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This repository contains a new approach to Erlang/Elixir package creation and publishing.

The packaging repo consists of three distinct pieces: building from source, packaging and publishing.

Requirements

  • nproc (coreutils)
  • jq

Building Erlang / Elixir

We wish to build any version of Erlang or Elixir for a variety of different operating systems and hardware architectures. Collectively the Makefile and Dockerfile_* files constitute this new build system. The Makefile is parameterized, allowing run-time selection of all these things. By default, nothing is built. You must set the ERLANG_VERSIONS, ELIXIR_VERSIONS, DEBIAN_VERSIONS, UBUNTU_VERSIONS, CENTOS_VERSIONS and PLATFORMS parameters.

The build system uses Docker and in particular the buildx enhancements. Docker is configured for multi-arch support. The main.tf and cloud-init.yaml file instantiates an appropriate AWS instance, installs Docker, and configures it for multi-arch builds.

The Dockerfile_* files perform the entire build process, from installing the build dependencies, testing, signing and finally outputting a package. These files have some conditional elements to account for differences across the currently supported range of versions of Debian/Ubuntu/CentOS in a way that is hopefully a guide for any additional future nuances.

In order to improve build times, especially if a previous build has been run (or partially run), the docker scripts use the buildx "mount cache" feature, ensuring we cache any dependencies that we need to downloaded. Foreign architecture builds are built with a cross-compiler where available (Debian and Ubuntu).

The docker files are ordered such that as much work as possible is done before the version-specific build begins, so that the docker cache can be leveraged when building multiple erlang versions for the same operating system targets.

Finally, the OTP smoke test must run successfully for an artifact to be produced. Same pattern is applied for mongooseim and elixir.

Package Generation

The build scripts (Dockerfile_*) use fpm to generate packages. This change radically simplifies the process of package generation.

Single erlang package example

If you check the makefile you will see the different parameters used in making a single erlang package. Let us say that you would like to build Erlang 24.2.2 for rockylinux 8 targeting linux/am64.

make  erlang_24.2.2_rockylinux_8_rockylinux_linux-amd64

Implementing a new builder

There is no need to implement a new builder according to the current packages that are listed in the ESL website. The builders folder contains two main Dockerfiles per package to build that behave as the entry point for both main distros, centos and debian. Like so:

.
├── elixir_debian.Dockerfile
├── elixir_fedora.Dockerfile ⇒ elixir_centos.Dockerfile
...
├── erlang_centos.Dockerfile
├── erlang_rockylinux.Dockerfile ⇒ erlang_centos.Dockerfile
...
├── mongooseim_debian.Dockerfile
└── mongooseim_ubuntu.Dockerfile ⇒ mongooseim_debian.Dockerfile
...

The others are just symbolic links. Meaning that if we want to implement a new builder a first good step would be to copy the main centos or debian Dockerfiles and rename them accordingly.

Publishing

For CentOS releases it is still the best approach to continue using createrepo and so there is no additional work in this repo. createrepo is appropriate because it includes the digest of each index file in the filename. This is important due to the CloudFront caching we apply in front of our package repository and is the reason the "corruption" issue that the Debian and Ubuntu packages currently face does not occur there.

Debian/Ubuntu repositories have traditionally suffered from a number of race conditions that render them temporarily corrupt. This surfaces during normal Debian mirroring but also with our custom scripting in packages-pipeline.

There are two fundamental issues, both of which are significantly compounded by the 24 hour CloudFront caching policy we add on top.

Firstly, the top-level Release file and its signature in Release.gpg. A client must see a consistent set of these files, or else it will (correctly) conclude that the signature is not valid. This is addressed by the InRelease file which apt-get attempts to fetch first. Our current scripts do not generate it but the new approach will. The InRelease file is a cleartext-signed version of the Release file, so the signature can always be successfully verified.

Secondly, the Release file contains the checksums of the Packages* files, so a client that sees a new Release file but a cached Packages file can also conclude that our repository is corrupt. This is addressed by the Acquire-By-Hash feature, in much the same way as createrepo does for CentOS.

We could enhance our current scripting to do these two things but rather than do that I think it is better to adopt a high level tool.

I have chosen Aptly for this work.

Deploying to Production

Finally the new site is here. As of , we will be transitioning away from the old packages system, but fear not! The legacy packages will remain accessible at on packages.erlang-solutions.com and archives.erlang-solutions.com for your convenience. And to avoid issues with current pipelines or workflows.

Installation Instructions

Add the Erlang Solutions public key for "apt-secure" using following commands::

wget https://binaries2.erlang-solutions.com/GPG-KEY-pmanager.asc\nsudo apt-key add GPG-KEY-pmanager.asc\n

To add Erlang Solutions repository (including our public key for apt-secure) to your system, call the following commands:

adding the repository entry manually Add one of the following lines to your /etc/apt/sources.list (according to your distribution):

deb http://binaries2.erlang-solutions.com/ubuntu/ jammy-esl-erlang-25 contrib

deb http://binaries2.erlang-solutions.com/debian/ bullseye-elixir-1.15 contrib

deb http://binaries2.erlang-solutions.com/ubuntu/ bionic-mongooseim-6 contrib

Contributing

Review Contribution Guidelines

TO-DO

  • Create deb and rpm autoinstallable ESL sources
  • Bugfixing: Solve ARM64 issue
  • Stabilization of the new platform