docs/compose/config/sort_services.py

56 lines
1.8 KiB
Python

from compose.config.errors import DependencyError
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 sort_service_dicts(services):
# Topological sort (Cormen/Tarjan algorithm).
unmarked = services[:]
temporary_marked = set()
sorted_services = []
def get_service_names(links):
return [link.split(':')[0] for link in links]
def get_service_names_from_volumes_from(volumes_from):
return [volume_from.source for volume_from in volumes_from]
def get_service_dependents(service_dict, services):
name = service_dict['name']
return [
service for service in services
if (name in get_service_names(service.get('links', [])) or
name in get_service_names_from_volumes_from(service.get('volumes_from', [])) or
name == get_service_name_from_net(service.get('net')))
]
def visit(n):
if n['name'] in temporary_marked:
if n['name'] in get_service_names(n.get('links', [])):
raise DependencyError('A service can not link to itself: %s' % n['name'])
if n['name'] in n.get('volumes_from', []):
raise DependencyError('A service can not mount itself as volume: %s' % n['name'])
else:
raise DependencyError('Circular import between %s' % ' and '.join(temporary_marked))
if n in unmarked:
temporary_marked.add(n['name'])
for m in get_service_dependents(n, services):
visit(m)
temporary_marked.remove(n['name'])
unmarked.remove(n)
sorted_services.insert(0, n)
while unmarked:
visit(unmarked[-1])
return sorted_services