collectd: Support config of mqtt plugin

mqtt plugin is already built and shipped in
collectd-mod-mqtt, however it is not possible to configure it via
uci currently, instead having to rely on populating the config file manually.

Add support by adding 2 functions, process_mqtt() and
process_mqtt_block(). First one just enables/disables the plugin.
The second one, in the spirit of the curl plugin, adds support for
populating multiple <Publish> and <Subscribe> blocks under <Plugin mqtt>
with support for some parameters. Those are:

* blocktype. Publish or Subscribe. Mandatory
* name. The name of the block. Mandatory
* Host. Mandatory
* Port. Optional
* User. Optional
* Password. Optional
* ClientId. Optional
* QoS. Optional
* Prefix. Optional
* Retain. Optional
* StoreRates. Optional
* CleanSession. Optional
* Topic. Optional

Bump PKG_RELEASE per comments in PR

Signed-off-by: Alexandros Kosiaris <akosiaris@gmail.com>

utils/collectd/Makefile

@@ -9,7 +9,7 @@ include $(TOPDIR)/rules.mk
 
 PKG_NAME:=collectd
 PKG_VERSION:=5.12.0
-PKG_RELEASE:=43
+PKG_RELEASE:=44
 
 PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.bz2
 PKG_SOURCE_URL:=https://collectd.org/files/ \

utils/collectd/files/collectd.init

@@ -124,6 +124,100 @@ process_write_http_node() {
 	printf "\\t</Node>\n" >> "$COLLECTD_CONF"
 }
 
+process_mqtt() {
+	printf "<Plugin mqtt>\n" >> "$COLLECTD_CONF"
+	config_foreach process_mqtt_block mqtt_block
+	printf "</Plugin>\n\n" >> "$COLLECTD_CONF"
+}
+
+process_mqtt_block() {
+	local cfg="$1"
+
+	local blocktype name Host Port User Password ClientId QoS Prefix Retain StoreRates CleanSession Topic
+
+	config_get blocktype "$cfg" blocktype
+	[ -z "$blocktype" ] && {
+		$LOG notice "No blocktype option in config $cfg defined"
+		return 0
+	}
+	config_get name "$cfg" name
+	[ -z "$name" ] && {
+		$LOG notice "No name option in config $cfg defined"
+		return 0
+	}
+	config_get Host "$cfg" Host
+	[ -z "$Host" ] && {
+		$LOG notice "No Host option in config $cfg defined"
+		return 0
+	}
+	config_get Port "$cfg" Port
+	config_get User "$cfg" User
+	config_get Password "$cfg" Password
+	config_get QoS "$cfg" QoS
+	config_get ClientId "$cfg" ClientId
+	config_get Prefix "$cfg" Prefix
+	[ -n "$Prefix" ] && [ "$blocktype" != "Publish" ] && {
+		$LOG notice "Prefix option in config $cfg defined under non Publish block"
+		return 0
+	}
+	config_get Retain "$cfg" Retain
+	[ -n "$Retain" ] && [ "$blocktype" != "Publish" ] && {
+		$LOG notice "Retain option in config $cfg defined under non Publish block"
+		return 0
+	}
+	config_get StoreRates "$cfg" StoreRates
+	[ -n "$StoreRates" ] && [ "$blocktype" != "Publish" ] && {
+		$LOG notice "StoreRates option in config $cfg defined under non Publish block"
+		return 0
+	}
+	config_get CleanSession "$cfg" CleanSession
+	[ -n "$CleanSession" ] && [ "$blocktype" != "Subscribe" ] && {
+		$LOG notice "CleanSession option in config $cfg defined under non Subscribe block"
+		return 0
+	}
+	config_get Topic "$cfg" Topic
+	[ -n "$Topic" ] && [ "$blocktype" != "Subscribe" ] && {
+		$LOG notice "Topic option in config $cfg defined under non Subscribe block"
+		return 0
+	}
+
+	printf "\\t<%s \"%s\">\n" "${blocktype}" "${name}" >> "$COLLECTD_CONF"
+	[ -z "$Host" ] || {
+		printf "\\t\\tHost \"%s\"\n" "${Host}" >> "$COLLECTD_CONF"
+	}
+	[ -z "$Port" ] || {
+		printf "\\t\\tPort \"%s\"\n" "${Port}" >> "$COLLECTD_CONF"
+	}
+	[ -z "$User" ] || {
+		printf "\\t\\tUser \"%s\"\n" "${User}" >> "$COLLECTD_CONF"
+	}
+	[ -z "$Password" ] || {
+		printf "\\t\\tPassword \"%s\"\n" "${Password}" >> "$COLLECTD_CONF"
+	}
+	[ -z "$QoS" ] || {
+		printf "\\t\\tQoS %s\n" "${QoS}" >> "$COLLECTD_CONF"
+	}
+	[ -z "$ClientId" ] || {
+		printf "\\t\\tClientId \"%s\"\n" "${ClientId}" >> "$COLLECTD_CONF"
+	}
+	[ -z "$Prefix" ] || {
+		printf "\\t\\tPrefix \"%s\"\n" "${Prefix}" >> "$COLLECTD_CONF"
+	}
+	[ -z "$Retain" ] || {
+		printf "\\t\\tRetain \"%s\"\n" "${Retain}" >> "$COLLECTD_CONF"
+	}
+	[ -z "$StoreRates" ] || {
+		printf "\\t\\tStoreRates \"%s\"\n" "${StoreRates}" >> "$COLLECTD_CONF"
+	}
+	[ -z "$CleanSession" ] || {
+		printf "\\t\\tCleanSession \"%s\"\n" "${CleanSession}" >> "$COLLECTD_CONF"
+	}
+	[ -z "$Topic" ] || {
+		printf "\\t\\tTopic \"%s\"\n" "${Topic}" >> "$COLLECTD_CONF"
+	}
+	printf "\\t</%s>\n" "${blocktype}" >> "$COLLECTD_CONF"
+}
+
 process_network() {
 	local cfg="$1"
 
@@ -407,6 +501,10 @@ process_plugins() {
 			CONFIG_STRING=""
 			process_write_http
 			;;
+		mqtt)
+			CONFIG_STRING=""
+			process_mqtt
+			;;
 		*)
 			CONFIG_STRING=""
 			process_generic "$cfg" "\\t" "/usr/share/collectd/plugin/$cfg.json"

utils/collectd/files/collectd.uci

@@ -221,3 +221,12 @@ config globals 'globals'
 #config write_http_node
 #	option name 'foo'
 #	option URL 'http://example.org/post-collectd'
+#
+#config plugin 'mqtt'
+#	option enable '1'
+#
+#config mqtt_block
+#	option name 'foo'
+#	option blocktype 'Subscribe'
+#	option Host 'localhost'
+#	option Topic 'collectd/#'

utils/collectd/files/usr/share/collectd/plugin/mqtt.json

@@ -0,0 +1,2 @@
+{
+}