same mqtt client id - unable to reconnect

[meriksk]

v1.0.3
for my web-app I need to store mqtt client id in the cache for a short time (i.e. 1 minute). Stream works well for the first time. Then I am unable to connect with a new RTCPeerConnection but the same mqtt client id.

command:
pi_webrtc --use_libcamera --fps=10 --width=1280 --height=960 --hw_accel --no_audio --mqtt_host=**** --mqtt_port=8883 --mqtt_username=**** --mqtt_password=**** --uid=device-100000003a0a2f6e

console output:

first try:

[0:07:06.813328372] [1576]  INFO Camera camera_manager.cpp:325 libcamera v0.3.2+99-1230f78d
[0:07:06.848779699] [1584]  WARN RPiSdn sdn.cpp:40 Using legacy SDN tuning - please consider moving SDN inside rpi.denoise
[0:07:06.850852454] [1584]  INFO RPI vc4.cpp:447 Registered camera /base/soc/i2c0mux/i2c@1/imx708@1a to Unicam device /dev/media0 and ISP device /dev/media2
[libcamera_capturer] camera id: /base/soc/i2c0mux/i2c@1/imx708@1a
[libcamera_capturer] camera validated format: 1280x960-YUV420.
[libcamera_capturer]   width: 1280, height: 960, stride: 1280
[0:07:06.851493039] [1576]  INFO Camera camera.cpp:1197 configuring streams: (0) 1280x960-YUV420
[0:07:06.851839554] [1584]  INFO RPI vc4.cpp:622 Sensor: /base/soc/i2c0mux/i2c@1/imx708@1a - Selected sensor format: 1536x864-SBGGR10_1X10 - Selected unicam format: 1536x864-pBAA
=> Set sdp success!
=> Set sdp success!

... stream is connected ...

reloading the page - initializing new RTCPeerConnection (same mqtt client id):

... not response to offer ...
... no console output for 30s ...

=> Set sdp failed! Failed to set remote offer sdp: Called in wrong state: closed
[rtc_peer] Error: INVALID_STATE; PeerConnection cannot create an answer in a state other than have-remote-offer or have-local-pranswer.
[rtc_peer] Error: Failed to apply the received candidate!
[rtc_peer] Error: Failed to apply the received candidate!
[rtc_peer] Error: Failed to apply the received candidate!

... no console output for 30s, still unable to connect ...

=> Set sdp success!
=> Set sdp success!

after approx. 60s of the first connection I am able to connect again

[TzuHuanTai]

Oh, because I use a hash map to cache a pair of an MQTT client and an RTC peer in v1.0.3, and the hash map is refreshed very 60s.
I assumed mqtt client would disconnect after webrtc connection was established, but I didn't consider the possibility of having the same client ID.

[TzuHuanTai]

The updated code has been integrated into the main branch, and this issue will be resolved in the next release.