pahoのsandboxとNode-REDでMQTTの練習

初めてWatson IoT Platformを使ってみよう、というかたのためのガイドです。
Watson IoT Platformを使ってみるでIoTアプリを準備しました。
pahoのsandboxとNode-REDを使ってMQTTの基本機能を確認してみます。

0. Node-REDアプリを用意する

• (Watson IoT Platformを使ってみる)[http://qiita.com/egplnt/items/af867711a7191923b2ff]を参照してNode-REDのアプリを２つ（以上）用意します。
• ここではtest01とtest02という２つのNode-REDアプリを用意、とします

1. Node-REDでpublish/subscribeしてみる

• Watson IoT Platform - Node-RED - フローをコピーする方法などを参照し、下記フローをコピペします

Node-REDからpub/sub

[{"id":"11549cdc.190a5b","type":"inject","z":"cd034fba.7dbc28","name":"","topic":"","payload":"こんにちは","payloadType":"str","repeat":"","crontab":"","once":false,"x":160,"y":120,"wires":[["b3080a28.87cde8"]]},{"id":"b3080a28.87cde8","type":"mqtt out","z":"cd034fba.7dbc28","name":"pub01","topic":"/topic1","qos":"","retain":"","broker":"3f1776ff.27a58a","x":310,"y":120,"wires":[]},{"id":"d844b6a.429b2c8","type":"mqtt in","z":"cd034fba.7dbc28","name":"sub01","topic":"/topic1","qos":"0","broker":"5c5b48aa.adc918","x":490,"y":120,"wires":[["75f006d0.d31318"]]},{"id":"75f006d0.d31318","type":"debug","z":"cd034fba.7dbc28","name":"","active":true,"console":"false","complete":"false","x":660,"y":120,"wires":[]},{"id":"e1eed094.12741","type":"comment","z":"cd034fba.7dbc28","name":"とりあえずpub/subしてみる","info":"","x":180,"y":60,"wires":[]},{"id":"6521b93b.134dc","type":"mqtt in","z":"cd034fba.7dbc28","name":"sub02","topic":"/topic1","qos":"0","broker":"35d7209f.7fe68","x":490,"y":180,"wires":[["1bebb39b.6911b4"]]},{"id":"1bebb39b.6911b4","type":"debug","z":"cd034fba.7dbc28","name":"","active":true,"console":"false","complete":"false","x":660,"y":180,"wires":[]},{"id":"d53b122c.36ada8","type":"mqtt in","z":"cd034fba.7dbc28","name":"sub03","topic":"/topic1","qos":"0","broker":"8276a9b0.cc689","x":490,"y":240,"wires":[["6dbe1238.190004"]]},{"id":"6dbe1238.190004","type":"debug","z":"cd034fba.7dbc28","name":"","active":true,"console":"false","complete":"false","x":660,"y":240,"wires":[]},{"id":"3f1776ff.27a58a","type":"mqtt-broker","z":"cd034fba.7dbc28","broker":"iot.eclipse.org","port":"1883","clientid":"pub01","usetls":false,"compatmode":true,"keepalive":"60","cleansession":true,"willTopic":"","willQos":"0","willPayload":"","birthTopic":"","birthQos":"0","birthPayload":""},{"id":"5c5b48aa.adc918","type":"mqtt-broker","z":"cd034fba.7dbc28","broker":"iot.eclipse.org","port":"1883","clientid":"sub01","usetls":false,"compatmode":true,"keepalive":"60","cleansession":true,"willTopic":"","willQos":"0","willPayload":"","birthTopic":"","birthQos":"0","birthPayload":""},{"id":"35d7209f.7fe68","type":"mqtt-broker","z":"","broker":"iot.eclipse.org","port":"1883","clientid":"sub02","usetls":false,"compatmode":true,"keepalive":"60","cleansession":true,"willTopic":"","willQos":"0","willPayload":"","birthTopic":"","birthQos":"0","birthPayload":""},{"id":"8276a9b0.cc689","type":"mqtt-broker","z":"","broker":"iot.eclipse.org","port":"1883","clientid":"sub03","usetls":false,"compatmode":true,"keepalive":"60","cleansession":true,"willTopic":"","willQos":"0","willPayload":"","birthTopic":"","birthQos":"0","birthPayload":""}]

