From c630212dde2d741912bdf09fe9b7f22e97e8194d Mon Sep 17 00:00:00 2001
From: Pieter Slabbert <zan.xhipe@gmail.com>
Date: Thu, 24 Nov 2016 17:11:24 +0200
Subject: [PATCH] Enable setting a clientID for MQTT Output

closes #2079
closes #1910
---
 CHANGELOG.md                 |  1 +
 plugins/outputs/mqtt/mqtt.go | 12 ++++++++++--
 2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index c745d462f3dfb..d5c08c3b2f15a 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -24,6 +24,7 @@ in their config file.
 - [#1937](https://github.com/influxdata/telegraf/pull/1937): HAProxy session limit metric.
 - [#2068](https://github.com/influxdata/telegraf/issues/2068): Accept strings for StatsD sets.
 - [#1893](https://github.com/influxdata/telegraf/issues/1893): Change StatsD default "reset" behavior.
+- [#2079](https://github.com/influxdata/telegraf/pull/2079): Enable setting ClientID in MQTT output.
 
 ### Bugfixes
 
diff --git a/plugins/outputs/mqtt/mqtt.go b/plugins/outputs/mqtt/mqtt.go
index 45f2c91c8bc54..b1d94f87ccf32 100644
--- a/plugins/outputs/mqtt/mqtt.go
+++ b/plugins/outputs/mqtt/mqtt.go
@@ -25,6 +25,9 @@ var sampleConfig = `
   # username = "telegraf"
   # password = "metricsmetricsmetricsmetrics"
 
+  ## client ID, if not set a random ID is generated
+  # client_id = ""
+
   ## Optional SSL Config
   # ssl_ca = "/etc/telegraf/ca.pem"
   # ssl_cert = "/etc/telegraf/cert.pem"
@@ -46,7 +49,8 @@ type MQTT struct {
 	Database    string
 	Timeout     internal.Duration
 	TopicPrefix string
-	QoS         int `toml:"qos"`
+	QoS         int    `toml:"qos"`
+	ClientID    string `toml:"client_id"`
 
 	// Path to CA file
 	SSLCA string `toml:"ssl_ca"`
@@ -155,7 +159,11 @@ func (m *MQTT) publish(topic string, body []byte) error {
 func (m *MQTT) createOpts() (*paho.ClientOptions, error) {
 	opts := paho.NewClientOptions()
 
-	opts.SetClientID("Telegraf-Output-" + internal.RandomString(5))
+	if m.ClientID != "" {
+		opts.SetClientID(m.ClientID)
+	} else {
+		opts.SetClientID("Telegraf-Output-" + internal.RandomString(5))
+	}
 
 	tlsCfg, err := internal.GetTLSConfig(
 		m.SSLCert, m.SSLKey, m.SSLCA, m.InsecureSkipVerify)