[Bug]: Server log messages are duplicated

[jvstme]

Steps to reproduce

1. Install dstack from PyPI.
2. Run dstack server.

Actual behaviour

[19:37:32] INFO     Applying ~/.dstack/server/config.yml...                                                                                                                                    
           INFO     Applying ~/.dstack/server/config.yml...                                                                                                                                    
[19:37:33] INFO     dstack._internal.server.services.plugins:77 Found not enabled builtin plugin rest_plugin. Plugin will not be loaded.                                                       
           INFO     dstack._internal.server.services.plugins:77 Found not enabled builtin plugin rest_plugin. Plugin will not be loaded.                                                       
           INFO     dstack._internal.server.app:163 Job network mode: HOST_WHEN_POSSIBLE (2)                                                                                                   
           INFO     dstack._internal.server.app:163 Job network mode: HOST_WHEN_POSSIBLE (2)                                                                                                   
           INFO     The admin token is ***                                                                                                                    
           INFO     The admin token is ***                                                                                                                    
           INFO     The dstack server 0.19.30 is running at http://127.0.0.1:3000                                                                                                              
           INFO     The dstack server 0.19.30 is running at http://127.0.0.1:3000

Expected behaviour

[19:37:32] INFO     Applying ~/.dstack/server/config.yml...                                                                                                                                    
[19:37:33] INFO     dstack._internal.server.services.plugins:77 Found not enabled builtin plugin rest_plugin. Plugin will not be loaded.                                                       
           INFO     dstack._internal.server.app:163 Job network mode: HOST_WHEN_POSSIBLE (2)                                                                                                   
           INFO     The admin token is ***                                                                                                                    
           INFO     The dstack server 0.19.30 is running at http://127.0.0.1:3000                                                                                                              

dstack version

0.19.30

Server logs

Additional information

• Introduced in 0.19.30.
• If running from source code, only reproducible with DSTACK_SERVER_RELOAD_DISABLED=1. Always reproducible when running from the PyPI build.
• Setting DSTACK_SERVER_LOG_FORMAT=standard results in messages being duplicated in different formats.

[19:42:29] INFO     Applying ~/.dstack/server/config.yml...                                                                                                                                    
INFO 2025-09-30T19:42:29.750 dstack._internal.server.app Applying [link=file:///root/.dstack/server/config.yml]~/.dstack/server/config.yml[/link]...
           INFO     dstack._internal.server.services.plugins:77 Found not enabled builtin plugin rest_plugin. Plugin will not be loaded.                                                       
INFO 2025-09-30T19:42:29.835 dstack._internal.server.services.plugins Found not enabled builtin plugin rest_plugin. Plugin will not be loaded.
           INFO     dstack._internal.server.app:163 Job network mode: HOST_WHEN_POSSIBLE (2)                                                                                                   
INFO 2025-09-30T19:42:29.844 dstack._internal.server.app Job network mode: HOST_WHEN_POSSIBLE (2)
           INFO     The admin token is ***                                                                                                                    
INFO 2025-09-30T19:42:29.846 dstack._internal.server.app The admin token is ***
           INFO     The dstack server 0.19.30 is running at http://127.0.0.1:3000                                                                                                              
INFO 2025-09-30T19:42:29.847 dstack._internal.server.app The dstack server 0.19.30 is running at http://127.0.0.1:3000