If you are running docker or some other container system where logs are written to stdout you should utilize whatever tooling exists to capture that output (docker logs or similar solutions).

If you are using a zip file installation or some other installation method which writes log files, you can export the system logs using this API call.

In 1.19.5, we handle most of these cases by configuring tomcat to allow certain characters to be unescaped in the URL.

https://github.com/FusionAuth/fusionauth-issues/issues/635

So an upgrade is the most straightforward way to handle this.

If you are proxying FusionAuth (behind something like nginx) you could also capture and hide any 500 errors: https://stackoverflow.com/questions/8715064/nginx-not-serving-my-error-page/8715597#8715597.

There's not really a supported way to modify the FusionAuth logging format.

In theory you could do it manually but dropping in your own version of logback.xml and adding the necessary jars to the classpath.

Here is an example of JSON with logback. https://github.com/larose/logback-json-example

I think you’d have to add in the JSON logback jar since we do not ship with it.

We use logback.

As of version 1.19.0, here is the logging pattern: <pattern>%d{"yyyy-MM-dd h:mm:ss.SSS a"} %-5level %logger{75} - %msg%n</pattern>

Older versions, prior to 1.19.0, use this pattern <pattern>%d{"MMM dd, yyyy h:mm:ss.SSS a"} %-5level %logger{75} - %msg%n</pattern>.

There is not any special logging for webhooks.

If an exception occured that would cause it not to be fired, that will be in the log. If it is not being fired and there is no exception, then it is likely that the webhook is not configured to be sent for the particular tenant that you’re using.

More about webhooks: https://fusionauth.io/docs/v1/tech/events-webhooks/