esy-libpng

esy-libpng is the package, libpng, packaged for esy.

Why

esy can not only fetch and install Reason and OCaml libraries and tools, but also those written in C. This extends reproducibility benefits to packages written in C, like skia, libffi, pkg-config etc. Users don't have to install them separately, nor have to worry if they have installed the correct version. Read more at the docs about benefits for opting for esy packages.

How to use esy-libpng?

esy-libpng can be used from both NPM and directly from Github.

From NPM

esy-libpng is deployed on NPM can be found here.

You can simply run esy add esy-libpng to install it, or specify it in package.json and run esy.

{
  "dependencies": {
+   "esy-libpng": "*"
  }
}

Directly from Github

{
  "dependencies": {
    "esy-libpng": "esy-packages/esy-libpng"
  }
}

i.e. <GITHUB_ORG or USERNAME>/<REPO NAME>

To use a specific commit,

  "dependencies": {
+   "esy-libpng": "esy-packages/esy-libpng#<commit hash>"
  }

How to package for esy?

For the experienced

The gist Specify the configure and build commands in esy.build property of esy.json and the install step in esy.install. If the package builds "in source", set esy.buildsInSource property to true. Use $cur__install environment variable to set the install location.

See docs for reference.

The CI will take care of fetching the sources and creating an NPM package for you. See script.js to see how it works.

You can download it or auto publish via CI.

For beginners

Note: you'll need Node.js for this tutorial. If you're experienced with bash, you can use it instead.

Fundamentally, packaging for esy works like in other Linux distros, except ofcourse, such that packages become available on MacOS and Windows too.

You would typically have to specify the instructions to build the package in the esy.json. For example, everyone's favourite http tool, curl, needs the following instructions (as described on their website)

./configure
make
make install

Many packages have similar instructions!

Configure and build steps are specified in the esy.build property in the esy.json and install steps in esy.install. Example,

{
  "esy": {
    "build": [
	  "./configure",
	  "make"
	],
	"install": [
	  "make install"
	]
  }
}

Testing and making sure the package works as expected

Note

There's esy-package in the works to automate parts of this and make writing packages easier.

To test if the package works, we recommend an end-to-end test by publishing it to local verdaccio, and using the package with a package.json or esy.json depends on it.

{
  "dependencies": {
    esy-libpng": "*"
  }
}

And pointing esy to the local npm registry

esy i --npm-registry http://localhost:4873
esy b

If the package is a library, it's a good idea to write a small program to actually check if the library works. Referring how the corresponding package is being tested in Homebrew or Arch Linux.

Checkout ci-test.sh for reference, used on the CI.