Using "hare release" to ship Hare software November 22, 2021 by Drew DeVault

The “hare” command now includes a new sub-command, “hare release”, which can be used to manage releases for software written in Hare. This tool checks for common mistakes and establishes common packaging standards for use throughout the Hare ecosystem, making releases easy, consistent, and difficult to screw up. Let me explain how it works, and how to use it for your own releases.

First of all, this tool is totally optional. If you have a release process you already like, or your project’s release situation demands special attention, you can skip this tool entirely. But, if you choose to use it, you can ship the first version of your software by running hare release 1.0.0. If you want to ship a pre-release, something like hare release 0.0.1 may be more appropriate. The experience ends up being something like this:

This process automatically runs a number of sanity checks to avoid common mistakes, such as:

You may have also noticed that we prompted the user to generate a new SSH key. If you already have an SSH key, this step will be skipped. This SSH key is used to sign a generated .tar.gz file of the release, and store it in git as a “git note”, attached to the git tag. We chose to use SSH keys because they are more ubiquitous among contemporary developers than PGP, which is also more complex and difficult to use.

If you wish to verify this signature, create a “principals” file containing a list of all users who are allowed to sign releases, based on the contents of ~/.ssh/id_ed25519.pub (or whatever key is appropriate). In my case, I can create a file like this:

sir@cmpwn.com ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIKRe0pYxNubFS3VryJzuIH6qSW248SOo/rSFHDVs1Ux1

I’m using my git committer email here, as well as the contents of my public key file. I could also add several more keys, if there are multiple release managers on this project. I can publish this file on our project website, or in the git repository, or just let others write it themselves based on my automatically published SSH keys at meta.sr.ht/~sircmpwn.keys or github.com/ddevault.keys.

Once I have a principals file, I can extract the git note and compare it with the archive:

$ GIT_NOTES_REF=refs/notes/signatures/tar.gz git notes show 1.0.0 > /tmp/sig
$ git archive --format=tar.gz --prefix=example-project-1.0.0/ 1.0.0 \
  | ssh-keygen -Y verify -n file -s /tmp/sig -f ~/.ssh/principals -I sir@cmpwn.com
Good "file" signature for sir@cmpwn.com with ED25519 key SHA256:5TPjHnA7eOseMBFSxylGAwg9KaTdofMEM5jLZfF+xs8

This approach to creating tag signatures is natively supported by git.sr.ht, and I hope by other forges soon as well. When you push your tags, a link to download the corresponding signature will appear in the release notes.

Speaking of release notes, what happens when it’s time to release something other than the initial version? Hare encourages the use of semantic versioning, and the hare release tool provides automatic version increments for major, minor, and patch releases. In short:

hare release then uses git-shortlog(1) to pre-generate release notes for you. If you’ve been using good commit discipline, you might not have to edit them at all! Check it out:

In the future, we hope to be able to analyze the difference between versions and automatically detect if you have made breaking changes, and choose the appropriate version increment for you. A release might be as simple as running hare release with no arguments, glancing over the generated release notes, punching in your key’s password, and running git push --follow-tags to ship.

It is my hope that access to this tool will make it easier for Hare users to manage their releases in a consistent manner which behaves uniformly across the Hare ecosystem, creating a supply chain with a predictable approach and a culture of ubiquitous cryptographic signatures to verify the integrity of Hare software.

Today, this is based on git and SSH, which were selected in response to the dominant trends in software development. However, the command line interface is not tied down to these tool choices. I hope that proponents of other version control systems will help us generalize hare release to support their software, and to expand to support other approaches to signatures as well. In addition to providing a uniform approach to release management across the Hare ecosystem, we are positioned to ship upgrades which make improvements across the same wide breadth of software in our ecosystem. Per our steadfast commitment to stability and reliability, large changes along these lines will be scarce, but rest assured that we are not painted into a corner by choosing these tools.

I hope you find this tool useful for your projects! Check out the man pages if you want to learn more about the design and usage of hare release. Go forth and ship!