elm-package install that works in Docker

elm-package-install.py

#!/usr/bin/env python2.7
import tempfile, os, sys, shutil, json
from subprocess import call

ELM_STUFF = 'elm-stuff'
DEPS_PATH = 'exact-dependencies.json'

def download_to(url, fileName):
    call('wget -O "{fileName}" "{url}"'.format(**locals()), shell=True)

def untargz_to(archive, dest_dir):
    call(
        'gzip -dc {0} | tar -xf - -C {1}'.format(os.path.abspath(archive), os.path.abspath(dest_dir)),
        shell=True)

def retry_on_fail(times, action):
    try:
        action()
    except Exception as e:
        if times > 0: return retry_on_fail(times - 1, action)
        else: raise

def install_single(package, version):
    print 'Installing {package}-{version}...'.format(**locals())

    # make sure elm-stuff exists
    if not os.path.exists(ELM_STUFF):
        os.makedirs(ELM_STUFF)

    # remove the installed package, if any
    pkg_dir = os.path.join(ELM_STUFF, "packages", package, version)
    if os.path.exists(pkg_dir):
        shutil.rmtree(pkg_dir)

    fd, tmpfile = tempfile.mkstemp()
    os.close(fd)
    tmpdir = tempfile.mkdtemp()

    try:
        tarball_url = 'http://github.com/{0}/archive/{1}.tar.gz'.format(package, version)

        print 'Downloading {}...'.format(tarball_url)
        retry_on_fail(10, lambda: download_to(tarball_url, tmpfile))

        print 'Unpacking...'
        untargz_to(tmpfile, tmpdir)

        print "Copying to %s" % (pkg_dir)
        # the tar.gz will consist of a single dir, named PROJECT-VERSION
        package_root = os.path.join(tmpdir, '{0}-{1}'.format(package.split('/')[1], version))
        shutil.copytree(package_root, pkg_dir)
    finally:
        os.remove(tmpfile)
        shutil.rmtree(tmpdir)

def install_packages(deps):
    print 'Will install following packages:'
    print '\n'.join(map(lambda x: '- ' + repr(x), deps.iteritems()))

    for pkg, ver in deps.iteritems():
        install_single(pkg, ver)

def write_exact_dependencies(deps):
    print 'Writing exact-dependencies.json...'
    with open(os.path.join(ELM_STUFF, 'exact-dependencies.json'), 'w') as f:
        json.dump(deps, f)

if __name__ == '__main__':
    with open(DEPS_PATH, 'r+') as f:
        deps = json.load(f)

    install_packages(deps)
    write_exact_dependencies(deps)

    print 'All done!'

elm-package-update

#!/bin/sh
# Run this every time you need to update dependencies. This will maintain the
# exact-dependencies.json file that is needed for docker build.
#
# We need this because elm-package install doesn't work in Docker, so we use
# this hacky script to install packages which doesn't implement transitive
# dependency resolution. So we feed it a list of already resolved exact
# dependencies.

elm-package install
cp elm-stuff/exact-dependencies.json exact-dependencies.json