lbry-sdk/lbrynet/daemon/ComponentManager.py
2018-07-24 20:01:38 -04:00

93 lines
2.8 KiB
Python

import logging
from twisted.internet import defer
log = logging.getLogger(__name__)
class ComponentManager(object):
components = set()
@classmethod
def sort_components(cls, reverse=False):
"""
Sort components by requirements
"""
steps = []
staged = set()
components = set(cls.components)
# components with no requirements
step = []
for component in set(components):
if not component.depends_on:
step.append(component)
staged.add(component.component_name)
components.remove(component)
if step:
steps.append(step)
while components:
step = []
to_stage = set()
for component in set(components):
reqs_met = 0
for needed in component.depends_on:
if needed in staged:
reqs_met += 1
if reqs_met == len(component.depends_on):
step.append(component)
to_stage.add(component.component_name)
components.remove(component)
if step:
staged.update(to_stage)
steps.append(step)
elif components:
raise SyntaxError("components cannot be started: %s" % components)
if reverse:
steps.reverse()
return steps
@classmethod
@defer.inlineCallbacks
def setup(cls):
"""
Start Components in sequence sorted by requirements
:return: (defer.Deferred)
"""
stages = cls.sort_components()
for stage in stages:
yield defer.DeferredList([component._setup() for component in stage])
@classmethod
@defer.inlineCallbacks
def stop(cls):
"""
Stop Components in reversed startup order
:return: (defer.Deferred)
"""
stages = cls.sort_components(reverse=True)
for stage in stages:
yield defer.DeferredList([component._stop() for component in stage])
@classmethod
def all_components_running(cls, *component_names):
"""
:return: (bool) True if all specified components are running
"""
c = {component.component_name: component for component in cls.components}
for component in component_names:
if component not in c:
raise NameError("%s is not a known Component" % component)
if not c[component].running:
return False
return True
@classmethod
def get_component(cls, component_name):
for component in cls.components:
if component.component_name == component_name:
return component
raise NameError(component_name)