• MQTTブローカーとしてpahoのiot.eclipse.orgを使用しています
• フロー左端の灰色のInjectノードのボタンを押し、メッセージがpublishされ、右側のsubscribeしているフローで受信される事を確認します。一対多の通信が簡単に実現されています。

2. Topicの練習

• 下記のフローをコピペします

Topicの練習

[{"id":"3b2e7d55.5a4342","type":"inject","z":"ae85d786.00355","name":"","topic":"","payload":"こんにちは","payloadType":"str","repeat":"","crontab":"","once":false,"x":140,"y":100,"wires":[["52831a8d.228cd4"]]},{"id":"52831a8d.228cd4","type":"mqtt out","z":"ae85d786.00355","name":"pub11","topic":"/abc/def","qos":"","retain":"","broker":"92f10c84.e84cd8","x":290,"y":100,"wires":[]},{"id":"ec45d90a.78c85","type":"mqtt in","z":"ae85d786.00355","name":"sub11","topic":"/abc","qos":"0","broker":"9e16de64.1b60b","x":460,"y":100,"wires":[["e00ba6d7.c7a2d8"]]},{"id":"e00ba6d7.c7a2d8","type":"debug","z":"ae85d786.00355","name":"/abc を指定","active":true,"console":"false","complete":"payload","x":630,"y":100,"wires":[]},{"id":"6f9f4f23.68ed1","type":"comment","z":"ae85d786.00355","name":"mqtt topicの確認","info":"","x":120,"y":40,"wires":[]},{"id":"43c4573c.2cd25","type":"debug","z":"ae85d786.00355","name":"/abc/def を指定","active":true,"console":"false","complete":"payload","x":640,"y":160,"wires":[]},{"id":"b7f9787f.fbc3b","type":"mqtt in","z":"ae85d786.00355","name":"sub12","topic":"/abc/def","qos":"0","broker":"f429ba39.439e88","x":460,"y":160,"wires":[["43c4573c.2cd25"]]},{"id":"cf23c82f.d4ceb","type":"debug","z":"ae85d786.00355","name":"/abc/# を指定","active":true,"console":"false","complete":"payload","x":640,"y":220,"wires":[]},{"id":"4f860634.ec90b","type":"mqtt in","z":"ae85d786.00355","name":"sub13","topic":"/abc/def","qos":"0","broker":"45f2884d.8ecb48","x":460,"y":220,"wires":[["cf23c82f.d4ceb"]]},{"id":"ad8c2721.3b6c7","type":"debug","z":"ae85d786.00355","name":"/abc/+ を指定","active":true,"console":"false","complete":"payload","x":640,"y":280,"wires":[]},{"id":"d88ed7b8.905e8","type":"mqtt in","z":"ae85d786.00355","name":"sub14","topic":"/abc/+","qos":"0","broker":"b80eef8f.99b28","x":460,"y":280,"wires":[["ad8c2721.3b6c7"]]},{"id":"92f10c84.e84cd8","type":"mqtt-broker","z":"ae85d786.00355","broker":"iot.eclipse.org","port":"1883","clientid":"pub11","usetls":false,"compatmode":true,"keepalive":"60","cleansession":true,"willTopic":"","willQos":"0","willPayload":"","birthTopic":"","birthQos":"0","birthPayload":""},{"id":"9e16de64.1b60b","type":"mqtt-broker","z":"ae85d786.00355","broker":"iot.eclipse.org","port":"1883","clientid":"sub11","usetls":false,"compatmode":true,"keepalive":"60","cleansession":true,"willTopic":"","willQos":"0","willPayload":"","birthTopic":"","birthQos":"0","birthPayload":""},{"id":"f429ba39.439e88","type":"mqtt-broker","z":"ae85d786.00355","broker":"iot.eclipse.org","port":"1883","clientid":"sub12","usetls":false,"compatmode":true,"keepalive":"60","cleansession":true,"willTopic":"","willQos":"0","willPayload":"","birthTopic":"","birthQos":"0","birthPayload":""},{"id":"45f2884d.8ecb48","type":"mqtt-broker","z":"ae85d786.00355","broker":"iot.eclipse.org","port":"1883","clientid":"sub13","usetls":false,"compatmode":true,"keepalive":"60","cleansession":true,"willTopic":"","willQos":"0","willPayload":"","birthTopic":"","birthQos":"0","birthPayload":""},{"id":"b80eef8f.99b28","type":"mqtt-broker","z":"ae85d786.00355","broker":"iot.eclipse.org","port":"1883","clientid":"sub14","usetls":false,"compatmode":true,"keepalive":"60","cleansession":true,"willTopic":"","willQos":"0","willPayload":"","birthTopic":"","birthQos":"0","birthPayload":""}]

