Merge pull request #9 from Castaglia/metric-namespacing

Support configuring prefix/suffix labels to the generated metric name…

metric.c

@@ -56,22 +56,26 @@ static int write_metric(struct statsd *statsd, const char *metric_type,
     const char *name, const char *val_prefix, int64_t val, float sampling) {
   int res, xerrno;
   pool *p, *tmp_pool;
+  const char *prefix = NULL, *suffix = NULL;
   char *metric;
   size_t metric_len;
 
+  statsd_statsd_get_namespacing(statsd, &prefix, &suffix);
   p = statsd_statsd_get_pool(statsd);
   tmp_pool = make_sub_pool(p);
 
   metric_len = STATSD_MAX_METRIC_SIZE;
   metric = pcalloc(tmp_pool, metric_len);
 
   if (sampling >= 1.0) {
-    res = snprintf(metric, metric_len-1, "%s:%s%lld|%s",
-      sanitize_name(tmp_pool, name), val_prefix, (long long) val, metric_type);
+    res = snprintf(metric, metric_len-1, "%s%s%s:%s%lld|%s",
+      prefix != NULL ? prefix : "", sanitize_name(tmp_pool, name),
+      suffix != NULL ? suffix : "", val_prefix, (long long) val, metric_type);
 
   } else {
-    res = snprintf(metric, metric_len-1, "%s:%s%lld|%s|@%.2f",
-      sanitize_name(tmp_pool, name), val_prefix, (long long) val, metric_type,
+    res = snprintf(metric, metric_len-1, "%s%s%s:%s%lld|%s|@%.2f",
+      prefix != NULL ? prefix : "", sanitize_name(tmp_pool, name),
+      suffix != NULL ? suffix : "", val_prefix, (long long) val, metric_type,
       sampling);
   }
 

mod_statsd.c

@@ -144,14 +144,18 @@ MODRET set_statsdsampling(cmd_rec *cmd) {
   return PR_HANDLED(cmd);
 }
 
-/* usage: StatsdServer [scheme://]host[:port] */
+/* usage: StatsdServer [scheme://]host[:port] [prefix] [suffix] */
 MODRET set_statsdserver(cmd_rec *cmd) {
   config_rec *c;
   char *server, *ptr;
   size_t server_len;
   int port = STATSD_DEFAULT_PORT, use_tcp = FALSE;
 
-  CHECK_ARGS(cmd, 1);
+  if (cmd->argc < 2 ||
+      cmd->argc > 4) {
+    CONF_ERROR(cmd, "wrong number of parameters");
+  }
+
   CHECK_CONF(cmd, CONF_ROOT|CONF_VIRTUAL|CONF_GLOBAL);
 
   server = pstrdup(cmd->tmp_pool, cmd->argv[1]);
@@ -193,13 +197,37 @@ MODRET set_statsdserver(cmd_rec *cmd) {
     }
   }
 
-  c = add_config_param(cmd->argv[0], 3, NULL, NULL, NULL);
+  c = add_config_param(cmd->argv[0], 5, NULL, NULL, NULL, NULL, NULL);
   c->argv[0] = pstrdup(c->pool, server);
   c->argv[1] = palloc(c->pool, sizeof(int));
   *((int *) c->argv[1]) = port;
   c->argv[2] = pcalloc(c->pool, sizeof(int));
   *((int *) c->argv[2]) = use_tcp;
 
+  if (cmd->argc > 2) {
+    char *prefix;
+
+    prefix = cmd->argv[2];
+    if (*prefix) {
+      /* Automatically append a '.' here, to make construction of the metric
+       * name easier.
+       */
+      c->argv[3] = pstrcat(c->pool, prefix, ".", NULL);
+    }
+  }
+
+  if (cmd->argc == 4) {
+    char *suffix;
+
+    suffix = cmd->argv[3];
+    if (*suffix) {
+      /* Automatically prepend a '.' here, to make construction of the metric
+       * name easier.
+       */
+      c->argv[4] = pstrcat(c->pool, ".", suffix, NULL);
+    }
+  }
+
   return PR_HANDLED(cmd);
 }
 
@@ -300,7 +328,7 @@ static void statsd_shutdown_ev(const void *event_data, void *user_data) {
 
 static int statsd_sess_init(void) {
   config_rec *c;
-  char *host, *metric;
+  char *host, *metric, *prefix = NULL, *suffix = NULL;
   int port, use_tcp = FALSE;
   const pr_netaddr_t *addr;
 
@@ -334,8 +362,11 @@ static int statsd_sess_init(void) {
   pr_netaddr_set_port2((pr_netaddr_t *) addr, port);
 
   use_tcp = *((int *) c->argv[2]);
+  prefix = c->argv[3];
+  suffix = c->argv[4];
 
-  statsd = statsd_statsd_open(session.pool, addr, use_tcp, statsd_sampling);
+  statsd = statsd_statsd_open(session.pool, addr, use_tcp, statsd_sampling,
+    prefix, suffix);
   if (statsd == NULL) {
     pr_log_pri(PR_LOG_NOTICE, MOD_STATSD_VERSION
       ": error opening statsd connection to %s%s:%d: %s",

mod_statsd.html

@@ -81,7 +81,7 @@ <h3><a name="StatsdSampling">StatsdSampling</a></h3>
 
 <hr>
 <h3><a name="StatsdServer">StatsdServer</a></h3>
-<strong>Syntax:</strong> StatsdServer <em>[scheme://]address[:port]</em><br>
+<strong>Syntax:</strong> StatsdServer <em>[scheme://]address[:port] [prefix] [suffix]</em><br>
 <strong>Default:</strong> None<br>
 <strong>Context:</strong> server config, <code>&lt;VirtualHost&gt;</code>, <code>&lt;Global&gt;</code><br>
 <strong>Module:</strong> mod_statsd<br>
@@ -115,6 +115,23 @@ <h3><a name="StatsdServer">StatsdServer</a></h3>
   StatsdServer udp://[::ffff:1.2.3.4]:8125
 </pre>
 
