Docker logs to file does not capture all logging?

[olavt]

It seems to be an issue with how logs are done.

When I do a "docker logs matter-server > a.log", not all logging are written to a.log. A lot of the logging are just written to the console.

Here are some examples of logging that are not written to the log file:

2024-03-18 11:16:33 (Dummy-2) CHIP_ERROR [chip.native.DMG] Failed to establish CASE for re-subscription with error 'src/protocols/secure_channel/CASESession.cpp:553: CHIP Error 0x00000032: Timeout'
2024-03-18 11:16:33 (MainThread) INFO [matter_server.server.device_controller.node_2] Previous subscription failed with Error: 50, re-subscribing in 124563 ms...
2024-03-18 11:18:02 (Dummy-2) CHIP_ERROR [chip.native.EM] Failed to Send CHIP MessageCounter:71477996 on exchange 64626i sendCount: 4 max retries: 4
2024-03-18 11:18:06 (Dummy-2) CHIP_ERROR [chip.native.SC] CASESession timed out while waiting for a response from the peer. Current state was 4
2024-03-18 11:18:06 (Dummy-2) CHIP_ERROR [chip.native.DMG] Failed to establish CASE for re-subscription with error 'src/protocols/secure_channel/CASESession.cpp:553: CHIP Error 0x00000032: Timeout'
2024-03-18 11:18:06 (MainThread) INFO [matter_server.server.device_controller.node_2] Previous subscription failed with Error: 50, re-subscribing in 119886 ms...
2024-03-18 11:20:42 (MainThread) INFO [root] Re-subscription succeeded!
2024-03-18 11:20:42 (MainThread) INFO [matter_server.server.device_controller.node_2] Re-Subscription succeeded
2024-03-18 11:21:09 (Dummy-2) CHIP_ERROR [chip.native.DMG] Time out! failed to receive report data from Exchange: 64630i
2024-03-18 11:21:09 (MainThread) INFO [matter_server.server.device_controller.node_1] Previous subscription failed with Error: 50, re-subscribing in 277355 ms...
2024-03-18 11:28:42 (MainThread) INFO [root] Re-subscription succeeded!
2024-03-18 11:28:42 (MainThread) INFO [matter_server.server.device_controller.node_1] Re-Subscription succeeded

[agners]

Afaik, Docker logs logs to stdout what has been sent to stdout, and to stderr what has been sent to stderr. The Python logging system which the Python Matter Server uses logs to stderr by default. So if you want to forward things into a file, you'd use docker logs matter-server 2> a.log.