class DummyController(IReferenceable, IReconfigurable, IOpenable, INotifiable):
__timer: FixedRateTimer = None
__logger: CompositeLogger = None
__message: str = None
__counter: int = None
def __init__(self):
self.__message = "Hello World!"
self.__logger = CompositeLogger()
self.__timer = FixedRateTimer(self, 1000, 1000)
self.__counter = 0
@property
def message(self) -> str:
return self.__message
@message.setter
def message(self, value: str):
self.__message = value
@property
def counter(self) -> int:
return self.__counter
@counter.setter
def counter(self, value: int):
self.__counter = value
def configure(self, config: ConfigParams):
self.__message = config.get_as_string_with_default("message", self.__message)
def set_references(self, references: IReferences):
self.__logger.set_references(references)
def is_open(self) -> bool:
return self.__timer.is_started()
def open(self, correlation_id: Optional[str]):
self.__timer.start()
self.__logger.trace(correlation_id, "Dummy controller opened")
def close(self, correlation_id: Optional[str]):
self.__timer.stop()
self.__logger.trace(correlation_id, "Dummy controller closed")
def notify(self, correlation_id: Optional[str], args: Parameters):
self.counter += 1
self.__logger.info(correlation_id, "%d - %s", self.counter, self.message)
class Container(IConfigurable, IReferenceable, IUnreferenceable, IOpenable):
"""
Inversion of control (IoC) container that creates components and manages their lifecycle.
The container is driven by configuration, that usually stored in JSON or YAML file.
The configuration contains a list of components identified by type or locator, followed by component configuration.
On container start it performs the following actions:
- Creates components using their types or calls registered factories to create components using their locators
- Configures components that implement IConfigurable interface and passes them their configuration parameters
- Sets references to components that implement IReferenceable interface and passes them references of all components in the container
- Opens components that implement IOpenable interface
On container stop actions are performed in reversed order:
- Closes components that implement ICloseable interface
- Unsets references in components that implement IUnreferenceable interface
- Destroys components in the container.
The component configuration can be parameterized by dynamic values. That allows specialized containers
to inject parameters from command line or from environment variables.
The container automatically creates a ContextInfo component that carries detail information
about the container and makes it available for other components.
### Configuration parameters ###
- name: the context (container or process) name
- description: human-readable description of the context
- properties: entire section of additional descriptive properties
- ...
Example:
.. code-block:: yaml
======= config.yaml ========
- descriptor: mygroup:mycomponent1:default:default:1.0
param1: 123
param2: ABC
- type: mycomponent2,mypackage
param1: 321
param2: XYZ
============================
.. code-block:: python
container = Container()
container.add_factory(MyComponentFactory())
parameters = ConfigParams.from_value(os.env)
container.read_config_from_file("123", "./config/config.yml", parameters)
container.open("123")
print "Container is opened"
# process...
container.close("123")
print "Container is closed"
"""
def __init__(self, name: str = None, description: str = None):
"""
Creates a new instance of the container.
:param name: (optional) a container name (accessible via ContextInfo)
:param description: (optional) a container description (accessible via ContextInfo)
"""
self._config: ContainerConfig = None
self._references: ContainerReferences = None
self._logger: ILogger = NullLogger()
self._info: ContextInfo = ContextInfo(name, description)
self._factories: DefaultContainerFactory = DefaultContainerFactory()
def configure(self, config: ConfigParams):
"""
Configures component by passing configuration parameters.
:param config: configuration parameters to be set.
"""
self._config = ContainerConfig.from_config(config)
def read_config_from_file(self, correlation_id: Optional[str], path: str,
parameters: ConfigParams):
"""
Reads container configuration from JSON or YAML file and parameterizes it with given values.
:param correlation_id: (optional) transaction id to trace execution through call chain.
:param path: a path to configuration file
:param parameters: values to parameters the configuration or null to skip parameterization.
"""
self._config = ContainerConfigReader.read_from_file(
correlation_id, path, parameters)
self._logger.trace(correlation_id, self._config.__str__())
def set_references(self, references: IReferences):
"""
Sets references to dependent components.
:param references: references to locate the component dependencies.
"""
pass
def unset_references(self):
"""
Unsets (clears) previously set references to dependent components.
"""
pass
def __init_references(self, references: IReferences):
# Override in base classes
existingInfo = references.get_one_optional(
DefaultInfoFactory.ContextInfoDescriptor)
if existingInfo is None:
references.put(DefaultInfoFactory.ContextInfoDescriptor,
self._info)
else:
self._info = existingInfo
references.put(
Descriptor("pip-services", "factory", "container", "default",
"1.0"), self._factories)
def add_factory(self, factory: IFactory):
"""
Adds a factory to the container. The factory is used to create components
added to the container by their locators (descriptors).
:param factory: a component factory to be added.
"""
self._factories.add(factory)
def is_open(self) -> bool:
"""
Checks if the component is opened.
