Overview

pak-c-mak is cross-platform tools used as distributed package manager for C++ libraries. This tool was inspired by maven local and maven central repositories.

How it works

pak-c-mak is used to create C++ library repositories, share C++ libraries and reuse C++ libraries for cross-platform C++ multi-module applications.

• To share C++ libraries for future re-use, it is necessary to create repository of libraries, particulary pak-c-mak repository is a git repository, wich contains pak-c-mak packages for every required C++ library, while each pak-c-mak package consists of URL to source code of C++ library, and required script to build and install that library as dependency to application.

• Sharing repository of libraries is as simple as hosting git. For open source libraries: GitHub can be used to publish repository of libraries. For proprietary libraries: corporate secure git server locked to external access can be used.

• To re-use libraries it is just necessary to add pak-c-mak repositories as url into local pak-c-mak configuration, so all packages of that repository became available. And then use pak-c-mak CLI to build and install pak-c-mak packages as CMake C++ libraries modules into cross-platform multi-module C++ application.

• pak-c-mak effectively can work with multiple pak-c-mak repositories, if another pak-c-mak repository with necessary C++ libraries already exist, using pak-c-mak it is possible to add as many references to external pak-c-mak repositories as needed.

• pak-c-mak have special mode for local development, where packages will be found in local copy first. This approach is useful to test latest local changes before publishing them into remote source code repository.

Why was it created

The intention for this tool is to bring best practices to manage single cross-platform package repository for C++ projects. Java, Rust, Python already was designed for cross-platform development and have all necessary tools for that, however situation around C++ is different, C++ has longer history than any of these languages. C++ based platforms evolved independently to each other, and as a result there is no single cross-platform package managers for C++, instead 20 platform dependent exists. The intention for pak-c-mak is to make a single package manager that will fit to any platform.

In Java enterprise worlds, where web application could be very complex and contains hundreds and sometime up to thousand of transitive dependencies. Java binary executable format already made in that way, so different binary module already compatible even if they compiled for different platforms. So it makes possible for Java, to keep central repository for cross-platform binary artifacts like Maven central repository. Using java eco system it is possible to build an application by executing single command on any platform where only JDK is installed. Commonly adopted build tools like Maven and Gradle with support of maven repositories can be used for that.

In C++ worlds, CMake is commonly adopted tool for cross-platform module build, however maintaining binary compatibility between artifacts for different platform and C++ compiler versions is tricky thing. In C++ cross-platform development world it is easier to keep compatibility at source code level, and do the build for every platform independently, and keep series of binaries instead of creating single universal binary for every configuration of platform. As example: googletest, boost and other recommends just to download library source coded and put it into project. It is still possible to install googletest or boost using deb manager for Ubuntu, vcpkg for Windows or etc, but in this case it will be platform dependent way, project can be distributed to platform only with compatible package repository, and it will not be cross-platform approach.

The cross-platform central binary repository for Cross-Platform C++ will never happen, however based on Rust experience, which has same limitation like C++, it is efficient to manage dependencies as modules with buildable source code.

Solution

Git and CMake already provides all necessary tools for cross-platform C++ build and compilation.

pak-c-mak is simply set of script that provide single command line interface same for any platform, eliminating usage difference that exists for CLI and scripting on different platforms.

Git is distributed version control system.

• On Linux it is just DVCS.
• On Windows it is also provides as dependency bash eco system, that is enough to write cross platform scripts for Linux, Unix, Windows, Mac is etc.

CMake is perfect tool for C++ that can be used to install binaries of C++ libraries into cross-platform way.

Features

pak-c-mak provides following features:

• Package manager for C++ modules and dependencies between them.
• Local build cache repository to install built target, decoupled from OS binaries.
• pak-c-mak repositories: Git based repository to keep packages and profiles.
• pak-c-mak package - reference to C++ CMake based module's source codes and script to build it and install into local binary repository for future use.
• Profiles to define different preset for built configuration.
• Two ways of use:
  • Distribution mode: Automated build from remote git repositories. C++ modules are download from remote git repositories.
  • Development mode: Used to debug local changes to C++ modules. C++ modules are found on local workstation.

For complete command list please run help command: pak-c-mak help

Requirements

pak-c-mak requires these software installed before starting use of pak-c-mak:

• CMake - https://cmake.org/
• Git - https://git-scm.com/
• C++ Build Tool - one of built tool compatible with CMake generators, more info about CMake generators can be found here: https://cmake.org/cmake/help/v3.0/manual/cmake-generators.7.html
  • on Windows it could be MS Visual Studio
  • on Linux it could be build-essential package
• bash utilities
  • dirname
  • perl
  • sed

Supported Platforms

• Windows
• Linux
• OS X [not tested yet]
• BSD Unix [not tested yet]

Examples

pak-c-mak example is presented by pak-c-mak-demo-app, which have googletest as third-party dependency, and pak-c-mak-demo-repo that contains packages to build pak-c-mak-demo-app and googletest.

