How to separate 4xx/5xx error logs into a different file?

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1

Hi everyone,

I’m currently migrating from Apache to Caddy on a test EC2 server before deploying it in production. The last piece I’m struggling with is separating HTTP error logs (specifically 4xx and 5xx responses) into a dedicated log file.

My goal is to log all 4xx and 5xx responses (like 404, 403, 500, etc.) into a separate file from normal access logs. Any help or working examples would be greatly appreciated!

2

Could you share your Caddyfile? It’ll be much easier to help with your specific situation rather than trying to guess all the possible scenarios.

3 
(logging) {

    log {args[0]} {
        output file /var/log/website/developer-access-{args[0]}.log {
            mode 664
        }
    }

    log_skip /check.html
}


https://website-developer.server.it {

    root /home/ubuntu/environment/e-website/public

    @admin path /admin /admin/* 

    import headers
    import caching
    import certificate domain.it
    import encoding
    import logging frontend
    import processing

    log admin {
        output file /var/log/website/developer-access-admin.log {
            mode 664
        }
        no_hostname
    }

    handle @admin {
        log_name admin
    }
}

I have file log for admin request and another for frontend request I need file separate log for request with 4xx and 5xx

4

I think you’re almost there.

This might be possible to do more efficiently, but here’s a quick example I just put together. Feel free to adjust it to your needs:

:80 {

	log log4xx5xx {
		output file /tmp/caddy-error4xx5xx.log {
			mode 664
		}
		no_hostname
	}

	intercept {
		@4xx-5xx status 4xx 5xx
		handle_response @4xx-5xx {
			log_name log4xx5xx
		}
	}
		
	respond /4xx 403
	respond /5xx 503
	respond 200

}

If you want to have separate log files for 4xx and 5xx errors, you can repeat the same setup for each status group individually.

2 Likes
5

Thank you @timelordx is perfect !

# Define global
{
    log {
        output file /var/log/website/developer-system.log {
            mode 664
        }
    }
}

# Define snippet

(logging) {

    log {args[0]} {
        output file /var/log/website/developer-access-{args[0]}.log {
            mode 664
        }
        {args[1:]}
    }

    log_skip /check.html
}

# Define subdomain

https://website-developer.server.it {

    root /home/ubuntu/environment/e-website/public

    import headers
    import caching
    import certificate mydomain.it
    import encoding
    import processing

    import logging frontend
    import logging admin no_hostname
    import logging error no_hostname

    intercept {
        @status-error status 4xx 5xx
        handle_response @status-error {
             log_name error
         }
    }

    handle @admin {
        log_name admin
    }
}

I have system log, access admin log, frontend log and response errors log :smiley:

9697 Jun 28 02:52 developer-access-admin.log
1875 Jun 28 02:53 developer-access-error.log
2097 Jun 28 02:53 developer-access-frontend.log
9752 Jun 28 03:00 developer-system.log
1 Like