Numbering of bridged endpoints (CON-761)

[elektro-NIK]

I am working on developing a bridge between Matter and non-Matter devices.

My bridge must be able to dynamically create and delete bridged endpoints. I do this using the esp_matter_bridge::create_device and esp_matter::endpoint::destroy APIs and I noticed that endpoint IDs for new devices are issued one after the other, even if there are endpoints released (using destroy) before that. This leads to the fact that when I create and delete device IDs, they reach the maximum number for the bridge and no more are created.

I've researched this behavior a bit, and it's because, in esp_matter_core.cpp, in the endpoint::create function, the min_unused_endpoint_id field is always incremented and stored in NVS.

Is this the correct behavior and is there any way around it?

[wqx6]

Yes, the SPEC says we should select endpoint address for dynamic endpoint byincrementing from the highest previously (ever) used endpoint address. And the SPEC also says that when the endpoint address reaches 65535(UINT16_MAX), it MAY wrap around to the lowest unused endpoint address. We are planning to add this logic later.

[elektro-NIK]

Ok, thank you.

I continued experimenting and ran into the following problem. My devices stop being created after 125 creation-deletions. Because 2 namespaces are used for each endpoint, and with esp_matter_bridge::erase_bridged_device_info, the nvs_erase_all API is called, which erases all key-value pairs, but the namespace itself remains, and NVS can only have 255 namespaces.

Is there a way around this?

[wqx6]

@elektro-NIK Thanks for report. Will fix it ASAP.

[dhrishi]

This has been fixed with 98c6e80