• pub11からtopicとして/abc/defへpublishしています
• sub11は/abcへsubscribeしているので受信できていません
• sub12は/abc/defへsubscribeしているので受信できています
• sub13は/abc/#のワイルドカードを使用しているので受信できています。#はマルチレベルのワイルドカードです。参照：IBM IoT MessageSight KnowledgeCenter - ワイルドカード
• sub14は/abc/+のワイルドカードを使用しているので受信できています。+は単一レベルのワイルドカードです。参照：IBM IoT MessageSight KnowledgeCenter - ワイルドカード

3. トピックについてもう少し

• 下記フローをコピペします

もう少しtopicの確認

[{"id":"e5bd7511.7236b8","type":"inject","z":"92d1a08c.d9a43","name":"","topic":"","payload":"こんにちは","payloadType":"str","repeat":"","crontab":"","once":false,"x":140,"y":100,"wires":[["99ed39bb.664c98"]]},{"id":"99ed39bb.664c98","type":"mqtt out","z":"92d1a08c.d9a43","name":"pub21","topic":"/abc/def/ghi","qos":"","retain":"","broker":"1a163edd.4aa579","x":290,"y":100,"wires":[]},{"id":"5ed5b930.0c24c8","type":"mqtt in","z":"92d1a08c.d9a43","name":"sub21","topic":"/abc/+/ghi","qos":"0","broker":"a9f9396e.d91a5","x":460,"y":100,"wires":[["a3ac1a3b.ca2a88"]]},{"id":"a3ac1a3b.ca2a88","type":"debug","z":"92d1a08c.d9a43","name":"/abc/+/ghi を指定","active":true,"console":"false","complete":"payload","x":650,"y":100,"wires":[]},{"id":"de3b795d.5e9c2","type":"comment","z":"92d1a08c.d9a43","name":"もう少しtopicの確認","info":"","x":130,"y":60,"wires":[]},{"id":"d4f876e4.db763","type":"debug","z":"92d1a08c.d9a43","name":"/abc/# を指定","active":true,"console":"false","complete":"payload","x":640,"y":160,"wires":[]},{"id":"4bbca37.283035c","type":"mqtt in","z":"92d1a08c.d9a43","name":"sub22","topic":"/abc/#","qos":"0","broker":"4313f190.64f7b","x":460,"y":160,"wires":[["d4f876e4.db763"]]},{"id":"a11e0a55.4a90e","type":"debug","z":"92d1a08c.d9a43","name":"/abc/def/+ を指定","active":true,"console":"false","complete":"payload","x":650,"y":220,"wires":[]},{"id":"7e968dec.d1b594","type":"mqtt in","z":"92d1a08c.d9a43","name":"sub23","topic":"/abc/def/+","qos":"0","broker":"d0e63210.9ef26","x":460,"y":220,"wires":[["a11e0a55.4a90e"]]},{"id":"b14b1ad8.a7d918","type":"debug","z":"92d1a08c.d9a43","name":"/abc/def/# を指定","active":true,"console":"false","complete":"payload","x":650,"y":280,"wires":[]},{"id":"4adfacc8.314e74","type":"mqtt in","z":"92d1a08c.d9a43","name":"sub24","topic":"/abc/def/#","qos":"0","broker":"4ccafdc1.d76f44","x":460,"y":280,"wires":[["b14b1ad8.a7d918"]]},{"id":"1a163edd.4aa579","type":"mqtt-broker","z":"92d1a08c.d9a43","broker":"iot.eclipse.org","port":"1883","clientid":"pub21","usetls":false,"compatmode":true,"keepalive":"60","cleansession":true,"willTopic":"","willQos":"0","willPayload":"","birthTopic":"","birthQos":"0","birthPayload":""},{"id":"a9f9396e.d91a5","type":"mqtt-broker","z":"92d1a08c.d9a43","broker":"iot.eclipse.org","port":"1883","clientid":"sub21","usetls":false,"compatmode":true,"keepalive":"60","cleansession":true,"willTopic":"","willQos":"0","willPayload":"","birthTopic":"","birthQos":"0","birthPayload":""},{"id":"4313f190.64f7b","type":"mqtt-broker","z":"92d1a08c.d9a43","broker":"iot.eclipse.org","port":"1883","clientid":"sub22","usetls":false,"compatmode":true,"keepalive":"60","cleansession":true,"willTopic":"","willQos":"0","willPayload":"","birthTopic":"","birthQos":"0","birthPayload":""},{"id":"d0e63210.9ef26","type":"mqtt-broker","z":"92d1a08c.d9a43","broker":"iot.eclipse.org","port":"1883","clientid":"sub23","usetls":false,"compatmode":true,"keepalive":"60","cleansession":true,"willTopic":"","willQos":"0","willPayload":"","birthTopic":"","birthQos":"0","birthPayload":""},{"id":"4ccafdc1.d76f44","type":"mqtt-broker","z":"92d1a08c.d9a43","broker":"iot.eclipse.org","port":"1883","clientid":"sub24","usetls":false,"compatmode":true,"keepalive":"60","cleansession":true,"willTopic":"","willQos":"0","willPayload":"","birthTopic":"","birthQos":"0","birthPayload":""}]

