Guix: creating a package from a binary

Let's start with the simple metadata fields: name, version, synopsis, description, license, home-page. Those are mostly informational and some of those optional.

In our case, these aren't very important as we will not distribute the package. Some of those fields are used to generate the documentation when searching for package.

If you intend to distribute a package, I would encourage you to be a bit more descriptive than me!

(define caddy
  (package
    (name "caddy")
    (version "2.11.4")
    (home-page "https://caddyserver.com")
    (synopsis "Web server with automatic HTTPS")
    (description "Caddy is an extensible web server with automatic TLS.")
    (license asl2)))

With this easy task out the way, we only need to address two more parts: where to get the binary from, and how to "build" it.

In this case, for simplicity's sake, we are packaging the binary instead of building Caddy from source.

To do so, we use the source field which contains an <origin> record. The <origin> record is described in detail in this section of the documentation.

Our case is very simple: we fetch the binary.

I am using the GitHub release page to get the binary, and the url-fetch method.

(source (origin
         (method url-fetch)
         (uri (string-append
               "https://github.com/caddyserver/caddy/releases/download/v"
               version "/caddy_" version "_linux_amd64.tar.gz"))
         (sha256
          (base32 "1fbvxj6mifdqhwm5s1f8snr805k0anllzlri7cg9l61rgj8vyzsj")))

Two things to note here:

• I'm constructing the URL based on the version. This is optional.
• I hard coded the target platform, amd64. You might need to adapt it, or better, use a "system" variable like I have done for the version.

We now have the metadata and the source. The last missing piece is the building instructions.

Guix offers out of the box multiple build systems for different use cases. For example, the gnu build system is designed for projects following the GNU coding standard. You will find many others build systems such as node, zig or golang.

Each build system exposes arguments to customise the build process to your need.

The <package> record can also include inputs, which specifies the build-time or run-time dependencies of the package.

Our case is simple, there are no dependencies as the package is already built. We simply need to copy the executable to the right location.

Guix has a build system for this, the copy-build-system, which expose only one argument: install-plan.

The install-plan argument is used to instruct where to copy files.

In our use case, we simply want to copy the binary into the packages' /bin directory.

(build-system copy-build-system)
(arguments
 (list #:install-plan #~'(("caddy" "bin/"))))

Note that the binary isn't installed in the user or root binary folder. It will be installed in the store, at /gnu/store/...-caddy-2.11.4/bin/caddy

To make it available to your user, you will need to add it as a user package, a system package or within a service.

In this case, I intend to use it for my caddy-service which I'll go over in a future post.