/pdfdetach

Primary LanguageRuby

PDFDetach

This repository downloads the binaries, e.g. pdfdetach and publish them back as i.e. a ruby-gem — suitable for Ubuntu 16.04, 18.04 and 20.04.

How it works?

On the target system: overloading the LD_LIBRARY_PATH variable allows to execute arbitrary binaries, abusing of that we can ship those and their required .so files within a tarfile.

  • First we setup a docker image with an particular Ubuntu version:
    • install the binary of our interest, then we use docker cp to get a copy
    • retrieve the used .so files the binary uses with ldd, also we get a copy of them
  • Now we have the binaries, they are copied inside our bin directory:
    • they are released using git worktree — it turns out you can use directories as branches, like for gh-pages we're using it for pushing final files only
    • they are ignored by default on the main repository — but a .gitignore is placed inside this new branch with bin/* to sill ignore all binaries and, i.e. !bin/20.04 to actually skip the desired version of binaries
  • The ruby-gem is written as usual but the version.rb gets rewritten on release time to match the target environment, a LIB_TARGET constant is set as i.e. 20.04 (or 18.04, etc.)
    • you don't need to modify this file, the make release task will setup that for you — also you can set MAJOR and PATCH for specific version values, the MINOR will be 20, 18 or 16 according the target runtime, e.g. make release TAG=v16 PATCH=2 MAJOR=1 will be 1.16.2
    • probably you can use something else, not just ruby — try hacking the Makefile to match another stack, just keep in mind the bin folder shouls remain inside the created directory!
    • [official release as ruby-gem is still pending...]

Makefile can be configured to fetch another binaries, see the PKG, DEPS and ARGS variables — see how dependencies are fetched on the install.sh script.

Integration tests

If you're on a system with Docker running:

  • type make to setup all docker images required
  • type make test to run the available tests on each of them

Try make dev to spawn a Bash session: once inside Ubuntu, type make check

Publishing modules

We're using Ruby as the target language, see the pdfdetach/lib/pdfdetach/main.rb file to see how the wrapper works.

The make release task will care about the versioning bits, it will commit on a separated branch each release with their respective binaries also commited.

To release a particular version try make release TAG=v16

Using this module

Until released, you can require it this way:

# Gemfile
gem 'pdfdetach', git: 'https://github.com/pateketrueke/pdfdetach.git', tag: 'v0.20.0'