- pub21から三層のtopic /abc/def/ghiでpublishしています
- sub21は途中に単一レベルのワイルドカード+を使用し/abc/+/ghiでsubscribeしているので受信できています
- sub22は最後にマルチレベルのワイルドカード#を使用し/abc/#でsubscribeしているので受信できています
- sub23とsub24のワイルドカードの使い方でも受信可能です

4. Retainについて

-一つめのアプリ（test01)で下記フローをコピペします

retainの確認

[{"id":"2fe23a8e.3a2db6","type":"inject","z":"86ec7546.fb684","name":"","topic":"","payload":"こんにちは","payloadType":"str","repeat":"","crontab":"","once":false,"x":140,"y":100,"wires":[["c6d3b4c3.bfdf28"]]},{"id":"c6d3b4c3.bfdf28","type":"mqtt out","z":"86ec7546.fb684","name":"pub31","topic":"/abc","qos":"","retain":"true","broker":"e99c1d45.cc40b8","x":290,"y":100,"wires":[]},{"id":"debfd4bb.8b934","type":"mqtt in","z":"86ec7546.fb684","name":"sub31","topic":"/abc","qos":"0","broker":"ad094ad5.b47958","x":470,"y":100,"wires":[["6dcb18bd.662bb8"]]},{"id":"6dcb18bd.662bb8","type":"debug","z":"86ec7546.fb684","name":"/abc を指定","active":true,"console":"false","complete":"payload","x":630,"y":100,"wires":[]},{"id":"308dd84e.441448","type":"comment","z":"86ec7546.fb684","name":"retainの確認","info":"","x":110,"y":60,"wires":[]},{"id":"e99c1d45.cc40b8","type":"mqtt-broker","z":"86ec7546.fb684","broker":"iot.eclipse.org","port":"1883","clientid":"pub31","usetls":false,"compatmode":true,"keepalive":"60","cleansession":true,"willTopic":"","willQos":"0","willPayload":"","birthTopic":"","birthQos":"0","birthPayload":""},{"id":"ad094ad5.b47958","type":"mqtt-broker","z":"86ec7546.fb684","broker":"iot.eclipse.org","port":"1883","clientid":"sub31","usetls":false,"compatmode":true,"keepalive":"60","cleansession":true,"willTopic":"","willQos":"0","willPayload":"","birthTopic":"","birthQos":"0","birthPayload":""}]

