dockerize.py

#!/usr/bin/env python
# Copyright (C) 2019 Woods Hole Oceanographic Institution
#
# This file is part of the CGSN Mooring Project ("cgsn-mooring").
#
# cgsn-mooring is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 2 of the License, or
# (at your option) any later version.
#
# cgsn-mooring is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with cgsn-mooring in the COPYING.md file at the project root.
# If not, see <http://www.gnu.org/licenses/>.
'''
This tool can be used to execute a command or start an interactive session in an
environment similar to that used by continuous integration builds.

Without a command, an interactive shell is started:
    scripts/dockerize.py --job amd64-bionic-build

With a command, the command is executed in the environment:
    scripts/dockerize.py --job amd64-bionic-build uname -a

To perform a full build in a local CircleCI-like environment, instead use:
    circleci local execute --job amd64-bionic-build
'''

from __future__ import print_function

import argparse
import os
import pipes
import subprocess
import sys

try:
  import yaml
except ImportError:
  print('Error: Please install PyYAML', file=sys.stderr)
  print('    pip install pyyaml', file=sys.stderr)
  print('    apt-get install python-yaml', file=sys.stderr)
  raise


# Parse command-line arguments
parser = argparse.ArgumentParser(description=__doc__,
  formatter_class=argparse.RawDescriptionHelpFormatter)
parser.add_argument('--show-jobs', action='store_true',
  help='list out jobs defined in the CircleCI config')
parser.add_argument('--job', default='amd64-bionic-build',
  help='the job environment to use from the CircleCI config')
parser.add_argument('--dry-run', action='store_true',
  help='display commands to be run without executing them')
parser.add_argument('command', nargs=argparse.REMAINDER,
  help='the command to execute in the container (default: /bin/bash)')
args = parser.parse_args()

if not args.command:  # parser.add_argument(default=...) didn't work
  args.command = [ '/bin/bash' ]

if len(args.command) > 0 and args.command[0] == '--':
  del args.command[0]  # drop the -- separator if it was captured


# Path calculations
repo_path = subprocess.check_output(['git', 'rev-parse', '--show-toplevel'],
  cwd=os.path.dirname(__file__)).rstrip()
mapped_path = os.path.join('/root', os.path.basename(repo_path))
config_path = os.path.join(repo_path, '.circleci', 'config.yml')


# Make sure prerequisites are installed
try:
  subprocess.check_call(['circleci', 'version'], stdout=open(os.devnull, 'wb'))
except:
  print('Error: Please install the CircleCI command line tool', file=sys.stderr)
  print('    https://circleci.com/docs/2.0/local-cli', file=sys.stderr)
  sys.exit(1)

try:
  subprocess.check_call(['docker', 'version'], stdout=open(os.devnull, 'wb'))
except:
  print('Error: Please install Docker', file=sys.stderr)
  print('    https://docs.docker.com/install/', file=sys.stderr)
  sys.exit(1)


# Canonicalize and read the configuration file
config_yaml = subprocess.check_output(['circleci', 'config', 'process',
  '--skip-update-check', config_path])
config = yaml.load(config_yaml)


# Display a list of jobs (--show-jobs)
if args.show_jobs:
  if sys.stdout.isatty():
    print('The following jobs are configured in the CircleCI config:')
    for job in config['jobs'].keys():
      print('  *', job)
  else:
    for job in config['jobs'].keys():
      print(job)
  sys.exit(0)


# Awkwardly parse out settings we care about
try:
  job = config['jobs'][args.job]
except:
  print('Error: job', args.job, 'not found in CircleCI config', file=sys.stderr)
  sys.exit(1)

image = next(x['image'] for x in job['docker']
  if isinstance(x, dict) and 'image' in x)
env_vars = { k: v for d in job.get('environment', []) for k, v in d.items() }

if 'working_directory' in job:
  mapped_path = job['working_directory']


# Parse (poorly) any environment variables out of the command as well
for i, arg in enumerate(args.command):
  k, eq, v = arg.partition('=')
  if eq == '':  # first non-variable, does not contain =
    del args.command[:i]
    break
  env_vars[k] = v


# Build the command
command = [
  'docker', 'run',
  '--cap-add', 'SYS_PTRACE',  # allow using GDB in the container
  '--volume', repo_path + ':' + mapped_path,  # map this repo into the container
  '--workdir', mapped_path,  # set current working directory
  '--interactive',
  '--tty',
]

for k, v in env_vars.items():
  command += ['--env', k + '=' + v]

command.append('--')
command.append(image)
command += args.command


# Run (or print) the command
if args.dry_run:
  print(' '.join(pipes.quote(x) for x in command))
else:
  os.execvp(command[0], command)