juju-dhx

#!/usr/bin/env python

import re
import os
import sys
import yaml
import subprocess
import itertools
from optparse import OptionParser

import jujuclient
import jujuclient.juju1.environment
import jujuclient.juju2.environment


JUJU_HOME = os.environ.get('JUJU_HOME', '')
CONFIG_FILE = os.path.join(JUJU_HOME, 'dhx-rc.yaml')
ALT_CONFIG_FILE = os.path.join(JUJU_HOME, 'debug-hooks-rc.yaml')
DEFAULT_CONFIG = {'import_ids': [],
                  'uploads': {},
                  'init': os.path.join(JUJU_HOME, 'debug-hooks-rc.d'),
                  'use_tmux_bindings': False,
                  'auto_sync': False,
                  'auto_restart': False,
                  'sync_exclude': ['*.pyc', '.*']}


def call(*args):
    try:
        return subprocess.check_output(('/usr/bin/env',) + args,
                                       stderr=subprocess.STDOUT)
    except subprocess.CalledProcessError as e:
        sys.stderr.write(e.output)
        sys.exit(e.returncode)


JUJU_ENV = call('juju', 'switch').rstrip('\n')
JUJU_VERSION = call('juju', 'version')
JUJU_2 = JUJU_VERSION.startswith('2.')


class CaseInsensitiveDict(dict):
    def __init__(self, *args, **kwargs):
        super(CaseInsensitiveDict, self).__init__(*args, **kwargs)
        for key in self.keys():
            if isinstance(self[key], dict):
                self[key] = CaseInsensitiveDict(self[key])

    def __getitem__(self, key):
        if key.lower() in self:
            key = key.lower()
        return super(CaseInsensitiveDict, self).__getitem__(key)

    def get(self, key, default=None):
        if key.lower() in self:
            key = key.lower()
        return super(CaseInsensitiveDict, self).get(key, default)


def show_help(option, opt, value, parser):
    print 'usage: juju dhx [options] [<unit-or-service>]'
    print 'purpose: Enhanced interactive remote hook debugging session, using tmux'
    print
    print 'options:'
    print '-c, --config (= "$JUJU_HOME/dhx-rc.yaml")'
    print '    yaml file to use for customizing the debug-hooks environment'
    print '-e, --environment (= current)'
    print '    juju environment to operate in'
    print '-i, --import-id AUTH_ID'
    print '    import an auth key for a shared debug session from Launchpad (you'
    print '    can also add IDs to the config file if you have some that you always'
    print '    want to import)'
    print '-j, --join'
    print '    join an existing remove debug session (useful for paired debugging)'
    print '    does not use the Juju identity, so one of your ssh identities'
    print '    must have been imported (e.g., with import_ids, below)'
    print '    note that your customizations will not be made to joined sessions'
    print '-r, --retry, --restart'
    print '    restart the failed hook, such that the session can debug it'
    print '-R, --no-retry, --no-restart'
    print '    do not restart the failed hook, even if auto_restart is true or'
    print '    --restart is given'
    print '-s, --sync'
    print '    sync changes to the charm from the remote unit back locally'
    print '    this ensures that changes made while debugging the charm'
    print '    are preserved'
    print '-S, --no-sync'
    print '    do not sync changes, even if auto_sync is true or --sync is given'
    print
    print 'config file options:'
    print 'use_tmux_bindings'
    print '    create an empty .tmux.conf to reset tmux to its default key bindings'
    print '    instead of using the screen bindings (note: this option has no effect'
    print '    if a custom .tmux.conf file is created via the uploads or init options)'
    print 'init'
    print '    file or directory name containing script(s) to be run once to setup'
    print '    a new machine; will create or append to a .bashrc file on the machine'
    print 'uploads'
    print '    a list of (or map of local to remote) files or directories to upload'
    print '    to the remote machine (this is only done once, and requires rsync)'
    print 'import_ids'
    print '    list of Launchpad user IDs to import into Juju to give access to'
    print '    the remote debugging session (they should then use --join)'
    print 'auto_restart'
    print '    always assume the --restart option'
    print 'auto_sync'
    print '    always assume the --sync option'
    print 'sync_exclude'
    print '    list of file patterns for --sync to exclude (see rysnc --exclude)'
    print
    print 'Note that the init script(s) will be run once, the first time the machine'
    print 'is connected to.  If you wish to have setup that runs each time, you will'
    print 'need to replace or append to the .bashrc file.  Also note that the init'
    print 'script(s) will block the login process, so if you have setup tasks that'
    print 'take a while to run, such as installing packages, you may want to run'
    print 'them in the background.'
    sys.exit()


def show_desc(option, opt, value, parser):
    if os.path.basename(__file__) == 'juju-debug-hooks-ext':
        print 'Alias for juju-dhx'
    else:
        print 'Enhanced interactive remote hook debugging session, using tmux'
    sys.exit(0)


