Folks --
Update 2018-04-19: It's working! I'll leave the post as-was and append the solution at the end
Here's a post summarizing some Golang code on an Omega2 connecting to Google Cloud IoT Core.
I'm a Googler and an Onion (!?) and have 3x Omega2s.
On Sunday I noticed this post on the Onion Developer docs showing integration with cloud platforms and was encouraged to add Google Cloud Platform to this list. In the post, I describe working Golang code that connects Omegas to Google Cloud IoT Core.
I'm struggling to get connectivity with Mosquitto as outlined in the Onion document but I know how to get connectivity working (because the Golang code works). When I try mosquitto_pub commands below, I don't promptly receive the messages on GCP (as I do with the Golang code).
I'd value your help. I've redacted values and replaced with $VARIABLES but the values are correctly reflected in the config. Cloud IoT MQTT uses a JWT for the password and there's no mutual auth. I pulled the JWT code from the Golang and use this to generate the value for $JWT used in the config below so I'm confident that's correct too.
I suspect one error is in the mapping of topics:
# For debugging
log_type all
log_dest file /var/log/mosquitto/mosquitto.log
connection_messages true
tls_version tlsv1.2
# Bridge to GCP Cloud IoT Core
connection bridge-to-gcp
address mqtt.googleapis.com:8883
cleansession true
bridge_attempt_unsubscribe false
bridge_cafile /roots.pem
remote_username unused
remote_password $JWT
remote_clientid projects/$PROJECT/locations/$REGION/registries/$REGISTRY/devices/$DEVICE
topic # out 1
topic # in 1
For the clientid shown above, at least 2 MQTT topics are available, telemetry can go out on /devices/$DEVICE/event and config arrives on /devices/$DEVICE/config
I tried:
mosquitto_pub \
--topic /events \
--message '{"test": "Hello Henry!"}' \
--qos 1
mosquitto_pub \
--topic /devices/$DEVICE/events \
--message '{"test": "Hello Henry!"}' \
--qos 1
mosquitto_pub \
--topic projects/$PROJECT/locations/$REGION/registries/$REGISTRY/devices/$DEVICE/events \
--message '{"test": "Hello Henry!"}' \
--qos 1
Here's part of the logs when trying to mosquitto_pub:
New connection from 127.0.0.1 on port 1883.
New client connected from 127.0.0.1 as mosqpub/3501-20237b7dc0 (c1, k60).
Sending CONNACK to mosqpub/3501-20237b7dc0 (0, 0)
Received PUBLISH from mosqpub/3501-20237b7dc0 (d0, q1, r0, m1, '/events', ... (24 bytes))
Sending PUBACK to mosqpub/3501-20237b7dc0 (Mid: 1)
Received DISCONNECT from mosqpub/3501-20237b7dc0
Client mosqpub/3501-20237b7dc0 disconnected.
New connection from 127.0.0.1 on port 1883.
New client connected from 127.0.0.1 as mosqpub/3502-20237b7dc0 (c1, k60).
Sending CONNACK to mosqpub/3502-20237b7dc0 (0, 0)
Received PUBLISH from mosqpub/3502-20237b7dc0 (d0, q1, r0, m1, '/devices/$DEVICE/events', ... (24 bytes))
Sending PUBACK to mosqpub/3502-20237b7dc0 (Mid: 1)
Received DISCONNECT from mosqpub/3502-20237b7dc0
Client mosqpub/3502-20237b7dc0 disconnected.
New connection from 127.0.0.1 on port 1883.
New client connected from 127.0.0.1 as mosqpub/3503-20237b7dc0 (c1, k60).
Sending CONNACK to mosqpub/3503-20237b7dc0 (0, 0)
Received PUBLISH from mosqpub/3503-20237b7dc0 (d0, q1, r0, m1, 'projects/$PROJECT/locations/$REGION/registries/$REGISTRY/devices/$DEVICE/events', ... (24 bytes))
Sending PUBACK to mosqpub/3503-20237b7dc0 (Mid: 1)
Received DISCONNECT from mosqpub/3503-20237b7dc0
Client mosqpub/3503-20237b7dc0 disconnected.
Bridge local.projects/$PROJECT/locations/$REGION/registries/$REGISTRY/devices/$DEVICE doing local SUBSCRIBE on topic #
I found some guidance on the always-excellent Digital Ocean site and am able to send messages to Cloud IoT using mosquitto_pub:
mosquitto_pub \
--host mqtt.googleapis.com \
--port 8883 \
--id ${LONG_REGISTRY}/devices/${DEVICE} \
--username unused \
--pw ${PASSWORD} \
--cafile /roots.pem \
--tls-version tlsv1.2 \
--protocol-version mqttv311 \
--debug \
--topic /devices/${DEVICE}/events \
--message "$(date +"%y%m%d%H%M%S") Hello Henry!"
So the problem (I think) is in my configuration file.
Update: working
I had some help from a colleague who helped me understand that my attempt to use an MQTT broker was my problem and that Google Cloud IoT Core does not work with sub-brokers. Instead, I was advised to focus on the mosquitto_pub and mosquitto_sub approach which, as you saw previously, does work. So, that's the solution.
mosquitto_pub \
--host mqtt.googleapis.com \
--port 8883 \
--id ${LONG_REGISTRY}/devices/${DEVICE} \
--username unused \
--pw ${PASSWORD} \
--cafile /roots.pem \
--tls-version tlsv1.2 \
--protocol-version mqttv311 \
--debug \
--qos 1\
--topic /devices/${DEVICE}/events \
--message "$(date +"%y%m%d%H%M%S") Hello Henry!"
and this:
mosquitto_sub \
--host mqtt.googleapis.com \
--port 8883 \
--id ${LONG_REGISTRY}/devices/${DEVICE} \
--username unused \
--pw ${PASSWORD} \
--cafile /roots.pem \
--tls-version tlsv1.2 \
--protocol-version mqttv311 \
--debug \
--qos 1 \
--topic /devices/${DEVICE}/config
