docs/compose/config.py

434 lines
12 KiB
Python

import os
import yaml
import six
DOCKER_CONFIG_KEYS = [
'cap_add',
'cap_drop',
'cpu_shares',
'command',
'detach',
'dns',
'dns_search',
'domainname',
'entrypoint',
'env_file',
'environment',
'hostname',
'image',
'links',
'mem_limit',
'net',
'pid',
'ports',
'privileged',
'restart',
'stdin_open',
'tty',
'user',
'volumes',
'volumes_from',
'working_dir',
]
ALLOWED_KEYS = DOCKER_CONFIG_KEYS + [
'build',
'expose',
'external_links',
'name',
]
DOCKER_CONFIG_HINTS = {
'cpu_share': 'cpu_shares',
'link': 'links',
'port': 'ports',
'privilege': 'privileged',
'priviliged': 'privileged',
'privilige': 'privileged',
'volume': 'volumes',
'workdir': 'working_dir',
}
def load(filename):
working_dir = os.path.dirname(filename)
return from_dictionary(load_yaml(filename), working_dir=working_dir, filename=filename)
def from_dictionary(dictionary, working_dir=None, filename=None):
service_dicts = []
for service_name, service_dict in list(dictionary.items()):
if not isinstance(service_dict, dict):
raise ConfigurationError('Service "%s" doesn\'t have any configuration options. All top level keys in your docker-compose.yml must map to a dictionary of configuration options.' % service_name)
loader = ServiceLoader(working_dir=working_dir, filename=filename)
service_dict = loader.make_service_dict(service_name, service_dict)
service_dicts.append(service_dict)
return service_dicts
def make_service_dict(name, service_dict, working_dir=None):
return ServiceLoader(working_dir=working_dir).make_service_dict(name, service_dict)
class ServiceLoader(object):
def __init__(self, working_dir, filename=None, already_seen=None):
self.working_dir = working_dir
self.filename = filename
self.already_seen = already_seen or []
def make_service_dict(self, name, service_dict):
if self.signature(name) in self.already_seen:
raise CircularReference(self.already_seen)
service_dict = service_dict.copy()
service_dict['name'] = name
service_dict = resolve_environment(service_dict, working_dir=self.working_dir)
service_dict = self.resolve_extends(service_dict)
return process_container_options(service_dict, working_dir=self.working_dir)
def resolve_extends(self, service_dict):
if 'extends' not in service_dict:
return service_dict
extends_options = process_extends_options(service_dict['name'], service_dict['extends'])
if self.working_dir is None:
raise Exception("No working_dir passed to ServiceLoader()")
other_config_path = expand_path(self.working_dir, extends_options['file'])
other_working_dir = os.path.dirname(other_config_path)
other_already_seen = self.already_seen + [self.signature(service_dict['name'])]
other_loader = ServiceLoader(
working_dir=other_working_dir,
filename=other_config_path,
already_seen=other_already_seen,
)
other_config = load_yaml(other_config_path)
other_service_dict = other_config[extends_options['service']]
other_service_dict = other_loader.make_service_dict(
service_dict['name'],
other_service_dict,
)
validate_extended_service_dict(
other_service_dict,
filename=other_config_path,
service=extends_options['service'],
)
return merge_service_dicts(other_service_dict, service_dict)
def signature(self, name):
return (self.filename, name)
def process_extends_options(service_name, extends_options):
error_prefix = "Invalid 'extends' configuration for %s:" % service_name
if not isinstance(extends_options, dict):
raise ConfigurationError("%s must be a dictionary" % error_prefix)
if 'service' not in extends_options:
raise ConfigurationError(
"%s you need to specify a service, e.g. 'service: web'" % error_prefix
)
for k, _ in extends_options.items():
if k not in ['file', 'service']:
raise ConfigurationError(
"%s unsupported configuration option '%s'" % (error_prefix, k)
)
return extends_options
def validate_extended_service_dict(service_dict, filename, service):
error_prefix = "Cannot extend service '%s' in %s:" % (service, filename)
if 'links' in service_dict:
raise ConfigurationError("%s services with 'links' cannot be extended" % error_prefix)
if 'volumes_from' in service_dict:
raise ConfigurationError("%s services with 'volumes_from' cannot be extended" % error_prefix)
if 'net' in service_dict:
if get_service_name_from_net(service_dict['net']) is not None:
raise ConfigurationError("%s services with 'net: container' cannot be extended" % error_prefix)
def process_container_options(service_dict, working_dir=None):
for k in service_dict:
if k not in ALLOWED_KEYS:
msg = "Unsupported config option for %s service: '%s'" % (service_dict['name'], k)
if k in DOCKER_CONFIG_HINTS:
msg += " (did you mean '%s'?)" % DOCKER_CONFIG_HINTS[k]
raise ConfigurationError(msg)
service_dict = service_dict.copy()
if 'volumes' in service_dict:
service_dict['volumes'] = resolve_host_paths(service_dict['volumes'], working_dir=working_dir)
if 'build' in service_dict:
service_dict['build'] = resolve_build_path(service_dict['build'], working_dir=working_dir)
return service_dict
def merge_service_dicts(base, override):
d = base.copy()
if 'environment' in base or 'environment' in override:
d['environment'] = merge_environment(
base.get('environment'),
override.get('environment'),
