From a2f4c30a03dad7979c494aaf638cf2330fa39e72 Mon Sep 17 00:00:00 2001
From: Florian Forster <octo@collectd.org>
Date: Mon, 3 Jun 2013 09:07:15 +0200
Subject: [PATCH] write_riemann plugin: Implement the "TTLFactor" option.

Github: #336
---
 src/collectd.conf.pod | 11 ++++++++++-
 src/write_riemann.c   | 35 ++++++++++++++++++++++++++++++++++-
 2 files changed, 44 insertions(+), 2 deletions(-)

diff --git a/src/collectd.conf.pod b/src/collectd.conf.pod
index b66c4350..541af4ce 100644
--- a/src/collectd.conf.pod
+++ b/src/collectd.conf.pod
@@ -6034,7 +6034,7 @@ Synopsis:
      Protocol UDP
      StoreRates true
      AlwaysAppendDS false
-     Delay 10
+     TTLFactor 2.0
    </Node>
    Tag "foobar"
  </Plugin>
@@ -6081,6 +6081,15 @@ If set the B<true>, append the name of the I<Data Source> (DS) to the
 identifies a metric in I<Riemann>. If set to B<false> (the default), this is
 only done when there is more than one DS.
 
+=item B<TTLFactor> I<Factor>
+
+I<Riemann> events have a I<Time to Live> (TTL) which specifies how long each
+event is considered active. I<collectd> populates this field based on the
+metrics interval setting. This setting controls the factor with which the
+interval is multiplied to set the TTL. The default value is B<2.0>. Unless you
+know exactly what you're doing, you should only increase this setting from its
+default value.
+
 =back
 
 =item B<Tag> I<String>
diff --git a/src/write_riemann.c b/src/write_riemann.c
index d31a988e..3e2ddd75 100644
--- a/src/write_riemann.c
+++ b/src/write_riemann.c
@@ -37,6 +37,7 @@
 
 #define RIEMANN_HOST		"localhost"
 #define RIEMANN_PORT		"5555"
+#define RIEMANN_TTL_FACTOR      2.0
 
 struct riemann_host {
 	char			*name;
@@ -49,6 +50,7 @@ struct riemann_host {
 	char			*service;
 	_Bool			 use_tcp;
 	int			 s;
+	double			 ttl_factor;
 
 	int			 reference_count;
 };
@@ -365,6 +367,7 @@ static Event *riemann_value_to_protobuf (struct riemann_host const *host, /* {{{
 	Event *event;
 	char name_buffer[5 * DATA_MAX_NAME_LEN];
 	char service_buffer[6 * DATA_MAX_NAME_LEN];
+	double ttl;
 	int i;
 
 	event = malloc (sizeof (*event));
@@ -379,7 +382,9 @@ static Event *riemann_value_to_protobuf (struct riemann_host const *host, /* {{{
 	event->host = strdup (vl->host);
 	event->time = CDTIME_T_TO_TIME_T (vl->time);
 	event->has_time = 1;
-	event->ttl = CDTIME_T_TO_TIME_T (2 * vl->interval);
+
+	ttl = CDTIME_T_TO_DOUBLE (vl->interval) * host->ttl_factor;
+	event->ttl = (float) ttl;
 	event->has_ttl = 1;
 
 	riemann_event_add_attribute (event, "plugin", vl->plugin);
@@ -597,6 +602,7 @@ riemann_config_node(oconfig_item_t *ci)
 	host->store_rates = 1;
 	host->always_append_ds = 0;
 	host->use_tcp = 0;
+	host->ttl_factor = RIEMANN_TTL_FACTOR;
 
 	status = cf_util_get_string (ci, &host->name);
 	if (status != 0) {
@@ -656,6 +662,33 @@ riemann_config_node(oconfig_item_t *ci)
 					&host->always_append_ds);
 			if (status != 0)
 				break;
+		} else if (strcasecmp ("TTLFactor", child->key) == 0) {
+			double tmp = NAN;
+			status = cf_util_get_double (child, &tmp);
+			if (status != 0)
+				break;
+			if (tmp >= 2.0) {
+				host->ttl_factor = tmp;
+			} else if (tmp >= 1.0) {
+				NOTICE ("write_riemann plugin: The configured "
+						"TTLFactor is very small "
+						"(%.1f). A value of 2.0 or "
+						"greater is recommended.",
+						tmp);
+				host->ttl_factor = tmp;
+			} else if (tmp > 0.0) {
+				WARNING ("write_riemann plugin: The configured "
+						"TTLFactor is too small to be "
+						"useful (%.1f). I'll use it "
+						"since the user knows best, "
+						"but under protest.",
+						tmp);
+				host->ttl_factor = tmp;
+			} else { /* zero, negative and NAN */
+				ERROR ("write_riemann plugin: The configured "
+						"TTLFactor is invalid (%.1f).",
+						tmp);
+			}
 		} else {
 			WARNING("write_riemann plugin: ignoring unknown config "
 				"option: \"%s\"", child->key);
-- 
2.30.2