def parse_args():
    parser = OptionParser(add_help_option=False)
    parser.add_option('-c', '--config', dest='config_file', default=None)
    parser.add_option('-e', '--environment', dest='env', default=JUJU_ENV)
    parser.add_option('-i', '--import-id', dest='import_ids', action='append', default=[])
    parser.add_option('-j', '--join', dest='join', action='store_true')
    parser.add_option('-r', '--retry', '--restart', dest='restart', action='store_true')
    parser.add_option('-R', '--no-retry', '--no-restart', dest='no_restart', action='store_true')
    parser.add_option('-s', '--sync', dest='sync', action='store_true')
    parser.add_option('-S', '--no-sync', dest='no_sync', action='store_true')
    parser.add_option('-h', '--help', action='callback', callback=show_help)
    parser.add_option('-d', '--description', action='callback', callback=show_desc)
    opts = parser.parse_args()
    parser.values.config_file = find_config_file(parser.values.config_file)
    return opts


def find_config_file(config_file):
    if config_file is not None:
        config_file = os.path.expanduser(config_file)
        if os.path.exists(config_file):
            return config_file
    else:
        if os.path.exists(CONFIG_FILE):
            return CONFIG_FILE
        elif os.path.exists(ALT_CONFIG_FILE):
            return ALT_CONFIG_FILE
    return None


def customize(unit_name, unit, opts):
    config = dict(DEFAULT_CONFIG)
    if opts.config_file:
        with open(opts.config_file) as fp:
            config = yaml.load(fp)
    import_ids = config.get('import_ids', []) + opts.import_ids
    do_import_ids(unit, import_ids, opts)
    if check_customized(unit_name, unit, opts):
        return config
    sys.stdout.write('Customizing machine...')
    sys.stdout.flush()
    uploads = config.get('uploads', {})
    if isinstance(uploads, (list, tuple)):
        uploads = {u: '' for u in uploads}
    for local, remote in uploads.iteritems():
        upload(unit_name, local, remote)
    if os.path.exists(os.path.expanduser(config.get('init', ''))):
        upload(unit_name, config['init'], '')
    upload(unit_name, os.path.join(os.path.dirname(__file__), 'dhx-init.sh'),
           '.dhx.init')
    call('juju', 'ssh', unit_name,
         'echo "DHX_USER_INIT=\'%s\' ./.dhx.init" >> .bashrc'
         % os.path.basename(config.get('init', '')))
    if config.get('use_tmux_bindings', False):
        call('juju', 'ssh', unit_name, 'sudo touch .tmux.conf')
    print 'done.'
    set_customized(unit_name, unit, opts)
    return config


def check_customized(unit_name, unit, opts):
    env = get_env(opts)
    machine = unit.get('Machine')
    annotations = env.get_annotation(machine, 'machine')['Annotations'] or {}
    return 'dhx-customized' in annotations


def set_customized(unit_name, unit, opts):
    env = get_env(opts)
    machine = unit.get('Machine')
    env.set_annotation(machine, 'machine', {'dhx-customized': 'true'})


def do_import_ids(unit, import_ids, opts):
    if not import_ids:
        return
    env = get_env(opts)
    machine = unit.get('Machine')
    annotations = env.get_annotation(machine, 'machine')['Annotations'] or {}
    import_ids = ['lp:{}'.format(iid) if ':' not in iid else iid
                  for iid in import_ids]
    if annotations.get('import-ids') != ','.join(import_ids):
        cmd = ['juju']
        if JUJU_2:
            cmd.append('import-ssh-key')
        else:
            cmd.extend(['authorized-keys', 'import'])
        cmd.extend(import_ids)
        call(*cmd)
        env.set_annotation(machine, 'machine', {'import-ids': ','.join(import_ids)})


def get_env(opts):
    if hasattr(get_env, '_env'):
        return get_env._env
    if JUJU_2:
        get_env._env = jujuclient.juju2.environment.Environment.connect(opts.env)
    else:
        get_env._env = jujuclient.juju1.environment.Environment.connect(opts.env)
    return get_env._env


def _unit_errored(unit):
    if JUJU_2:
        return unit['workload-status']['status'] == 'error'
    else:
        return unit['AgentState'] == 'error'


def find_errored_unit(units):
    if not units:
        return None
    for name, unit in units.items():
        if _unit_errored(unit):
            return name
    return None


def units_for_service(services, service_name):
    units = {}
    service = services[service_name]
    if service.get('Units'):
        units = service['Units']
    if 'SubordinateTo' in service:
        for sub_to in service['SubordinateTo']:
            units.update(services[sub_to].get('Units', {}))
    units = {n: u for n, u in units.items()
             if u.get('PublicAddress')}
    return units