• フロー左端のInjectノードを押し、メッセージが伝搬されるのを確認します。

• 二つめのアプリ（test02)に下記のフローをコピペーします

retainの確認

[{"id":"a23134b8.bf251","type":"debug","z":"fad8a04a.17b828","name":"","active":true,"console":"false","complete":"payload","x":370,"y":100,"wires":[]},{"id":"9cb4cf80.1ff05","type":"mqtt in","z":"fad8a04a.17b828","name":"sub32","topic":"/abc","qos":"2","broker":"89b320f5.3dc71","x":200,"y":100,"wires":[["a23134b8.bf251"]]},{"id":"89b320f5.3dc71","type":"mqtt-broker","z":"fad8a04a.17b828","broker":"iot.eclipse.org","port":"1883","clientid":"sub32","usetls":false,"compatmode":true,"keepalive":"60","cleansession":true,"willTopic":"","willQos":"0","willPayload":"","birthTopic":"","birthQos":"0","birthPayload":""}]

• デプロイしたタイミングで、retainされていたメッセージが伝搬されて受信される事を確認します

• retainされたメッセージを削除するため、以下のフローをコピペします

retainされたメッセージを削除

[{"id":"95ac48b2.aab77","type":"inject","z":"86ec7546.fb684","name":"","topic":"","payload":"","payloadType":"str","repeat":"","crontab":"","once":false,"x":150,"y":420,"wires":[["6e4dc9ce.8a4e7"]]},{"id":"6e4dc9ce.8a4e7","type":"mqtt out","z":"86ec7546.fb684","name":"pub32","topic":"/abc","qos":"","retain":"true","broker":"31ff41ec.c42406","x":320,"y":420,"wires":[]},{"id":"9c845414.379fb","type":"mqtt in","z":"86ec7546.fb684","name":"sub33","topic":"/abc","qos":"0","broker":"b9a16b2a.8dfb78","x":470,"y":420,"wires":[["2352b62d.19ba9a"]]},{"id":"2352b62d.19ba9a","type":"debug","z":"86ec7546.fb684","name":"","active":false,"console":"false","complete":"false","x":630,"y":420,"wires":[]},{"id":"31ff41ec.c42406","type":"mqtt-broker","z":"86ec7546.fb684","broker":"iot.eclipse.org","port":"1883","clientid":"pub32","usetls":false,"compatmode":true,"keepalive":"60","cleansession":true,"willTopic":"","willQos":"0","willPayload":"","birthTopic":"","birthQos":"0","birthPayload":""},{"id":"b9a16b2a.8dfb78","type":"mqtt-broker","z":"86ec7546.fb684","broker":"iot.eclipse.org","port":"1883","clientid":"sub33","usetls":false,"compatmode":true,"keepalive":"60","cleansession":true,"willTopic":"","willQos":"0","willPayload":"","birthTopic":"","birthQos":"0","birthPayload":""}]

