tools/hscloud/lib.py

# Library to interact with the active hscloud checkout. This supersedes the
# hscloud_root environment variable once used in hscloud.
#
# Some of this could be implemented in Python instead of shelling out to a Go
# binary - but that way we have a single source of truth, even if it's janky.
#
# To use:
#
#    from tools.hscloud import lib as hscloud
#
# And specify deps = [ "//tools/hscloud:python" ] in py_binary.

import subprocess

from rules_python.python.runfiles import runfiles


r = runfiles.Create()


def tool_location():
    """
    Return an absolute path to a built //tools/hscloud binary, ready to run.
    """
    rloc = r.Rlocation("hscloud/tools/hscloud/hscloud_/hscloud")
    if rloc is None:
        raise Exception("Could not find location of hscloud - are you in a valid checkout?")
    return rloc.strip()


def workspace_location():
    """Return an absolute path to the hscloud checkout."""
    return subprocess.check_output([tool_location(), "workspace"]).decode().strip()


def must_rlocation(runfile):
    """Return an absolute path to a runfile, eg. a data depndency in sh_binary."""
    rloc = r.Rlocation(runfile)
    if rloc is None:
        msg = f"Could not find runfile {runfile}"
        manifest = os.environ.get("RUNFILES_MANIFEST_FILE", "")
        if manifest != "":
            msg += f"; manifest file: {manifest}"
        raise Exception(msg)
    return rloc.strip()