Get the image tags for an AWS ECR repo that exist within a branch. Prints them to STDOUT in descending order of pushed date.

git_branch_commits_in_ecr_repo.py

"""
Use as:

    REPO='ecr-repo-name' BRANCH='main' python git_branch_commits_in_ecr_repo.py

You can pipe this to `cut -f1 -s` to get the commits only. Or `-f2` to get the pushed by date only.
These values are separated by a tab (`"\t"`).
"""
import json
import os
import subprocess
import tempfile
from datetime import datetime
from typing import List, NamedTuple


class DatedTag(NamedTuple):
    image_tag: str
    pushed_at: datetime


def ecr_tags_in_branch(repo: str, branch: str) -> List[DatedTag]:

    # get commits
    with tempfile.NamedTemporaryFile("wt") as tf:
        tf.write("#!/usr/bin/env bash\n")
        tf.write(
            "git log %s | grep --color=auto --exclude-dir={.bzr,CVS,.git,.hg,.svn,.idea,.tox} '^commit ' | cut -f2 -d' '\n"
            % branch
        )
        tf.flush()
        os.system(f"chmod +x {tf.name}")
        commits_b = subprocess.check_output([tf.name])
    commits: List[str] = [
        c.strip() for c in commits_b.decode("utf8").split("\n") if len(c.strip()) > 0
    ]

    # describe the ECR repository
    json_ecr_images = subprocess.check_output(
        (
            "aws",
            "ecr",
            "describe-images",
            f"--repository-name={repo}",
        )
    ).decode("utf8")

    # get the image tags that appear in the branch & get their push dates
    ecr_tag_in_master: List[DatedTag] = []
    image_details = json.loads(json_ecr_images)["imageDetails"]
    for imgd in image_details:
        pushed_date = datetime.fromisoformat(imgd["imagePushedAt"])
        for image_tag in imgd["imageTags"]:
            for c in commits:
                if c in image_tag:
                    ecr_tag_in_master.append(DatedTag(image_tag, pushed_date))

    # most recent pushed tags first
    ecr_tag_in_master.sort(key=lambda x: x[1], reverse=True)

    return ecr_tag_in_master


if __name__ == "__main__":
    try:
        repo = os.environ["REPO"]
    except KeyError:
        print("ERROR: need 'REPO' env var for ECR repository name")
        os.exit(1)
    branch = os.environ.get("BRANCH", "master")
    for c, d in ecr_tags_in_branch(repo, branch):
        print(f"{c}\t{d}")