I m looking at speeding up our Docker image builds with Pant Pants #general

I'm looking at speeding up our Docker image builds...

elegant-art-7479

06/03/2025, 8:53 AM

I'm looking at speeding up our Docker image builds with Pants, and as the first idea I'd like to experiment with remote caching. I started a Bazel remote cache locally, added the below piece to my

pants.toml

under

[GLOBAL]

Copy code

remote_cache_read = true
remote_cache_write = true
remote_store_address = "<grpc://localhost:9092>"
remote_instance_name = "main"

and: 1. I see no difference in how Pants works. 2. The directory mounted to the cache's running container doesn't have any actual files, just some indices. What am I doing wrong? How can I debug it?

elegant-art-7479

06/03/2025, 9:29 AM

oh, I guess just Docker layer cache (not Pants' cache) works for the Docker backend, see https://pantsbuild.slack.com/archives/C046T6T9U/p1744210991104779

elegant-art-7479

06/03/2025, 9:34 AM

on a related topic (talking about caching), I started wondering on the point of using

{pants.hash}

in an image's tag. How can I get the hash without actually building an image, so that I can fetch a desired image?

elegant-art-7479

06/03/2025, 9:40 AM

I see

pants.hash

is calculated only in

DockerBuildContext

here: https://github.com/pantsbuild/pants/blob/5bb87c7b88c3e008ced9c48d0b806f95bb96b6f0/src/python/pants/backend/docker/util_rules/docker_build_context.py#L150

elegant-art-7479

06/03/2025, 9:41 AM

so if we build images with a command like

pants package foo/bar:baz

, I'd expect a flag to this command that would return just the hash. Or is there another intended use of

pants.hash

I'm not seeing?

elegant-art-7479

06/03/2025, 9:42 AM

(sorry for mixing up two topics in this thread, however the goal is the same: caching of Docker images, this way or another)

breezy-wolf-83149

06/07/2025, 3:42 PM

Created https://github.com/pantsbuild/pants/issues/22390

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