def fail(msg):
    sys.stderr.write('%s\n' % msg)
    sys.exit(1)


def current_charm_name():
    if not os.path.exists('metadata.yaml'):
        return None
    with open('metadata.yaml') as fp:
        metadata = yaml.safe_load(fp)
        return metadata['name']


def parse_charm_id(charm_id):
    charm_match = re.match(r'local:[^/]*/(.*)-\d+', charm_id)
    if charm_match:
        return charm_match.group(1)
    return None


def get_current_service_units(services):
    charm_name = current_charm_name()
    if charm_name:
        for service_name, service in services.items():
            if parse_charm_id(service['Charm']) == charm_name:
                return units_for_service(services, service_name)
    return None


def choose_unit_from(all_units, preferred_units=None):
    if len(all_units) == 1:
        return all_units.items()[0]

    default_unit = find_errored_unit(preferred_units)
    if not default_unit:
        default_unit = find_errored_unit(all_units)
    if not default_unit and preferred_units:
        default_unit = sorted(preferred_units.keys())[0]
    if not default_unit:
        default_unit = sorted(all_units.keys())[0]

    unit_names = sorted(all_units.keys())
    print 'Units:'
    for i, unit_name in enumerate(unit_names):
        unit_err = ''
        if _unit_errored(all_units[unit_name]):
            unit_err = ' (error)'
        print '  %d: %s%s' % (i, unit_name, unit_err)
    print
    selection = raw_input('Select a unit by number or name: %s' %
                          ('[%s] ' % default_unit or ''))
    if selection.isdigit():
        unit = unit_names[int(selection)]
    elif selection == '':
        unit = default_unit
    else:
        unit = selection
    if unit not in all_units:
        fail('Invalid unit: %s' % unit)
    return unit, all_units[unit]


def get_all_units(status):
    services = CaseInsensitiveDict(status.get('applications', status.get('Services')))
    units = {n: CaseInsensitiveDict(u, Charm=s.get('Charm'))
             for s in services.values() if s.get('Units')
             for n, u in s['Units'].iteritems()}
    subordinates = {}
    for name, unit in units.iteritems():
        subs = unit.get('Subordinates') or {}
        for sub_name, sub_unit in subs.iteritems():
            sub_unit['Machine'] = unit['Machine']
            subordinates[sub_name] = sub_unit
    units.update(subordinates)
    return units


def choose_unit(args, opts):
    unit = args.pop(0) if args else None
    status = CaseInsensitiveDict(get_env(opts).status())
    services = status.get('applications', status.get('Services'))
    units = get_all_units(status)
    if not units:
        fail('No units available')
    if unit in units:  # explicit unit given
        return unit, units[unit]
    elif unit in services:  # explicit service given
        units = units_for_service(services, service_name=unit)
        if not units:
            fail('No units available for service: %s' % unit)
        return choose_unit_from(units)
    elif unit:
        fail('Invalid unit: %s' % unit)
    else:
        preferred_units = get_current_service_units(services)
        return choose_unit_from(units, preferred_units)


def upload(unit, local, remote):
    call('rsync', '-Wa', '-e', 'juju ssh --pty=false %s' % unit,
         os.path.expanduser(local), ':%s' % remote)


if __name__ == '__main__':
    opts, args = parse_args()
    if opts.join:
        if len(args) == 0:
            fail('You must provide an address')
        addr = args[0]
        os.execvp('ssh', ['ssh', '-t', 'ubuntu@%s' % addr, 'sudo tmux attach'])
    else:
        unit_name, unit = choose_unit(args, opts)
        config = customize(unit_name, unit, opts)
        model_opt = '-m' if JUJU_2 else '-e'
        if (opts.restart or config.get('auto_restart', False)) and not opts.no_restart:
            subprocess.Popen(
                'sleep 2 ; juju resolved --retry %s %s "%s"' % (model_opt, opts.env, unit_name),
                stdout=subprocess.PIPE, stderr=subprocess.STDOUT, shell=True)
        result = subprocess.call(
            ['/usr/bin/env', 'juju', 'debug-hooks', model_opt, opts.env, unit_name] + args)
        if result != 0:
            sys.exit(result)
        if (opts.sync or config.get('auto_sync', False)) and not opts.no_sync:
            local_charm = current_charm_name()
            remote_charm = parse_charm_id(unit['Charm'])
            if remote_charm == local_charm:
                print 'Syncing remote changes...'
                excludes = list(itertools.chain.from_iterable(
                    [('--exclude', e) for e in config.get('sync_exclude', [])]))
                os.execvp('juju',
                          ['juju', 'sync-charm', '-y', unit_name, '.'] + excludes)
            elif opts.sync:
                print "Unable to sync remote changes: remote charm doesn't match current directory"