection *connection, struct mg_ws_message
       return;
     case 'o': // isOpen
       {
+        metrics.method_calls[1]++;
         uint16_t channel = ntohs(*(uint16_t*)&message->data.ptr[3]);
         printf("%p[%04x] modem.isOpen(%d)\n", client, request_id, channel);
         modem_isOpen(client, request_id, channel);
@@ -238,6 +266,7 @@ static void on_ws_message(struct mg_connection *connection, struct mg_ws_message
       return;
     case 'c': // close
       {
+        metrics.method_calls[2]++;
         uint16_t channel = ntohs(*(uint16_t*)&message->data.ptr[3]);
         printf("%p[%04x] modem.close(%d)\n", client, request_id, channel);
         modem_close(client, request_id, channel);
@@ -245,12 +274,14 @@ static void on_ws_message(struct mg_connection *connection, struct mg_ws_message
       return;
     case 'C': // closeAll
       {
+        metrics.method_calls[3]++;
         printf("%p[%04x] modem.closeAll()\n", client, request_id);
         modem_closeAll(client, request_id);
       }
       return;
     case 'T': // transmit
       {
+        metrics.method_calls[4]++;
         uint16_t channel = ntohs(*(uint16_t*)&message->data.ptr[3]);
         uint16_t reply_channel = ntohs(*(uint16_t*)&message->data.ptr[5]);
         uint16_t data_length = ntohs(*(uint16_t*)&message->data.ptr[7]);
@@ -273,16 +304,15 @@ static void on_ws_disconnect(struct mg_connection *connection, void *data) {
 
 
 static void modem_open(struct client *client, uint16_t request_id, uint16_t channel) {
-  for (int i = 0; i < client->next_open_channel_index; i++) {
+  if (client_is_open(client, channel)) {
-    if (client->open_channels[i] == channel) {
     ws_respond(client->connection, request_id, NULL, 0);
-      return;
-    }
   }
+
   if (client->next_open_channel_index == MAX_OPEN_CHANNELS) {
     ws_send_error(client->connection, request_id, "Too many open channels");
     return;
   }
+
   client->open_channels[client->next_open_channel_index] = channel;
   client->next_open_channel_index++;
   ws_respond(client->connection, request_id, NULL, 0);
@@ -332,6 +362,8 @@ static void modem_transmit(struct client *client, uint16_t request_id, uint16_t
       struct client *other_client = *(struct client **)&conn->data[0];
       if (other_client->connection == conn && other_client->connection != client->connection) {
         if (client_is_open(other_client, channel)) {
+          metrics.sent_bytes += size + 7;
+          metrics.sent_messages++;
           mg_ws_send(other_client->connection, buffer, size + 7, WEBSOCKET_OP_BINARY);
         }
       }