• Retainされたものと同じtopicへ長さ０のペイロードのメッセージを送付することでretainされていたメッセージが削除されたことを確認します

5. Birthについて

• 二つめのアプリ(test02)へ以下のフローをコピペします

Birthメッセージを受信するフロー

[{"id":"b33ad244.b9801","type":"debug","z":"9d39d2de.0296c8","name":"/pub41wasborn へsubscribe","active":true,"console":"false","complete":"payload","x":650,"y":100,"wires":[]},{"id":"ac80cb5b.d9051","type":"mqtt in","z":"9d39d2de.0296c8","name":"sub42","topic":"/pub41wasborn","qos":"0","broker":"5e2d77f6.9a1c7","x":430,"y":100,"wires":[["b33ad244.b9801"]]},{"id":"5e2d77f6.9a1c7","type":"mqtt-broker","z":"9d39d2de.0296c8","broker":"iot.eclipse.org","port":"1883","clientid":"sub42","usetls":false,"compatmode":true,"keepalive":"60","cleansession":true,"willTopic":"","willQos":"0","willPayload":"","birthTopic":"","birthQos":"0","birthPayload":""}]

• 一つめのアプリ（test01)へ以下のフローをコピペします

Birthを設定する側のフロー

[{"id":"eae16f1e.161b98","type":"mqtt out","z":"dd86b0dd.f917c","name":"pub41","topic":"/abc","qos":"","retain":"","broker":"4954fbb4.1fde5c","x":790,"y":140,"wires":[]},{"id":"1e8159f0.37251e","type":"comment","z":"dd86b0dd.f917c","name":"birthの確認","info":"","x":680,"y":80,"wires":[]},{"id":"4954fbb4.1fde5c","type":"mqtt-broker","z":"dd86b0dd.f917c","broker":"iot.eclipse.org","port":"1883","clientid":"pub41","usetls":false,"compatmode":true,"keepalive":"60","cleansession":true,"willTopic":"","willQos":"0","willPayload":"","birthTopic":"/pub41wasborn","birthQos":"0","birthPayload":"pub41 was born 2"}]

- このフローではBirthメッセージを設定しています

• 上記のBirthを設定する側のフローをアプリ１にデプロイし接続（MQTT Connection）が確立した時点で、Birthメッセージを受信する側のフロー（test02)でBirthメッセージが受信される事を確認します

6. Willについて

• 二つめのアプリ（test02)に以下のフローをコピペします

Willを受信するフロー

[{"id":"ddb577b3.bbb26","type":"debug","z":"4730cb90.7528fc","name":"/pub51wasdisconnected へsubscribe","active":true,"console":"false","complete":"payload","x":350,"y":120,"wires":[]},{"id":"eadcf57.bace508","type":"mqtt in","z":"4730cb90.7528fc","name":"sub51","topic":"/pub51wasdisconnected","qos":"0","broker":"b1af13e7.66cbf","x":100,"y":120,"wires":[["ddb577b3.bbb26"]]},{"id":"b1af13e7.66cbf","type":"mqtt-broker","z":"4730cb90.7528fc","broker":"iot.eclipse.org","port":"1883","clientid":"sub51","usetls":false,"compatmode":true,"keepalive":"60","cleansession":true,"willTopic":"","willQos":"0","willPayload":"","birthTopic":"","birthQos":"0","birthPayload":""}]

• 一つめのアプリ（test01)に以下のフローをコピペします

Willを伝達する側のフロー

[{"id":"d7d19c0f.1d8de","type":"mqtt out","z":"bd2e6dfa.f03d28","name":"pub51","topic":"/abc","qos":"","retain":"","broker":"ee84b39d.d1375","x":310,"y":140,"wires":[]},{"id":"da81ef5f.38fe5","type":"comment","z":"bd2e6dfa.f03d28","name":"Willの確認","info":"","x":240,"y":80,"wires":[]},{"id":"ee84b39d.d1375","type":"mqtt-broker","z":"bd2e6dfa.f03d28","broker":"iot.eclipse.org","port":"1883","clientid":"pub51","usetls":false,"compatmode":true,"keepalive":"60","cleansession":true,"willTopic":"/pub51wasdisconnected","willQos":"0","willPayload":"pub51 was disconnected","birthTopic":"","birthQos":"0","birthPayload":""}]

• このフローではwillを設定しています。
  

• Bluemixのダッシュボード画面で、一つ目のアプリ（test01)を含むIoTアプリを再起動します

• 再起動したタイミングでMQTTブローカーとの接続が切断され、WILLメッセージが伝搬される事を確認します