Service¶
service management framework allowing for service discovery and transparent remoting including multiple possible transport protocols.
BaseDescriptor(type, decorator)
¶
Bases: Generic[T]
the base class for the meta data of both services and components.
Channel()
¶
Bases: InvocationHandler, ABC
A channel is a dynamic proxy invocation handler and transparently takes care of remoting.
FirstURLSelector
¶
RoundRobinURLSelector()
¶
URLSelector
¶
a url selector retrieves a URL for the next remoting call.
get(urls)
abstractmethod
¶
return the next URL given a list of possible URLS
Parameters:
| Name | Type | Description | Default |
|---|---|---|---|
urls
|
list[str]
|
list of possible URLS |
required |
Returns:
| Type | Description |
|---|---|
str
|
a URL |
select_first_url()
¶
pick the first URL
select_round_robin()
¶
enable round robin
ChannelAddress(channel, uri)
dataclass
¶
A channel address is a combination of:
- channel: the channel name
- uri: uri of the appropriate endpoint
ChannelInstances(component, channel, urls=[])
dataclass
¶
a resolved channel address containing:
- component: the component name
- channel: the channel name
- urls: list of URLs
ChannelManager()
¶
Internal factory for channels.
Component
¶
Bases: Service
This is the base class for components.
get_addresses(port)
abstractmethod
¶
returns a list of channel addresses that expose this component's services.
Parameters:
| Name | Type | Description | Default |
|---|---|---|---|
port
|
int
|
the port of a server hosting this component |
required |
Returns:
| Type | Description |
|---|---|
list[ChannelAddress]
|
list of channel addresses |
get_health()
abstractmethod
async
¶
return the component health
Returns: the component health
get_status()
abstractmethod
¶
return the component status callback
Returns: the component status
shutdown()
abstractmethod
¶
shutdown callback
startup()
abstractmethod
¶
startup callback
ComponentDescriptor(component_type, service_types)
¶
ComponentRegistry
¶
A component registry keeps track of components including their health
deregister(descriptor)
abstractmethod
¶
deregister a component from the registry Args: descriptor: the component descriptor
get_addresses(descriptor)
abstractmethod
¶
return a list of addresses that can be used to call services belonging to this component
Parameters:
| Name | Type | Description | Default |
|---|---|---|---|
descriptor
|
ComponentDescriptor
|
the component descriptor |
required |
Returns:
| Type | Description |
|---|---|
list[ChannelInstances]
|
list of channel instances |
register(descriptor, addresses)
abstractmethod
¶
register a component to the registry Args: descriptor: the descriptor addresses: list of addresses
watch(channel)
abstractmethod
¶
remember the passed channel and keep it informed about address changes Args: channel: a channel
ComponentStatus
¶
Bases: Enum
A component is in one of the following statuses:
- VIRGIN: just constructed
- RUNNING: registered and up and running
- STOPPED: after shutdown
LocalServiceException
¶
Bases: ServiceException
base class for service exceptions occurring locally
RemoteServiceException
¶
Bases: ServiceException
base class for service exceptions occurring on the server side
Server()
¶
Bases: ABC
A server is a central entity that boots a main module and initializes the ServiceManager. It also is the place where http servers get initialized.
get_local_ip()
classmethod
¶
return the local ip address
Returns: the local ip address
Service
¶
This is something like a 'tagging interface' for services.
ServiceCommunicationException
¶
Bases: ServiceException
base class for service exceptions thrown by remoting errors
ServiceDescriptor(component_descriptor, service_type)
¶
ServiceException
¶
Bases: Exception
base class for service exceptions
ServiceInstanceProvider(clazz)
¶
ServiceManager(component_registry, channel_manager)
¶
Central class that manages services and components and is able to return proxies.
get_service(service_type, preferred_channel='')
¶
return a service proxy given a service type and preferred channel name
Parameters:
| Name | Type | Description | Default |
|---|---|---|---|
service_type
|
Type[T]
|
the service type |
required |
preferred_channel
|
the preferred channel name |
''
|
Returns:
| Type | Description |
|---|---|
T
|
the proxy |
channel(name)
¶
this decorator is used to mark channel implementations.
Parameters:
| Name | Type | Description | Default |
|---|---|---|---|
name
|
str
|
the channel name |
required |
component(name='', description='', services=[])
¶
decorates component interfaces
Parameters:
| Name | Type | Description | Default |
|---|---|---|---|
name
|
the component name. If empty the class name converted to snake-case is used |
''
|
|
description
|
optional description |
''
|
|
services
|
list[Type]
|
the list of hosted services |
[]
|
health(endpoint='')
¶
specifies the health endpoint that will return the component health
Parameters:
| Name | Type | Description | Default |
|---|---|---|---|
endpoint
|
the health endpoint |
''
|
implementation()
¶
decorates service or component implementations.
service(name='', description='')
¶
decorates service interfaces
Parameters:
| Name | Type | Description | Default |
|---|---|---|---|
name
|
the service name. If empty the class name converted to snake case is used |
''
|
|
description
|
optional description |
''
|