Thread CoAP Observe not configuring properly.

[wkpolara]

I'm working with the OpenThread CoAP protocol in the nRF Connect SDK 2.0.0.  I started with the samples:

\ncs\v2.0.0\nrf\samples\openthread\coap_client

\ncs\v2.0.0\nrf\samples\openthread\coap_server

I've added an Observable resource on the server, to which the client subscribes (registers) to be notified on updates.  I have the following Kconfig options set:

CONFIG_OPENTHREAD_COAP=y
CONFIG_OPENTHREAD_COAP_OBSERVE=y

I've verified that these are set to 'y' in the following project build file:

\build\zephyr\.config

However, the server notifications that the Observed resource has changed do not result in the response callback on the client.  In my call stack I see the OpenThread API functions are implemented in:

   \ncs\v2.0.0\modules\lib\openthread\src\core\api\coap_api.cpp

Which calls into

   \ncs\v2.0.0\modules\lib\openthread\src\core\coap\coap.cpp

In the latter "coap.cpp" file, the sections of code dealing with "Observe" support are conditionally compiled using

#if OPENTHREAD_CONFIG_COAP_OBSERVE_API_ENABLE

However, this is set to 0, and so these Observe code is not part of the build.  If not already defined, it defaults to 0 in 

  \ncs\v2.0.0\modules\lib\openthread\src\core\config\coap.h

/**

 * @def OPENTHREAD_CONFIG_COAP_OBSERVE_API_ENABLE

 *

 * Define to 1 to enable the CoAP Observe (RFC7641) API.

 *

 */

#ifndef OPENTHREAD_CONFIG_COAP_OBSERVE_API_ENABLE

#define OPENTHREAD_CONFIG_COAP_OBSERVE_API_ENABLE 0

#endif

I determined it was not defaulting to 0, but was already defined as 0.  However, I forced it to be set by changing the header file as follows:

/**

 * @def OPENTHREAD_CONFIG_COAP_OBSERVE_API_ENABLE

 *

 * Define to 1 to enable the CoAP Observe (RFC7641) API.

 *

 */

//#ifndef OPENTHREAD_CONFIG_COAP_OBSERVE_API_ENABLE

#define OPENTHREAD_CONFIG_COAP_OBSERVE_API_ENABLE 1

//#endif

After rebuilding with this change, the Observe notifications are properly calling the response callback on the client!!

So...  how should the project configuration be set up so OPENTHREAD_CONFIG_COAP_OBSERVE_API_ENABLE is set??

It appears that either CONFIG_OPENTHREAD_COAP_OBSERVE=y is insufficient, or something else overrides it...

[Sigurd Hellesvik]

Hi,

I recommend using the Insert->Code functionality. It will make it a lot easier to read your questions.

It appears that either CONFIG_OPENTHREAD_COAP_OBSERVE=y is insufficient, or something else overrides it...

Lets start to check if something overrides this.
If a Kconfig option is overridden, it is usually a warning about it in the build log. Can you see any such warning?

Do you use VS Code?
If so, you can use the Kconfig action and search for OPENTHREAD_COAP_OBSERVE to see what this configuration is set to in the finished build.
Here you can also see which options the Kconfigs are dependent on, which is useful.

Regards,
Sigurd Hellesvik

[wkpolara]

We are using VS Code.  I checked the Kconfig for the configuration.  It appears that both the OBSERVE configuration and its dependencies are set:

I also checked the \build\zephyr\.config file and verified that all 3 were set to 'y'.  (Attaching as 'dotconfig.txt')

I checked the build log, \build\.ninja_log, and didn't find anything related to "observe" (Attaching as 'dotninja_log.txt')

This is still a mystery why the OpenThread CoAP library #define for Observe isn't getting set during the build...

Are you able to configure a build of one of the OT CoAP samples so OPENTHREAD_CONFIG_COAP_OBSERVE_API_ENABLE is set?

dotconfig.txt

dotninja_log.txt

[Sigurd Hellesvik]

Hi,

I have been able to reproduce your issue.
To figure this out, I have queried our Thread developers.

I will let you know when I know more about this.

Regards,
Sigurd Hellesvik

[wkpolara]

Sigurd,

Thank you very much for following up on this promptly.  Hopefully a resolution can be found, and I look forward to hearing your Thread developers response.

[Sigurd Hellesvik]

Hi,

What you have found is indeed a bug. Our developers inform me that it has been fixed in OpenThread upstream by https://github.com/openthread/openthread/pull/7979/files.

This will hopefully be included in our next version of the nRF Connect SDK, but for now you will have to use your workaround for the Observe functionality.

Thank you for reporting this!

Regards,
Sigurd Hellesvik