Add Caddyfile lexer

[francislavoie]

Closes #338

So, I definitely have no idea what I'm doing 😄

I spent most of the day hacking on this, seems like it's in decent shape, but who knows. There's probably a much better way to approach it, but this is what I came up with after trying to resolve a ton of edge cases.

I was testing it doing a spam of:

$ go build && ./chroma -l caddyfile Caddyfile --html -s tango > test.html

and

$ go build && ./chroma --trace -l caddyfile Caddyfile

I implemented two lexers here because we have two main usecases - displaying a full Caddyfile config, and showing just partials (matchers and directives) in documentation and such.

I'm not certain which token types to pick, I just kinda with what sorta made sense and made it look pretty in the output 🤷‍♂️

I'd very much appreciate any tips/feedback on this. 🎉

Here's a couple somewhat representative config examples and screenshots. Caddyfiles are very rarely this long or complicated, but these show most of the tricky elements.

{
	debug
}

example.com, fake.org {
	root * /srv

	route {
		# Add trailing slash for directory requests
		@canonicalPath {
			file {
				try_files {path}/index.php
			}
			not path */
		}
		redir @canonicalPath {path}/ 308

		# If the requested file does not exist, try index files
		@indexFiles {
			file {
				try_files {path} {path}/index.php index.php
				split_path .php
			}
		}
		rewrite @indexFiles {http.matchers.file.relative}

		# Proxy PHP files to the FastCGI responder
		@phpFiles {
			path *.php
		}
		reverse_proxy @phpFiles unix//var/run/php7.4-fpm.sock {
			transport fastcgi {
				split .php
			}
		}
	}

	@encode_exts {
		path / *.html *.js *.css *.svg
	}

	header {
		X-Content-Type-Options nosniff
		X-XSS-Protection "1; mode=block"
		X-Robots-Tag none
		Content-Security-Policy "frame-ancestors 'self'"
		X-Frame-Options DENY
		Referrer-Policy same-origin
	}
	
	@singleLine not path /matcher
	respond @singleLine "Awesome."

	file_server
}

Another:

# Caddy v2 file for Kirby 2 & Kirby 3 local sites
# v0.1.0
# 2020/05/10
#=====================
# Global Block
{
  email youremail@domain.tld
  local_certs
}

# Snippets
# Common server snippet use 'import common'
(common) {
  encode gzip
  php_fastcgi localhost:9000
  tls internal
  file_server
  header * {
    # You may want some other header options...
    X-Frame-Options "DENY"
    X-XSS-Protection "1; mode=block"
    X-Content-Type-Options "nosniff"
    X-Frame-Options "SAMEORIGIN"
  }
}

#---------------------
# Kirby 2 & 3 common snippet use 'import kirby'
(kirby) {  
  @blocked {
    path *.txt *.md *.mdown /site/* /kirby/*
  }
  redir @blocked /
}

#---------------------
# Kirby 2 snippet use 'import kirby2'
(kirby2) {
  # /panel files
  handle /panel* {
    try_files {path} {path}/ /panel/index.php?{uri}&{query}
  }
  
  @notPanel {
    not path /panel*
  }
  handle @notPanel {
    try_files {path}/ /index.php?&{query}
  }
}

#---------------------
# Cachebuster rewrite style.123213.css -> style.css 'import cachebuster'
(cachebuster) {
  @cachedFiles {
      not file
      path_regexp cached ~*(.+)\.(?:\d+)\.(js|css|jpg|svg|png)
  }
  rewrite @cachedFiles {http.regexp.cached.1}.{http.regexp.cached.2}
}

#=====================
# Virtual Hosts - domains need to be added to your hosts file

kirby2site.test:443 {
  root * /PATH_TO_SITE/kirby2site
  import common
  import kirby
  import kirby2
}

kirby3site.test:443 {
  root * /PATH_TO_SITE/kirby3site
  import common
  import kirby
}

kirby2cachebustersite.test:443 {
  root * /PATH_TO_SITE/kirby2cachebustersite
  import common
  import cachebuster
  import kirby
  import kirby2
}

Screenshots:

Another:

[mholt]

This is beautiful. 😍

[alecthomas]

Very nice! Please add a test file per the instructions in lexers/README.md.

Overall looks pretty good, I'll come back with some suggestions shortly.

[alecthomas]

No need to make this or the other intermediate values public.

[alecthomas]

LGTM, merged. Any followups just send a new PR.

[alecthomas]

Thanks!

[francislavoie]

Thank you @alecthomas!!

I already made a PR to update the Caddy website with this caddyserver/website#41

I definitely will have a followup PR soon, I noticed a few edgecases that aren't well covered.