paho-mqtt: add package and example

[javierfileiv]

Contribution description

This PR adds PAHO-MQTT package and example running on native

Testing procedure

Application in examples/mqtt-paho builds for native board. Follow README in folder.

[pokgak]

Hi, is there a reason why you created the header file in RIOT? I have no experience using the library but based on a quick look on existing ports here I think this should be done there instead under directory named RIOT/ and the name for some functions should be changed to riot_read(), riot_write() instead of mqtt_read() and mqtt_write().

Generally, if you need to write glue code for the library, the *.c files can go to a pkg/<pkg name>/contrib/ directory and the header files can go to pkg/<pkg name>/includes/ directory. See this for example.

[javierfileiv]

Hi, is there a reason why you created the header file in RIOT? I have no experience using the library but based on a quick look on existing ports here I think this should be done there instead under directory named RIOT/ and the name for some functions should be changed to riot_read(), riot_write() instead of mqtt_read() and mqtt_write().

Generally, if you need to write glue code for the library, the *.c files can go to a pkg/<pkg name>/contrib/ directory and the header files can go to pkg/<pkg name>/includes/ directory. See this for example.

Yes, there is some modifications in the pipe... Helped by @vincent-d I have modified this glue-code. Thanks!

[javierfileiv]

Hello, well I worked this PR a little bit but I'm having issues with the example on native build. Even using the tap interface I can't reach a local mosquitto broker server. If someone can help me, would be awesome. I already tested the framework on a private board and it's working fine but wanted to build an example for native. I tried to contact @miri64 but I think she might be on holidays, what it is normal due to this time of the year :). Have great holidays to all of you.

[pokgak]

I had a similar problem when testing #10222 on native. Try one of these:

1. Listen on all interfaces ([::]) on the MQTT broker. OR
2. Set a 2001:* address on tapbr0 and in the RIOT node:

# On Linux
$ sudo ip a a 2001:db8::1/64 dev tapbr0

# On RIOT, get <if_id> by running `ifconfig`
> ifconfig <if_id> add 2001:db8::2/64

# Try ping from RIOT to the server/broker
> ping6 2001:db8::1

[javierfileiv]

I think that I'm not understanding the tap interface and tap bridge concept... Isn't the tap0 the one that RIOT uses when passing tap0 as parameter? Why are you modifying the ip address of tapbr0?

[javierfileiv]

@pokgak regarding ifconfig add, I don't know how to use as I don' t use gnrc becayse I need TCP packets. I'm using LWIP

[pokgak]

I might be wrong, but the way I understand it tapbr0 is a bridge to connect the real network (localhost, eth0, wlan, etc) to the virtual network (tap0, tap1), so we just need to connect this two network together. Link-local IPv6 cannot be routed between two networks, that's why we need a 2001:* (global?) address for tapbr0 so that it is routable.

About LWIP TCP, I have never used it myself but If there is ifconfig command on the RIOT shell, you can type ifconfig -h to get instructions how to use it.

[javierfileiv]

@pokgak when you tested #10222 did you use this type of configuration? Is there any test on RIOT where I can see how it works?

[pokgak]

I usually set the server on linux to listen to any (::) address.

Is there any test on RIOT where I can see how it works?

I'm not sure about tests but there is the emcute MQTT-SN implementation and example application by @haukepetersen.

[javierfileiv]

Thanks @pokgak , right now I have not much time to test it but I will do it as soon as I have a gap on my schedule. Have a nice day

[aabadie]

It would be awesome if this package could be merged one day. I just had a brief look and I think the way the package is built still needs work. I haven't look that much in detail at the networking glue code but it seems quite good at first sight.

[gschorcht]

Should I squash??

For my part yes. @gschorcht @aabadie what do you say?

One of my change requests is still not addressed. But it can be squashed directly.

[gschorcht]

The problem is the - in the identifier. Changing it from pkg_paho-mqtt to pkg_paho_mqtt in both files works as expected. For consistency, I would prefer to have a doc.txt file as for all other packages which documents the package and groups the related files.

[javierfileiv]

Should I squash??

For my part yes. @gschorcht @aabadie what do you say?

One of my change requests is still not addressed. But it can be squashed directly.

It was addressed, I just forgot to resolve the conversation :$

[javierfileiv]

Ok, I think we are good now, right? :D I squash??

[gschorcht]

Should I squash??

For my part yes. @gschorcht @aabadie what do you say?

One of my change requests is still not addressed. But it can be squashed directly.

It was addressed, I just forgot to resolve the conversation :$

No, it is not addressed. It ist still

RIOT/examples/paho-mqtt/Makefile

Line 56 in 424e779

ifneq (,$(filter arch_esp32,$(FEATURES_USED)))

but it has to be

    ifneq (,$(filter arch_esp,$(FEATURES_USED)))

[gschorcht]

It is still not addressed.

[miri64]

Header guards also need to be adapted

Comments were addressed.

[gschorcht]

I have tested it again with ESP8266 and ESP32. Works as expected. I have a last change request but it can squashed directly. Please squash after this last change.

[javierfileiv]

Squash done. What's the last change about?

[miri64]

@aabadie are you fine with the state of this PR?

[gschorcht]

Squash done. What's the last change about?

Hm strange, the requested changes were not submitted last time. Anyway, here they are again. You can squash this small change directly.

[javierfileiv]

STACK SIZE updated !

[javierfileiv]

seems fine for me

[javierfileiv]

Close to the merge I would like to say thank you very much for all the support, @aabadie @miri64 @gschorcht . Hopefully, if merged, this will be my first open source contribution. :)

[gschorcht]

Looks good now.

[miri64]

Close to the merge I would like to say thank you very much for all the support, @aabadie @miri64 @gschorcht . Hopefully, if merged, this will be my first open source contribution. :)

Thank you, for your patience :)

[aabadie]

Hopefully, if merged, this will be my first open source contribution. :)

I hope you enjoyed it and learned new things :)

[javierfileiv]

Hopefully, if merged, this will be my first open source contribution. :)

I hope you enjoyed it and learned new things :)

No doubts! :)