How do I get the latest tag value from the github API for a given repository

Question

I can get the latest commit from the GitHub api using :

$ curl 'https://api.github.com/repos/dwkns/test/commits?per_page=1'

However the resulting JSON doesn't contain any reference to the tag I created when I did that commit.

I can get a list of tags using :

$ curl 'https://api.github.com/repos/dwkns/test/tags'

However the resulting JSON, while it contains the names of tags I want, is not in the order in which they were created - there is no way of telling which tag is the latest one.

EDIT : The latest tag created was LatestLatestLatest

My question then is what API call(s) do I need to do to get the name of the latest tag in my repository?

Answer 1

Using jq in combination with curl you can have a pretty straightforward command:

curl -s \
  -H "Accept: application/vnd.github.v3+json" \
  https://api.github.com/repos/dwkns/test/tags \
  | jq -r '.[0].name' 

Output (as of today):

v56

Explanation on jq command:

• -r is for "raw", avoid json quotes on jq's output
• .[0] selects the first (latest) tag object in json array we got from github
• .name selects the name property in this lastest json object

Answer 2

#!/bin/sh
curl -s https://github.com/dwkns/test/tags |
awk '/tag-name/{print $3;exit}' FS='[<>]'

Or

#!/bin/awk -f    
BEGIN {
  FS = "[<>]"
  while ("curl -s https://github.com/dwkns/test/tags" | getline) {
    if(/tag-name/){print $3;exit}
  }
}

Answer 3

Semantic Versioning Example

NOTE: If you're in a hurry and don't need all the fine details explained, just jump down to " The Solution " and execute the command.

This solution uses curl and grep to match the LATEST semantically versioned release number. An example will be demonstrated using my own Github repo " pi-ap " (a pile of bash scripts which automates config of a Raspberry Pi into a wireless AP).

You can test the example I give you on the CLI and after you're satisfied it works as intended, you can tweak it to your own use-case.

Versioning Format Construction:

Since we're using grep to match the version number, I need to explain its' construction. 3 pairs of integers separated by 2 dots and prefaced by a "v":

vXX.XX.XX
 ^  ^  ^
 |  |  |
 |  |  Patch
 |  Minor
 Major

NOTE: If a field only has a single digit, I'll pad it with a zero to ensure the resulting format is predictable: always 3 pairs of integers separated by 2 dots.

The Solution:

Github Username: F1Linux
Github Repo Name: pi-ap (NOTE: exclude the " .git " suffix)

curl -s 'https://github.com/f1linux/pi-ap/tags/'|grep -Eo "$Version v[0-9]{1,2}.[0-9]{1,2}.[0-9]{1,2}"|sort -r|head -n1

Validate the Result Correct:

In your browser, go to:

https://github.com/f1linux/pi-ap/tags

And validate that the latest tag was returned from the command.

The above is fairly extensible for most use-cases. Just need to change the user & repo names and remove/replace the "v" if you don't use this convention in tagging your repos.