I am trying to build a wrapper around some docker-compose functionality to make it easier for other to move into the new repo (previous repos used make files for running the commands). I have a file like this:

"""Quick commands for running docker-compose environment."""
from typing import Iterable

from pants.base.build_root import BuildRoot
from pants.core.util_rules.system_binaries import BinaryPathRequest, BinaryPaths
from pants.engine.console import Console
from pants.engine.fs import Digest, PathGlobs, Paths
from pants.engine.goal import Goal, GoalSubsystem
from pants.engine.process import Process, ProcessResult
from pants.engine.rules import Get, Rule, collect_rules, goal_rule
from pants.option.option_types import BoolOption, StrOption


class DockerComposeSubsystem(GoalSubsystem):
    """Run docker compose commands."""

    name = "docker-compose"
    help = "Run docker-compose commands"

    command = StrOption(default="", help="Command to run")
    up = BoolOption(default=False, help="Spin up docker environment in background")
    up_fg = BoolOption(default=False, help="Spin up docker environment in foreground")
    down = BoolOption(default=False, help="Spin down docker environment")
    ps = BoolOption(default=False, help="List running processes")


class DockerComposeGoal(Goal):
    """Result of running commands."""

    subsystem_cls = DockerComposeSubsystem


@goal_rule
async def docker_compose(
    console: Console, buildroot: BuildRoot, subsystem: DockerComposeSubsystem
) -> DockerComposeGoal:
    docker_compose_paths = await Get(
        BinaryPaths,
        BinaryPathRequest(
            binary_name="docker-compose", search_path=["/usr/bin", "/bin", "/usr/local/bin"]
        ),
    )
    docker_compose_bin = docker_compose_paths.first_path
    if docker_compose_bin is None:
        raise OSError("Could not find 'docker-compose'.")
    paths = await Get(Paths, PathGlobs(["docker-compose/*.yml"]))
    command_additions = [
        paths.files[idx // 2] if idx % 2 == 1 else "-f" for idx in range(len(paths.files) * 2)
    ]
    digest = await Get(Digest, PathGlobs(["docker-compose/*.yml"]))
    if subsystem.up:
        await Get(
            ProcessResult,
            Process(
                argv=[docker_compose_bin] + command_additions + ["up", "-d"],
                description="Spin up docker-compose in background",
                input_digest=digest,
            ),
        )
    elif subsystem.down:
        await Get(
            ProcessResult,
            Process(
                argv=[docker_compose_bin] + command_additions + ["down"],
                description="Spin down docker-compose",
                input_digest=digest,
            ),
        )
    elif <http://subsystem.ps|subsystem.ps>:
        await Get(
            ProcessResult,
            Process(
                argv=[docker_compose_bin] + command_additions + ["ps"],
                description="List docker-compose running environment",
                input_digest=digest,
            ),
        )
    return DockerComposeGoal(exit_code=0)


def rules() -> Iterable[Rule]:
    return collect_rules()

However, when I try to run this, I get errors that the filesystem changed during the run. I am trying to understand how to prevent that

is there anything in

.pants.d/pants.log

? i expect that you have a type error in the

Process

constructor. that’s no longer fatal on

main

, but has been in past releases.

Briliant, caught that the docker_compose_bin needs to be docker_compose_bin.path. Onto the second thing. Looks like it docker-compose needs to have the docker command also available in the path. Is that down by merging a digest with that?

by default

Process

is very isolated and sandboxed

Okay, Will try that. Thanks

InteractiveProcess

uses the entire env by default, so it shouldn’t be necessary to expand it explicitly