Initial commit

Signed-off-by: André Srinivasan <andre.srinivasan@gmail.com>

.gitignore

@@ -0,0 +1,3 @@
+.venv
+mqtt-hello-world.yaml
+exercise.yaml

.vscode/launch.json

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+{
+    // Use IntelliSense to learn about possible attributes.
+    // Hover to view descriptions of existing attributes.
+    // For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
+    "version": "0.2.0",
+    "configurations": [
+        {
+            "name": "Python Debugger: Current File",
+            "type": "debugpy",
+            "request": "launch",
+            "program": "${file}",
+            "console": "integratedTerminal",
+            "justMyCode": false,
+        }
+    ]
+}

README.md

@@ -1 +1,2 @@
-# cumulocity-first-device-agent
+# Cumulocity First Device Agent
+

exercise.py

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+#!/usr/bin/env python3
+
+import random
+import time
+import paho.mqtt.client as mqtt
+import yaml
+
+with open("exercise.yaml", "r") as f:
+    config = yaml.safe_load(f)
+
+serverUrl = config["serverUrl"]
+clientId = config["clientId"]
+device_name = config["device_name"]
+tenant = config["tenant"]
+username = config["username"]
+password = config["password"]
+
+
+def on_publish(client, userdata, mid, reason_code, properties):
+    print(f"Published message: {mid}")
+
+
+def publish():
+    temperature = random.randint(10, 20)
+    mqttc.publish("s/us", f"211,{temperature}")
+    return
+
+
+def on_message(client, userdata, message):
+    payload = message.payload.decode("utf-8")
+
+    c8yType = ""
+    if payload.startswith("511"):
+        print(f"Received shell command: {payload}")
+        c8yType = "c8y_Command"
+    elif payload.startswith("513"):
+        print(f"Received config change: {payload}")
+        c8yType = "c8y_Configuration"
+    else:
+        print(f"Received unrecognized payload: {payload}")
+        exit(1)
+
+    client.publish("s/us", f"501,{c8yType}", qos=1).wait_for_publish(1)
+    client.publish("s/us", f"503,{c8yType},Success")
+
+
+mqttc = mqtt.Client(mqtt.CallbackAPIVersion.VERSION2, clientId)
+mqttc.username_pw_set(tenant + "/" + username, password)
+mqttc.on_publish = on_publish
+mqttc.on_message = on_message
+
+mqttc.connect(serverUrl)
+mqttc.loop_start()
+
+mqttc.publish("s/us", f"100,{device_name},c8y_MQTTDevice", qos=1).wait_for_publish(1)
+print("Device registered.")
+
+mqttc.publish("s/us", "114,c8y_Command,c8y_Configuration")
+print("Command and configuration enabled.")
+
+mqttc.subscribe("s/ds")
+print("Subscribed.")
+
+try:
+    while True:
+        publish()
+        time.sleep(1)
+except (KeyboardInterrupt, SystemExit):
+    pass
+
+mqttc.disconnect()
+mqttc.loop_stop()
+
+exit(0)

mqtt-hello-world.py

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+#!/usr/bin/env python3
+
+## From https://cumulocity.com/guides/device-integration/mqtt-examples/#hello-mqtt-python
+
+import paho.mqtt.client as mqtt
+import time, random, threading
+import multiprocessing as mp
+import yaml
+
+with open("mqtt-hello-world.yaml", "r") as f:
+    config = yaml.safe_load(f)
+
+# client, user and device details
+serverUrl = config["serverUrl"]
+clientId = config["clientId"]
+device_name = config["device_name"]
+tenant = config["tenant"]
+username = config["username"]
+password = config["password"]
+
+# task queue to overcome issue with paho when using multiple threads:
+#   https://github.com/eclipse/paho.mqtt.python/issues/354
+task_queue = mp.Queue()
+
+
+# display all incoming messages
+def on_message(client, userdata, message):
+    payload = message.payload.decode("utf-8")
+    print(" < received message " + payload)
+    if payload.startswith("510"):
+        task_queue.put(perform_restart)
+
+
+# simulate restart
+def perform_restart():
+    print("Simulating device restart...")
+    publish("s/us", "501,c8y_Restart", wait_for_ack=True)
+
+    print("...restarting...")
+    time.sleep(1)
+
+    publish("s/us", "503,c8y_Restart", wait_for_ack=True)
+    print("...restart completed")
+
+
+# send temperature measurement
+def send_measurement():
+    print("Sending temperature measurement...")
+    temperature = random.randint(10, 20)
+    publish("s/us", "211,{}".format(temperature))
+
+
+# publish a message
+def publish(topic, message, wait_for_ack=False):
+    QoS = 2 if wait_for_ack else 0
+    message_info = client.publish(topic, message, QoS)
+    if wait_for_ack:
+        print(" > awaiting ACK for {}".format(message_info.mid))
+        message_info.wait_for_publish()
+        print(" < received ACK for {}".format(message_info.mid))
+
+
+# display all outgoing messages
+def on_publish(client, userdata, mid, reason_code, properties):
+    print(" > published message: {}".format(mid))
+
+
+# main device loop
+def device_loop():
+    while True:
+        task_queue.put(send_measurement)
+        time.sleep(7)
+
+
+# connect the client to Cumulocity IoT and register a device
+client = mqtt.Client(mqtt.CallbackAPIVersion.VERSION2, clientId)
+client.username_pw_set(tenant + "/" + username, password)
+client.on_message = on_message
+client.on_publish = on_publish
+
+client.connect(serverUrl)
+client.loop_start()
+
+client.publish("s/us", "100," + device_name + ",c8y_MQTTDevice")
+print("Device created")
+
+client.subscribe("s/ds")
+
+device_loop_thread = threading.Thread(target=device_loop)
+device_loop_thread.daemon = True
+device_loop_thread.start()
+
+# process all tasks on queue
+try:
+    while True:
+        task = task_queue.get()
+        task()
+except (KeyboardInterrupt, SystemExit):
+    print("Received keyboard interrupt, quitting ...")
+    exit(0)