lastversion 0.2.2

A CLI tool to fetch last GitHub release version

lastversion

A tiny command line utility that helps to answer one simple question:

What is the latest released version for a GitHub project?

GitHub has an API endpoint here. But if you're here, then you know how it sucks:

A release would show up in this API response only if it was filed formally using GitHub release interface. Sometimes project authors use formal releases, and next thing you know, for next release they won't. There is no consistency in human beings.

OK, you think you could use another API endpoint to list tags. Tags usually represent a release, however, the API does not sort them chronologically. Moreover, you might get something like "latest-stable" for a tag name's value.

In general, quite many project authors complicate things further by:

• Creating a formal release that is clearly a Release Candidate (rc in tag), but forget to mark it as a pre-release
• Putting extraneous text in release tag e.g. release-1.2.3 or name-1.2.3-2019 anything fancy like that
• Putting or not put a 'v' prefix to release tags. Today yes, tomorrow not. I'm not consistent about it myself :)
• Switching from one version format to another, e.g. v20150121 to v2.0.1

To deal with all this mess and simply get well-formatted, last stable version (or download URL!) on the command line, you can use lastversion.

Its primary use is for build systems - whenever you want to watch specific repositories for released versions in order to build packages automatically. Or otherwise require getting latest version in your automation scripts.

Like I do

lastversion does a little bit of AI in order to detect if releasers mistakenly filed beta version as a stable release. It uses both of the API endpoints and incorporates logic for cleaning up human inconsistency from version information.

Synopsis

lastversion apache/incubator-pagespeed-ngx #> 1.13.35.2

Download latest version of something

You can also use lastversion to get assets/source download URLs for the latest release.

wget $(lastversion --assets mautic/mautic)

This will download all assets of the newest stable Mautic, which are 2 zip files.

How this works: lastversion outputs all asset URLs, each on new line, and wget is smart enough to download each URL. Magic :)

For releases which have no assets added, it will download source archive.

To always download source, use --source instead:

wget $(lastversion --source mautic/mautic)  

An asset is a downloadable file that typically represents an executable, or otherwise "ready to launch" project. It's what you see filed under formal releases, and is usually a compiled (for specific platform), program.

Source files, are either tarballs or zipballs of sources for the source code of release.

Get last version (betas are fine)

We consider latest release is the one which is stable / not marked as beta. If you think otherwise, then pass --pre switch and if the latest version of repository is a pre-release, then you'll get its version instead:

lastversion --pre mautic/mautic #> 2.15.2b0

Usage

Typically, you would just pass a repository URL (or repo owner/name to it) as the only argument, e.g.:

lastversion https://github.com/gperftools/gperftools

Equivalently accepted invocation with same output is:

lastversion gperftools/gperftools    

If you're lazy to even copy paste a project's URL, you can just type its name as argument, which will use repository search API (slower). Helps to answer what is the latest Linux version:

lastversion linux     

Or wondering what is the latest version of Wordpress? :

lastversion wordpress

A special value of self for the main argument, will lookup the last release of lastversion itself.

For more options to control output or behavior, see --help output:

usage: lastversion [-h] [--pre] [--verbose]
                  [--format {version,assets,source,json}] [--assets]
                  [--source] [--version] [-gt VER] [--filter REGEX]
                  REPO

Get latest release from GitHub.

positional arguments:
 REPO                  GitHub repository in format owner/name

optional arguments:
 -h, --help            show this help message and exit
 --pre                 Include pre-releases in potential versions
 --verbose
 --format {version,assets,source,json}
                       Output format
 --assets              Returns assets download URLs for last release
 --source              Returns only source URL for last release
 --version             show program's version number and exit
 -gt VER, --newer-than VER
                       Output only if last version is newer than given
                       version
 --filter REGEX        Filters --assets result by a regular expression

The --format will affect what kind of information from last release and in which format will be displayed, e.g.:

• version is the default. Just outputs well format version number
• assets will output newline separated list of assets URLs (if any), otherwise link to sources archive
• source will output link to source archive, no matter if the release has some assets added
• json can be used by external Python modules or for debugging, it is JSON output of an API call that satisfied last version checks

You can use shortcuts --source instead of --format source, and --assets instead of --format assets, as in the above examples.

lastversion --source mautic/mautic #> https://github.com/mautic/mautic/archive/2.15.1/mautic-2.15.1.tar.gz

By default, lastversion filters output of --assets to be OS specific. Who needs .exe on Linux?

To override this behavior, you can use --filter, which has a regular expression as its argument. To disable OS filtering, use --filter ., this will match everything.

You can naturally use --filter in place where you would use grep, e.g. lastversion --assets --filter win REPO

Scripting with lastversion

Check for NEW release

When you're building some upstream package, and you did this before, there is known "last build| version. Automatinc builds become easy with:

CURRENTLY_BUILT_VER=1.2.3 # stored somewhere, e.g. spec file in my case
LASTVER=$(lastversion repo/owner -gt $CURRENTLY_BUILT_VER)
if [ $? -eq 0 ]; then
  # LASTVER is newer, update and trigger build
  ....

Status codes

Exit status codes are the usual means of communicating a command's execution success or failure. So lastversion follows this: successful command returns 0 while anything else is an error of some kind:

Exit status code 1 is returned for cases like no release tag existing for repository at all, or repository does not exist.

Exit status code 2 is returned for -gt version comparison negative lookup.

Exit status code 3 is returned when filtering assets of last release yields empty URL set (no match)

Installation for CentOS 7

yum install https://extras.getpagespeed.com/release-el7-latest.rpm
yum install lastversion

Packaged install relies on some dependencies that were missing in EPEL or base repository. Following dependent packages are in our repository as well:

• python2-CacheControl
• newer python2-msgpack

Installation for other systems

The script is primarily developed for Python 2.7, but is known to work with recent versions like Python 3.7. Installing with pip is easiest:

pip install lastversion

Tips

Getting latest version is heavy on the API, because GitHub does not allow to fetch tags in chronological order, and some repositories switch from one version format to another, so we can't just consider highest version to be latest. We have to fetch every tag's commit date, and see if it's actually more recent. Thus it's slower with larger repositories, which have potentially a lot of tags.

Thus, lastversion makes use of caching API response to be fast and light on GitHub API, It does conditional ETag validation, which, as per GitHub API will not count towards rate limit. The cache is stored in ~/.cache/lastversion on Linux systems.

It is much recommended to setup your GitHub API token in ~/.bashrc like this, to increase your rate limit:

export GITHUB_API_TOKEN=xxxxxxxxxxxxxxx

Then run source ~/.bashrc. After this, lastversion will use it to get larger API calls allowance from GitHub.

Usage in a Python module

from lastversion import lastversion
repo = "mautic/mautic"
lastVersion = lastversion.latest(repo, 'version', True)
print(lastVersion)

Will yield: 2.15.2b0.

The lastversion.latest function accepts 3 arguments

• repo, in format of <owner>/<name>, or any URL under this repository, e.g. https://github.com/dvershinin/lastversion/issues
• format, which accepts same values as when you run lastversion interactively
• preOk, boolean for whether to include pre-releases as potential versions

Check if there is a newer kernel for your Linux machine

NEWER_KERNEL=$(lastversion linux -gt $(uname -r | cut -d '-' -f 1))
if [ $? -eq 0 ]; then
  echo "I better update my kernel now, because ${KERNEL} is there"
else 
  echo "My kernel is latest and greatest."
fi