vmod_rers (Regular Expression in RuSt)

This is a vmod for varnish, allowing you to expand on what the native VCL regex can do.

Notably, it offers dynamic regex compilation backed by a LRU cache to speed processing up while limiting the memory footprint. On top of this, it supports named capturing groups which simplifies the handling of complex regex.

As usual, the full VCL API is described in vmod.vcc, and it you need help, you can find me as guillaume on the varnish discord server.

VCL Example

import rers;

sub vcl_init {
	new re_cache = rers.init(100);
}

sub vcl_recv {
	if (re_cache.is_match(req.url, "admin")) {
		return (pass);
	}
	if (re_cache.capture(req.http.authorization, "(\w+) (\w+)") {
		set req.http.auth_type = re_cache.group(1);
		set req.http.auth_credential = re_cache.group(2);
	}
}

Requirements

You'll need:

cargo (and the accompanying rust package)
python3
the varnish development libraries/headers

Version matching

Depending on which varnish version tou are targeting, select the right vmod_rers version (available as git tags, and as releases).

vmod-rers	varnish
v0.0.8	7.4
v0.0.7	7.3
v0.0.6	7.3
v0.0.5	7.2
v0.0.4	7.0
v0.0.3	7.0
v0.0.2	7.0
v0.0.1	7.0

Build and test

With cargo only:

cargo build --release
cargo test --release

The vmod file will be found at target/release/libvmod_rs_template.so.

Alternatively, if you have jq and rst2man, you can use build.sh

./build.sh [OUTDIR]

This will place the so file as well as the generated documentation in the OUT directory (or in the current directory if OUT wasn't specified).

Packages

To avoid making a mess of your system, you probably should install your vmod as a proper package. This repository also offers different templates, and some quick recipes for different distributions.

All platforms

First it's necessary to set the VMOD_VERSION (the version of this vmod) and VARNISH_VERSION (the Varnish version to build against) environment variables. It can be done manually, or using cargo and jq:

VMOD_VERSION=$(cargo metadata --no-deps --format-version 1 | jq '.packages[0].version' -r)
VARNISH_MINOR=$(cargo metadata --format-version 1 | jq -r '.packages[] | select(.name == "varnish-sys") | .metadata.libvarnishapi.version ')
VARNISH_PATCH=0
VARNISH_VERSION="$VARNISH_MINOR.$VARNISH_PATCH"

# or
VMOD_VERSION=0.0.1
VARNISH_VERSION=7.0.0

Then create the dist tarball, for example using git archive:

git archive --output=vmod_rs_template-$VMOD_VERSION.tar.gz --format=tar.gz HEAD

Then, follow distribution-specific instructions.

Arch

# create a work directory
mkdir build
# copy the tarball and PKGBUILD file, substituing the variables we care about
cp vmod_rs_template-$VMOD_VERSION.tar.gz build
sed -e "s/@VMOD_VERSION@/$VMOD_VERSION/" -e "s/@VARNISH_VERSION@/$VARNISH_VERSION/" pkg/arch/PKGBUILD > build/PKGBUILD

# build
cd build
makepkg -rsf

Your package will be the file with the .pkg.tar.zst extension in build/

Alpine

Alpine needs a bit of setup on the first time, but the documentation is excellent.

# install some packages, create a user, give it power and a key
apk add -q --no-progress --update tar alpine-sdk sudo
adduser -D builder
echo "builder ALL=(ALL) NOPASSWD: ALL" > /etc/sudoers
addgroup builder abuild
su builder -c "abuild-keygen -nai"

Then, to actually build your package:

# create a work directory
mkdir build
# copy the tarball and PKGBUIL file, substituing the variables we care about
cp vmod_rs_template-$VMOD_VERSION.tar.gz build
sed -e "s/@VMOD_VERSION@/$VMOD_VERSION/" -e "s/@VARNISH_VERSION@/$VARNISH_VERSION/" pkg/arch/APKBUILD > build/APKBUILD

su builder -c "abuild checksum"
su builder -c "abuild -r"

gquintard/vmod_rers