+<p>
+The <code>StatsdServer</code> directive also supports optional <em>prefix</em>
+and <em>suffix</em> values.  These are strings which will be used as prefixes
+and suffixes to the metric names.  For example:
+<pre>
+  StatsdServer udp://1.2.3.4:8125 proftpd.prod ftp03
+</pre>
+This will use the prefix "proftpd.prod", and the suffix "ftp03", to generate
+counter/timer metric names such as <code>proftpd.proftpd.command.PASS.230.ftp03</code>, instead of the default <code>command.PASS.230</code>.  Other examples:
+<pre>
+  # Use a prefix but no suffix for the metrics
+  StatsdServer udp://1.2.3.4:8125 proftpd.prod
+
+  # Use a suffix but no prefix for the metrics
+  StatsdServer udp://1.2.3.4:8125 "" ftp03
+</pre>
+
 <p>
 <hr>
 <h2><a name="Installation">Installation</a></h2>

statsd.c

@@ -36,6 +36,10 @@ struct statsd {
   /* Sampling */
   float sampling;
 
+  /* Namespacing */
+  const char *prefix;
+  const char *suffix;
+
   /* Pending metrics */
   pool *metrics_pool;
   char *metrics_buf;
@@ -48,7 +52,7 @@ static int statsd_proto_udp = IPPROTO_UDP;
 static const char *trace_channel = "statsd.statsd";
 
 struct statsd *statsd_statsd_open(pool *p, const pr_netaddr_t *addr,
-    int use_tcp, float sampling) {
+    int use_tcp, float sampling, const char *prefix, const char *suffix) {
   int family, fd, xerrno;
   pool *sub_pool;
   struct statsd *statsd;
@@ -112,6 +116,14 @@ struct statsd *statsd_statsd_open(pool *p, const pr_netaddr_t *addr,
   statsd->use_tcp = use_tcp;
   statsd->sampling = sampling;
 
+  if (prefix != NULL) {
+    statsd->prefix = pstrdup(statsd->pool, prefix);
+  }
+
+  if (suffix != NULL) {
+    statsd->suffix = pstrdup(statsd->pool, suffix);
+  }
+
   return statsd;
 }
 
@@ -130,6 +142,31 @@ int statsd_statsd_close(struct statsd *statsd) {
   return 0;
 }
 
+int statsd_statsd_get_namespacing(struct statsd *statsd, const char **prefix,
+    const char **suffix) {
+
+  if (statsd == NULL) {
+    errno = EINVAL;
+    return -1;
+  }
+
+  if (prefix == NULL &&
+      suffix == NULL) {
+    errno = EINVAL;
+    return -1;
+  }
+
+  if (prefix != NULL) {
+    *prefix = statsd->prefix;
+  }
+
+  if (suffix != NULL) {
+    *suffix = statsd->suffix;
+  }
+
+  return 0;
+}
+
 pool *statsd_statsd_get_pool(struct statsd *statsd) {
   if (statsd == NULL) {
     errno = EINVAL;

statsd.h

@@ -41,7 +41,7 @@ struct statsd;
 #define STATSD_MAX_METRIC_SIZE			STATSD_MAX_UDP_PACKET_SIZE
 
 struct statsd *statsd_statsd_open(pool *p, const pr_netaddr_t *addr,
-  int use_tcp, float sampling);
+  int use_tcp, float sampling, const char *prefix, const char *suffix);
 int statsd_statsd_close(struct statsd *statsd);
 
 int statsd_statsd_write(struct statsd *statsd, const char *metric,
@@ -51,6 +51,12 @@ int statsd_statsd_write(struct statsd *statsd, const char *metric,
 /* Flush any buffered pending metrics */
 int statsd_statsd_flush(struct statsd *statsd);
 
+/* Returns a reference to the prefix/suffix labels, if any, for this statsd
+ * client.
+ */
+int statsd_statsd_get_namespacing(struct statsd *statsd, const char **prefix,
+  const char **suffix);
+
 /* Returns a reference to pool used for the statsd client. */
 pool *statsd_statsd_get_pool(struct statsd *statsd);
 

t/api/metric.c

@@ -75,7 +75,7 @@ START_TEST (metric_counter_test) {
   addr = statsd_addr(STATSD_DEFAULT_PORT);
 
   mark_point();
-  statsd = statsd_statsd_open(p, addr, FALSE, 1.0);
+  statsd = statsd_statsd_open(p, addr, FALSE, 1.0, NULL, NULL);
   fail_unless(statsd != NULL, "Failed to open statsd connection: %s",
     strerror(errno));
 
@@ -112,7 +112,7 @@ START_TEST (metric_timer_test) {
   addr = statsd_addr(STATSD_DEFAULT_PORT);
 
   mark_point();
-  statsd = statsd_statsd_open(p, addr, FALSE, 1.0);
+  statsd = statsd_statsd_open(p, addr, FALSE, 1.0, NULL, NULL);
   fail_unless(statsd != NULL, "Failed to open statsd connection: %s",
     strerror(errno));
 
@@ -157,7 +157,7 @@ START_TEST (metric_gauge_test) {
   addr = statsd_addr(STATSD_DEFAULT_PORT);
 
   mark_point();
-  statsd = statsd_statsd_open(p, addr, FALSE, 1.0);
+  statsd = statsd_statsd_open(p, addr, FALSE, 1.0, NULL, NULL);
   fail_unless(statsd != NULL, "Failed to open statsd connection: %s",
     strerror(errno));