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updates to service dependency resolution to allow for multithreaded startup, also improved tests to validate service boot ordering for expected outcomes

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This commit is contained in:
Blake Harnden 2020-08-21 11:34:12 -07:00
parent f687115522
commit 05247524d7
2 changed files with 121 additions and 31 deletions
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52
daemon/core/services/coreservices.py
View file

@ -53,18 +53,34 @@ class ServiceDependencies:
def __init__(self, services: List["CoreServiceType"]) -> None:
self.visited: Set[str] = set()
self.boot: List["CoreServiceType"] = []
self.services: Dict[str, "CoreServiceType"] = {}
self.paths: Dict[str, List["CoreServiceType"]] = {}
self.boot_paths: List[List["CoreServiceType"]] = []
roots = set([x.name for x in services])
for service in services:
self.services[service.name] = service
roots -= set(service.dependencies)
self.roots: List["CoreServiceType"] = [x for x in services if x.name in roots]
if services and not self.roots:
raise ValueError("circular dependency is present")
def _search(self, service: "CoreServiceType", visiting: Set[str] = None) -> None:
def _search(
self,
service: "CoreServiceType",
visiting: Set[str] = None,
path: List[str] = None,
) -> List["CoreServiceType"]:
if service.name in self.visited:
return
return self.paths[service.name]
self.visited.add(service.name)
if visiting is None:
visiting = set()
visiting.add(service.name)
if path is None:
for dependency in service.dependencies:
path = self.paths.get(dependency)
if path is not None:
break
for dependency in service.dependencies:
service_dependency = self.services.get(dependency)
if not service_dependency:
@ -72,14 +88,19 @@ class ServiceDependencies:
if dependency in visiting:
raise ValueError(f"circular dependency, already visited: {dependency}")
else:
self._search(service_dependency, visiting)
path = self._search(service_dependency, visiting, path)
visiting.remove(service.name)
self.boot.append(service)
if path is None:
path = []
self.boot_paths.append(path)
path.append(service)
self.paths[service.name] = path
return path
def boot_order(self) -> List["CoreServiceType"]:
for service in self.services.values():
def boot_order(self) -> List[List["CoreServiceType"]]:
for service in self.roots:
self._search(service)
return self.boot
return self.boot_paths
class ServiceShim:
@ -422,13 +443,22 @@ class CoreServices:
:param node: node to start services on
:return: nothing
"""
services = ServiceDependencies(node.services).boot_order()
boot_paths = ServiceDependencies(node.services).boot_order()
funcs = []
for boot_path in boot_paths:
args = (node, boot_path)
funcs.append((self._boot_service_path, args, {}))
result, exceptions = utils.threadpool(funcs)
if exceptions:
raise ServiceBootError(*exceptions)
def _boot_service_path(self, node: CoreNode, boot_path: List["CoreServiceType"]):
logging.info(
"booting node(%s) services: %s",
node.name,
" -> ".join([x.name for x in services]),
" -> ".join([x.name for x in boot_path]),
)
for service in services:
for service in boot_path:
service = self.get_service(node.id, service.name, default_service=True)
try:
self.boot_service(node, service)

92
daemon/tests/test_services.py
View file

@ -220,7 +220,7 @@ class TestServices:
assert default_service == my_service
assert custom_service and custom_service != my_service
def test_services_dependencies(self):
def test_services_dependency(self):
# given
service_a = CoreService()
service_a.name = "a"
@ -238,20 +238,34 @@ class TestServices:
service_d.dependencies = ()
service_e.dependencies = ()
services = [service_a, service_b, service_c, service_d, service_e]
expected1 = {service_a.name, service_b.name, service_c.name, service_d.name}
expected2 = [service_e]
# when
results = []
permutations = itertools.permutations(services)
for permutation in permutations:
permutation = list(permutation)
result = ServiceDependencies(permutation).boot_order()
results.append(result)
results = ServiceDependencies(permutation).boot_order()
# then
for result in results:
assert len(result) == len(services)
result_set = {x.name for x in result}
if len(result) == 4:
a_index = result.index(service_a)
b_index = result.index(service_b)
c_index = result.index(service_c)
d_index = result.index(service_d)
assert b_index < a_index
assert b_index < c_index
assert d_index < c_index
assert result_set == expected1
elif len(result) == 1:
assert expected2 == result
else:
raise ValueError(
f"unexpected result: {results}, perm({permutation})"
)
def test_services_missing_dependency(self):
def test_services_dependency_missing(self):
# given
service_a = CoreService()
service_a.name = "a"
@ -271,7 +285,7 @@ class TestServices:
with pytest.raises(ValueError):
ServiceDependencies(permutation).boot_order()
def test_services_dependencies_cycle(self):
def test_services_dependency_cycle(self):
# given
service_a = CoreService()
service_a.name = "a"
@ -291,7 +305,7 @@ class TestServices:
with pytest.raises(ValueError):
ServiceDependencies(permutation).boot_order()
def test_services_common_dependency(self):
def test_services_dependency_common(self):
# given
service_a = CoreService()
service_a.name = "a"
@ -299,18 +313,64 @@ class TestServices:
service_b.name = "b"
service_c = CoreService()
service_c.name = "c"
service_b.dependencies = (service_a.name,)
service_c.dependencies = (service_a.name, service_b.name)
services = [service_a, service_b, service_c]
service_d = CoreService()
service_d.name = "d"
service_a.dependencies = (service_b.name,)
service_c.dependencies = (service_d.name, service_b.name)
services = [service_a, service_b, service_c, service_d]
expected = {service_a.name, service_b.name, service_c.name, service_d.name}
# when
results = []
permutations = itertools.permutations(services)
for permutation in permutations:
permutation = list(permutation)
result = ServiceDependencies(permutation).boot_order()
results.append(result)
results = ServiceDependencies(permutation).boot_order()
# then
for result in results:
assert result == [service_a, service_b, service_c]
assert len(result) == 4
result_set = {x.name for x in result}
a_index = result.index(service_a)
b_index = result.index(service_b)
c_index = result.index(service_c)
d_index = result.index(service_d)
assert b_index < a_index
assert d_index < c_index
assert b_index < c_index
assert expected == result_set
def test_services_dependency_common2(self):
# given
service_a = CoreService()
service_a.name = "a"
service_b = CoreService()
service_b.name = "b"
service_c = CoreService()
service_c.name = "c"
service_d = CoreService()
service_d.name = "d"
service_a.dependencies = (service_b.name,)
service_b.dependencies = (service_c.name, service_d.name)
service_c.dependencies = (service_d.name,)
services = [service_a, service_b, service_c, service_d]
expected = {service_a.name, service_b.name, service_c.name, service_d.name}
# when
permutations = itertools.permutations(services)
for permutation in permutations:
permutation = list(permutation)
results = ServiceDependencies(permutation).boot_order()
# then
for result in results:
assert len(result) == 4
result_set = {x.name for x in result}
a_index = result.index(service_a)
b_index = result.index(service_b)
c_index = result.index(service_c)
d_index = result.index(service_d)
assert b_index < a_index
assert c_index < b_index
assert d_index < b_index
assert d_index < c_index
assert expected == result_set