[andrewpark-scaleai]

Why

The goal is faster agentenv-framework CI with no test weakened. Each Docker shard runs mirror_base_images.py, which pulls its 9 base images one after another. In CI that takes 25s, and the slowest single pull takes 5s. It runs on every Docker shard, including the slow tier's longest.

What

• mirror_base_images.py pulls all the bases at the same time. It still switches dockerd to the containerd store first, and each image keeps its own retries and tag.
• test_the_bases_are_pulled_at_once holds both fake pulls at a barrier. It fails on main's serial code (BrokenBarrierError) and passes with this change.

Expected effect

About 15s off every Docker shard. That's an estimate from the CI step times. This PR's own run will show the measured time.

Verification

• tst/unit/test_mirror_base_images_script.py passes, 10 tests.
• An independent review found no defects.

Confidence Score: 5/5

The PR appears safe to merge; no actionable issues were found.

Summary

mirror_base_images.py now pulls base images concurrently.

• CI jobs pull Docker base images together before their builds.

_{Reviews (1) · Last reviewed commit: "ci: pull the base images from mirror.gcr..." · Reviewed by Greptile}