Consistent warnings in Grafana logs: level=warn msg="Could not create user agent" error="invalid user agent format"

Symptoms

• Followings warnings shows consistently in grafana logs i.e. /var/log/grafana/grafana.log:

  CONFIG_TEXT: 2025-07-20T10:38:03.002121+02:00 vps grafana[825645]: logger=plugin.context t=2025-07-20T10:38:03.001732463+02:00 level=warn msg="Could not create user agent" error="invalid user agent format"
  2025-07-20T10:38:03.002945+02:00 vps grafana[825645]: logger=plugin.context t=2025-07-20T10:38:03.002852175+02:00 level=warn msg="Could not create user agent" error="invalid user agent format"
  2025-07-20T10:38:06.001770+02:00 vps grafana[825645]: logger=plugin.context t=2025-07-20T10:38:06.0009356+02:00 level=warn msg="Could not create user agent" error="invalid user agent format"

• Plesk Monitoring and Grafana Service works and such warnings do not obstruct its functioning

Cause

Under investigation within the scope of Bug#EXTPLESK-9121

Resolution

No fix available at the moment. As a workaround, the logging level in grafana can be decreased to log errors only using the following steps:

1. Connect to the Plesk server via SSH.

2. Edit the grafana configuration using any editor like vi:

   # vi /etc/grafana/grafana.ini

3. Edit the logging from warn to error as shown below:

   CONFIG_TEXT: #################################### Logging ##########################  
   [log] 
   # Either "console", "file", "syslog". Default is console and file 
   # Use space to separate multiple modes, e.g. "console file" 
   ;mode = console file
   
   # Either "debug", "info", "warn", "error", "critical", default is "info" 
   level = error

4. Restart Grafana service:

   # service grafana-server restart