)
if 'volumes' in base or 'volumes' in override:
d['volumes'] = merge_volumes(
base.get('volumes'),
override.get('volumes'),
)
if 'image' in override and 'build' in d:
del d['build']
if 'build' in override and 'image' in d:
del d['image']
list_keys = ['ports', 'expose', 'external_links']
for key in list_keys:
if key in base or key in override:
d[key] = base.get(key, []) + override.get(key, [])
list_or_string_keys = ['dns', 'dns_search']
for key in list_or_string_keys:
if key in base or key in override:
d[key] = to_list(base.get(key)) + to_list(override.get(key))
already_merged_keys = ['environment', 'volumes'] + list_keys + list_or_string_keys
for k in set(ALLOWED_KEYS) - set(already_merged_keys):
if k in override:
d[k] = override[k]
return d
def merge_environment(base, override):
env = parse_environment(base)
env.update(parse_environment(override))
return env
def parse_links(links):
return dict(parse_link(l) for l in links)
def parse_link(link):
if ':' in link:
source, alias = link.split(':', 1)
return (alias, source)
else:
return (link, link)
def get_env_files(options, working_dir=None):
if 'env_file' not in options:
return {}
if working_dir is None:
raise Exception("No working_dir passed to get_env_files()")
env_files = options.get('env_file', [])
if not isinstance(env_files, list):
env_files = [env_files]
return [expand_path(working_dir, path) for path in env_files]
def resolve_environment(service_dict, working_dir=None):
service_dict = service_dict.copy()
if 'environment' not in service_dict and 'env_file' not in service_dict:
return service_dict
env = {}
if 'env_file' in service_dict:
for f in get_env_files(service_dict, working_dir=working_dir):
env.update(env_vars_from_file(f))
del service_dict['env_file']
env.update(parse_environment(service_dict.get('environment')))
env = dict(resolve_env_var(k, v) for k, v in six.iteritems(env))
service_dict['environment'] = env
return service_dict
def parse_environment(environment):
if not environment:
return {}
if isinstance(environment, list):
return dict(split_env(e) for e in environment)
if isinstance(environment, dict):
return environment
raise ConfigurationError(
"environment \"%s\" must be a list or mapping," %
environment
)
def split_env(env):
if '=' in env:
return env.split('=', 1)
else:
return env, None
def resolve_env_var(key, val):
if val is not None:
return key, val
elif key in os.environ:
return key, os.environ[key]
else:
return key, ''
def env_vars_from_file(filename):
"""
Read in a line delimited file of environment variables.
"""
if not os.path.exists(filename):
raise ConfigurationError("Couldn't find env file: %s" % filename)
env = {}
for line in open(filename, 'r'):
line = line.strip()
if line and not line.startswith('#'):
k, v = split_env(line)
env[k] = v
return env
def resolve_host_paths(volumes, working_dir=None):
if working_dir is None:
raise Exception("No working_dir passed to resolve_host_paths()")
return [resolve_host_path(v, working_dir) for v in volumes]
def resolve_host_path(volume, working_dir):
container_path, host_path = split_volume(volume)
if host_path is not None:
host_path = os.path.expanduser(host_path)
host_path = os.path.expandvars(host_path)
return "%s:%s" % (expand_path(working_dir, host_path), container_path)
else:
return container_path
def resolve_build_path(build_path, working_dir=None):
if working_dir is None:
raise Exception("No working_dir passed to resolve_build_path")
_path = expand_path(working_dir, build_path)
if not os.path.exists(_path) or not os.access(_path, os.R_OK):
raise ConfigurationError("build path %s either does not exist or is not accessible." % _path)
else:
return _path
def merge_volumes(base, override):
d = dict_from_volumes(base)
d.update(dict_from_volumes(override))
return volumes_from_dict(d)
def dict_from_volumes(volumes):
if volumes:
return dict(split_volume(v) for v in volumes)
else:
return {}
def volumes_from_dict(d):
return [join_volume(v) for v in d.items()]
def split_volume(string):
if ':' in string:
(host, container) = string.split(':', 1)
return (container, host)
else:
return (string, None)
def join_volume(pair):
(container, host) = pair
if host is None:
return container
else:
return ":".join((host, container))
def expand_path(working_dir, path):
return os.path.abspath(os.path.join(working_dir, path))
def to_list(value):
if value is None:
return []
elif isinstance(value, six.string_types):
return [value]
else:
return value
def get_service_name_from_net(net_config):
if not net_config:
return
if not net_config.startswith('container:'):
return
_, net_name = net_config.split(':', 1)
return net_name
def load_yaml(filename):
try:
with open(filename, 'r') as fh:
return yaml.safe_load(fh)
except IOError as e:
raise ConfigurationError(six.text_type(e))
class ConfigurationError(Exception):
def __init__(self, msg):
self.msg = msg
def __str__(self):
return self.msg
class CircularReference(ConfigurationError):
def __init__(self, trail):
self.trail = trail
@property
def msg(self):
lines = [
"{} in {}".format(service_name, filename)
for (filename, service_name) in self.trail
]
return "Circular reference:\n {}".format("\n extends ".join(lines))