About

Demo repository exloring how to automatically provide custom bash functions/symbols to

• make recipes

• make shell function calls (i.e. $(shell ...))

What is it good for ?

When developing larger Makefile's you will recognize

• duplicated bash code within make your recipes

• large bash recipes across many lines (possible thanks to make directive .ONESHELL)

• longer bash recipe blocks will look very confusing due to the $ escaping issue

Would'nt it be nice to out source such bash code in separate shell script libraries ?

• easier maintenance

  Makefiles just consist of short recipes just calling your bash functions

  Makefile

  deploy: build
    github::release $(GIT_TAG) $(GITHUB_USER) $(GITHUB_TOKEN)

  your Bash library

  function github::release() {
    ...
  }
  export -f github::release

• testing

  Your bash scripts can be hardened by tests.

  There exist a bunch of mature shell testing frameworks like https://github.com/kward/shunit2 or bats for testing bash code

• reusable code

  Your bash functions can now be reused in other slightly different projects.

I think the answer is a clear : Y.E.S. !

---

This repo contains some working examples implementing automatic configurable provisioning of custom bash libraries in Makefile's.

Depending on your needs you can choose wich variant works best for you.

• ./make-bash-init-script-simply-but-partly-broken/

  Contains a very simplistic effort utilizing Bash's --rcfile option to inject your bash functions to the Makefile. It has a few caveats but may be okay for smaller Makefiles.

• ./make-bash-library-injection-modular-take/ ist the GOLD solution without any caveats. This solution requires a bit more Make/Bash bootstrapping code but fit's every case

So if you don't know which one to use ... head over to the GOLD solution - it works in every case.

---

Is it used somewhere ?

I use some of the ideas implemented here in a generic make framework called pnpmkambrium by myself.

pnpmkambrium goes far beyond the technique described here - it provides

• a generic Meta Makefile maintaining monorepos for building/uploading

  • docker images

  • npm packages

  • wordpress plugins/themes

  • ...

  out of the box

• customizable by .env and .secret files.

  In most cases you don't need to write custom Makefile's - just provide .env files (for non-sensitive data) and .secrets files (for sensitive data like credentials).

• You can even extend it with your own Bash functions and Make targets/rules.

You may also have a look at my Makefile recipes in various languages GitHub repo showing how to use almost any scripting language (instead of bash) to implement Makefile recipes

Prerequisites

• GNU make

• Bash

Prior art

• https://github.com/nclsgd/makebashwrapper