• pak-c-mak-demo-repo - https://github.com/amidukr/pak-c-mak-demo-repo
• pak-c-mak-demo-app - https://github.com/amidukr/pak-c-mak-demo-app
• googletest - is very nice framework for C++ unit testing created by Google, and is used as example of third-party dependency: https://github.com/google/googletest

Installing pak-c-mak-demo-app

Installing required packages for pak-c-mak

sudo apt-get update
sudo apt-get -y install git
sudo apt-get -y install cmake
sudo apt-get -y install build-essential

Cloning pak-c-mak

git clone https://github.com/amidukr/pak-c-mak
  Cloning into 'pak-c-mak'...
  ...

Adding pak-c-mak demo repository with packages and profiles

./pak-c-mak/pak-c-mak add-repo pak-c-mak-demo-repo https://github.com/amidukr/pak-c-mak-demo-repo master

Verifying if packages are successfully installed.

./pak-c-mak/pak-c-mak list
  googletest
  pak-c-mak-demo-app
  pak-c-mak-demo-app-with-deps

Building and installing googletest

./pak-c-mak/pak-c-mak install googletest
  Cloning into '/home/vagrant/pak-c-mak-test/pak-c-mak/pak_c_mak_tmp/downloads/packages/googletest'...
  ...
  [100%] Built target gtest_main
  Install the project...
  -- Install configuration: ""
  -- Installing: /home/vagrant/pak-c-mak-test/pak-c-mak/cache/lib/libgmock.a
  -- Installing: /home/vagrant/pak-c-mak-test/pak-c-mak/cache/lib/libgmock_main.a
  ...

Building and installing pak-c-mak demo application

./pak-c-mak/pak-c-mak install pak-c-mak-demo-app
  Cloning into '/home/vagrant/pak-c-mak-test/pak-c-mak/pak_c_mak_tmp/downloads/packages/pak-c-mak-demo-app'...
  ...
  [100%] Built target pak_c_mak_demo_app_executable
  Install the project...
  -- Install configuration: ""
  -- Installing: /home/vagrant/pak-c-mak/cache/lib/libpak_c_mak_demo_app_library.a

Verifying that pak-c-mak demo application successfully installed.

./pak-c-mak/cache/bin/pak_c_mak_demo_app_executable
  MyHoldVariable of MyHolderClass

Development Mode

Cloning pak-c-mak demo application sources

git clone https://github.com/amidukr/pak-c-mak-demo-app
  Cloning into 'pak-c-mak-demo-app'...

Updating pak-c-mak demo application printed text

vi ./pak-c-mak-demo-app/src/myholderclass.cpp

to something like that:

  #include<myholderclass.hpp>

  const char* MyHolderClass::GetHoldVariable() {
    return "MyHoldVariable of MyHolderClass updated text";
  };

Enabling pak-c-mak development mode, so package will be searched on local first.

export PAK_C_MAK_LOCAL_PACKAGES=*

Building and installing pak-c-mak demo application again

./pak-c-mak/pak-c-mak install pak-c-mak-demo-app
  Cloning into '/home/vagrant/pak-c-mak-test/pak-c-mak/pak_c_mak_tmp/downloads/packages/pak-c-mak-demo-app'...
  ...
  [100%] Built target pak_c_mak_demo_app_executable
  Install the project...
  -- Install configuration: ""
  -- Installing: /home/vagrant/pak-c-mak/cache/lib/libpak_c_mak_demo_app_library.a

Verifying that locally changed copy of pak-c-mak demo application is installed.

./pak-c-mak/cache/bin/pak_c_mak_demo_app_executable
  MyHoldVariable of MyHolderClass updated text

Creating pak-c-mak repository

To create your pak-c-mak repository, just simply use pak-c-mak-demo-repo as template for your repository.

Build using CMake CMAKE_PREFIX_PATH

To access artifacts installed into pak-c-mak cache, CMAKE_PREFIX_PATH variable could be used for CMake based modules. More information about this variable can be found in CMake official documentation.

https://cmake.org/cmake/help/latest/variable/CMAKE_PREFIX_PATH.html

To configure CMAKE_PREFIX_PATH variable for using pak-c-mak cache, please use following command:

source ./pak-c-mak/pak-c-mak-env

Cleaning CMake build cache

Some changes to CMakeLists.txt file may require cleaning of cmake build cache, please use following command:

./pak-c-mak/pak-c-mak clean-cmake-build

Contribution

If you would like to contribute - any help would be appreciated:

• The platform currently was not tested on OS X and BSD platform, so looking for feedbacks.
• If you've found this tool useful and you are keeping pak-c-mak repositories with your modules, please let know, will keep DB updated with list of public pak-c-mak repositories.
• Project team is open for any suggestions and improvements.

Contacts

For any question feel free to contact me: Dmytro Brazhnyk <[email protected]>