write_graphite plugin: Adding TCP/UDP support via config

UDP allows to "fire-and-forget" data while not bringing the servers down
due to TCP's connection oriented overhead.

The new versions of Graphite support both TCP and UDP streams so it made
sense to add UDP support.

diff --git a/src/write_graphite.c b/src/write_graphite.c
index 949a842..80f52d3 100644 (file)
--- a/src/write_graphite.c
+++ b/src/write_graphite.c
@@ -35,6 +35,7 @@
   *   <Carbon>
   *     Host "localhost"
   *     Port "2003"
+  *     Protocol "udp"
   *     Prefix "collectd"
   *   </Carbon>
   * </Plugin>
@@ -64,6 +65,10 @@
 # define WG_DEFAULT_SERVICE "2003"
 #endif
 
+#ifndef WG_DEFAULT_PROTOCOL
+# define WG_DEFAULT_PROTOCOL "udp"
+#endif
+
 #ifndef WG_DEFAULT_ESCAPE
 # define WG_DEFAULT_ESCAPE '_'
 #endif
@@ -84,6 +89,7 @@ struct wg_callback
 
     char    *node;
     char    *service;
+    char    *protocol;
     char    *prefix;
     char    *postfix;
     char     escape_char;
@@ -119,7 +125,8 @@ static int wg_send_buffer (struct wg_callback *cb)
     if (status < 0)
     {
         char errbuf[1024];
-        ERROR ("write_graphite plugin: send failed with status %zi (%s)",
+        ERROR ("write_graphite plugin: send to %s:%s (%s) failed with status %zi (%s)",
+                cb->node, cb->service, cb->protocol,
                 status, sstrerror (errno, errbuf, sizeof (errbuf)));
 
 
@@ -173,6 +180,7 @@ static int wg_callback_init (struct wg_callback *cb)
 
     const char *node = cb->node ? cb->node : WG_DEFAULT_NODE;
     const char *service = cb->service ? cb->service : WG_DEFAULT_SERVICE;
+    const char *protocol = cb->protocol ? cb->protocol : WG_DEFAULT_PROTOCOL;
 
     if (cb->sock_fd > 0)
         return (0);
@@ -182,15 +190,25 @@ static int wg_callback_init (struct wg_callback *cb)
     ai_hints.ai_flags |= AI_ADDRCONFIG;
 #endif
     ai_hints.ai_family = AF_UNSPEC;
-    ai_hints.ai_socktype = SOCK_STREAM;
+
+    if (0 == strcasecmp ("tcp", protocol))
+        ai_hints.ai_socktype = SOCK_STREAM;
+    else if (0 == strcasecmp ("udp", protocol))
+        ai_hints.ai_socktype = SOCK_DGRAM;
+    else
+    {
+        ERROR ("write_graphite plugin: unknown protocol (%s)",
+                protocol);
+        return (-1);
+    }
 
     ai_list = NULL;
 
     status = getaddrinfo (node, service, &ai_hints, &ai_list);
     if (status != 0)
     {
-        ERROR ("write_graphite plugin: getaddrinfo (%s, %s) failed: %s",
-                node, service, gai_strerror (status));
+        ERROR ("write_graphite plugin: getaddrinfo (%s, %s, %s) failed: %s",
+                node, service, protocol, gai_strerror (status));
         return (-1);
     }
 
@@ -219,8 +237,8 @@ static int wg_callback_init (struct wg_callback *cb)
     {
         char errbuf[1024];
         c_complain (LOG_ERR, &cb->init_complaint,
-                "write_graphite plugin: Connecting to %s:%s failed. "
-                "The last error was: %s", node, service,
+                "write_graphite plugin: Connecting to %s:%s via %s failed. "
+                "The last error was: %s", node, service, protocol,
                 sstrerror (errno, errbuf, sizeof (errbuf)));
         close (cb->sock_fd);
         return (-1);
@@ -228,8 +246,8 @@ static int wg_callback_init (struct wg_callback *cb)
     else
     {
         c_release (LOG_INFO, &cb->init_complaint,
-                "write_graphite plugin: Successfully connected to %s:%s.",
-                node, service);
+                "write_graphite plugin: Successfully connected to %s:%s via %s.",
+                node, service, protocol);
     }
 
     wg_reset_buffer (cb);
@@ -255,6 +273,7 @@ static void wg_callback_free (void *data)
 
     sfree(cb->name);
     sfree(cb->node);
+    sfree(cb->protocol);
     sfree(cb->service);
     sfree(cb->prefix);
     sfree(cb->postfix);
@@ -335,9 +354,10 @@ static int wg_send_message (char const *message, struct wg_callback *cb)
     cb->send_buf_fill += message_len;
     cb->send_buf_free -= message_len;
 
-    DEBUG ("write_graphite plugin: [%s]:%s buf %zu/%zu (%.1f %%) \"%s\"",
+    DEBUG ("write_graphite plugin: [%s]:%s (%s) buf %zu/%zu (%.1f %%) \"%s\"",
             cb->node,
             cb->service,
+            cb->protocol,
             cb->send_buf_fill, sizeof (cb->send_buf),
             100.0 * ((double) cb->send_buf_fill) / ((double) sizeof (cb->send_buf)),
             message);
@@ -442,6 +462,7 @@ static int wg_config_node (oconfig_item_t *ci)
     cb->name = NULL;
     cb->node = NULL;
     cb->service = NULL;
+    cb->protocol = NULL;
     cb->prefix = NULL;
     cb->postfix = NULL;
     cb->escape_char = WG_DEFAULT_ESCAPE;
@@ -469,6 +490,8 @@ static int wg_config_node (oconfig_item_t *ci)
             cf_util_get_string (child, &cb->node);
         else if (strcasecmp ("Port", child->key) == 0)
             cf_util_get_service (child, &cb->service);
+        else if (strcasecmp ("Protocol", child->key) == 0)
+            cf_util_get_string (child, &cb->protocol);
         else if (strcasecmp ("Prefix", child->key) == 0)
             cf_util_get_string (child, &cb->prefix);
         else if (strcasecmp ("Postfix", child->key) == 0)
@@ -493,9 +516,10 @@ static int wg_config_node (oconfig_item_t *ci)
 
     /* FIXME: Legacy configuration syntax. */
     if (cb->name == NULL)
-        ssnprintf (callback_name, sizeof (callback_name), "write_graphite/%s/%s",
+        ssnprintf (callback_name, sizeof (callback_name), "write_graphite/%s/%s/%s",
                 cb->node != NULL ? cb->node : WG_DEFAULT_NODE,
-                cb->service != NULL ? cb->service : WG_DEFAULT_SERVICE);
+                cb->service != NULL ? cb->service : WG_DEFAULT_SERVICE,
+                cb->protocol != NULL ? cb->protocol : WG_DEFAULT_PROTOCOL);
     else
         ssnprintf (callback_name, sizeof (callback_name), "write_graphite/%s",
                 cb->name);