Conditionals in snippets?

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1

1. The problem I’m having:

I’m using snippets in the Caddyfile in order to reuse as much configuration content as possible and to avoid copying&pasting and producing errors due to gettings those copy&paste clones out of sync.

Now I am wondering whether I can do conditionals within snippets.

Consider a Caddyfile as follows:

(logging) {
    log {
        format transform "{common_log}" ### how can I make this conditional?
        output file /var/log/caddy/{args[0]}.log {
            roll_size 10mb
            roll_keep 5
        }
    }
}

(common) {
    header {
        # Enable headers for all sites here ...
    }
    import logging {args[0]}
}

(common_proxy_https) {
    reverse_proxy {args[1]} {
        transport http {
            tls_server_name {host}
        }
    }
    import common {args[0]}
}

# Global options
{   
    import logging caddy
    events {
        on cert_obtained exec ...
    }
}

# Reverse proxies
host1.example.tld {
    import common_proxy_https service1 https://service1.local
}

host2.example.tld {
    import common_proxy_https service2 https://service2.local
}

host3.example.tld {
    import common_proxy_https service3 https://service3.local
}

I would like to keep JSON log format for the main caddy.log (via global options import logging caddy) but for the actual reverse proxies I would like to have traditional Apache access log format in order for fail2ban to work.

Therefore my question: Is it possible to have a conditional on {args[0]} != "caddy" within snippet (logging) so that the format transform "{common_log}" is only active if it is not the main caddy log?

2. Error messages and/or full log output:

No error messages, I’d like to improve Caddyfile configuration.

3. Caddy version:

$ caddy version
v2.7.4 h1:J8nisjdOxnYHXlorUKXY75Gr6iBfudfoGhrJ8t7/flI=

4. How I installed and ran Caddy:

a. System environment:

x86_64 Debian GNU/Linux

b. Command:

I diverted custom caddy according to the documentation at Build from source — Caddy Documentation

c. Service/unit/compose file:

n/a

d. My complete Caddy config:

See above.

5. Links to relevant resources:

n/a

2

Just make two snippets with different names. Like logging_json and logging_commonlog or something.

3

Yes, basically

(logging_common) {
        #level DEBUG
        output file /var/log/caddy/{args[0]}.log {
            roll_size 10mb
            roll_keep 5
        }
}

(logging_json) {
    log {
        import logging_common {args[0]}
    }
}

(logging_apache) {
    log {
        # Next line requires module caddy.logging.encoders.transform:
        format transform "{common_log}"

        import logging_common {args[0]}
    }
}

is what I am using, I was just wondering whether this repetition can be expressed a bit more concise with some kind of conditional statement.

4

Yeah you can do that. Though personally I’d probably skip the logging_common snippet cause it’s barely saving you any lines and only adding complexity (making it harder to read the config cause you need to visually jump when you read import)

5

Thanks for your replies, but also to summarize: There is nothing possible like

(logging) {
    log {
        if ({args[0]} != "caddy") {
            format transform "{common_log}"
        }

        import logging_common {args[0]}
    }
}

Or via some other syntax? Is some conditional like this planned or is it a deliberate decision not to have it?

6

It’s a deliberate decision. if is not a good idea in config.

7

Not wanting to argue here, but for other parts of the config, a “kind of” conditional exists:

    @admin {
        path /admin*
        not client_ip 192.168.1.0/24
    }
    redir @admin /

Which is basically

    if (path == "/admin*" && client_ip != "192.168.1.0/24") {
        redir /
    }

and I think this is not a bad idea either. :wink:

But again, not warning to argue, just wanting to understand. I have a - not so concise - solution and can live with it.

8

Those are request matchers, it’s runtime tests against the current request. That’s not the same thing as conditional config.

9

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