:return: true if the component has been opened and false otherwise.
"""
return self._references is not None
def open(self, correlation_id: Optional[str]):
"""
Opens the component.
:param correlation_id: (optional) transaction id to trace execution through call chain.
"""
if self._references is not None:
raise InvalidStateException(correlation_id, "ALREADY_OPENED",
"Container was already opened")
try:
self._logger.trace(correlation_id, "Starting container.")
# Create references with configured components
self._references = ContainerReferences()
self.__init_references(self._references)
self._references.put_from_config(self._config)
self.set_references(self._references)
# Get custom description if available
info_descriptor = Descriptor("*", "context-info", "*", "*", "*")
self._info = self._references.get_one_optional(info_descriptor)
# Reference and open components
self._references.open(correlation_id)
# Get component to logger
self._logger = CompositeLogger(self._references)
self._logger.info(correlation_id,
"Container " + self._info.name + " started.")
except Exception as ex:
self._logger.fatal(correlation_id, ex, "Failed to start container")
self.close(None)
traceback.print_exc()
raise ex
def close(self, correlation_id: Optional[str]):
"""
Closes component and frees used resources.
:param correlation_id: (optional) transaction id to trace execution through call chain.
"""
if self._references is None:
return
try:
self._logger.trace(correlation_id,
"Stopping " + self._info.name + " container")
# Unset references for child container
self.unset_references()
# Close and deference components
self._references.close(correlation_id)
self._references = None
self._logger.info(correlation_id,
"Container " + self._info.name + " stopped")
except Exception as ex:
self._logger.error(correlation_id, ex, "Failed to stop container")
raise ex
class DirectClient(IConfigurable, IReferenceable, IOpenable):
"""
Abstract client that calls controller directly in the same memory space. It is used when multiple microservices are deployed in a single container (monolyth) and communication between them can be done by direct calls rather then through the network.
### Configuration parameters ###
- dependencies:
- controller: override controller descriptor
### References ###
- *:logger:*:*:1.0 (optional) ILogger components to pass log messages
- *:counters:*:*:1.0 (optional) ICounters components to pass collected measurements
- *:controller:*:*:1.0 controller to call business methods
Example:
class MyDirectClient(DirectClient, IMyClient):
def __init__(self):
super(MyDirectClient, self).__init__()
self._dependencyResolver.put('controller', Descriptor("mygroup", "controller", "*", "*", "*"))
...
def get_data(self, correlation_id, id):
timing = self.instrument(correlationId, 'myclient.get_data')
result = self._controller.get_data(correlationId, id)
timing.end_timing()
return result
client = MyDirectClient()
client.set_references(References.from_tuples(Descriptor("mygroup","controller","default","default","1.0"), controller))
data = client.get_data("123", "1")
...
"""
_controller = None
_opened = True
_logger = None
_counters = None
_dependency_resolver = None
def __init__(self):
"""
Creates a new instance of the client.
"""
self._logger = CompositeLogger()
self._counters = CompositeCounters()
self._dependency_resolver = DependencyResolver()
self._dependency_resolver.put('controller', 'none')
def configure(self, config):
"""
Configures component by passing configuration parameters.
:param config: configuration parameters to be set.
"""
self._dependency_resolver.configure(config)
def set_references(self, references):
"""
Sets references to dependent components.
:param references: references to locate the component dependencies.
"""
self._logger.set_references(references)
self._counters.set_references(references)
self._dependency_resolver.set_references(references)
self._controller = self._dependency_resolver.get_one_required('controller')
def _instrument(self, correlation_id, name):
"""
Adds instrumentation to log calls and measure call time. It returns a Timing object that is used to end the time measurement.
:param correlation_id: (optional) transaction id to trace execution through call chain.
:param name: a method name.
:return: Timing object to end the time measurement.
"""
self._logger.trace(correlation_id, f"Executing {name} method")
return self._counters.begin_timing(f"{name} .call_time")
def _instrument_error(self, correlation_id, name, err, result, callback):
"""
Adds instrumentation to error handling.
:param correlation_id: (optional) transaction id to trace execution through call chain.
:param name: a method name.
:param err: an occured error
:param result: (optional) an execution result
:param callback: (optional) an execution callback
"""
if err is not None:
self._logger.error(correlation_id, err, f'Failed to call {name} method')
self._counters.increment_one(f"{name}.call_errors")
if callback:
callback(err, result)
def is_opened(self):
"""
Checks if the component is opened.
:return: true if the component has been opened and false otherwise.
"""
return self._opened
def open(self, correlation_id):
"""
Opens the component.
:param correlation_id: (optional) transaction id to trace execution through call chain.
"""
if self._opened:
return
if self._controller is None:
raise ConnectionException(correlation_id, 'NO_CONTROLLER', 'Controller references is missing')
self._opened = True
self._logger.info(correlation_id, 'Opened direct client')
def close(self, correlation_id):
"""
Closes component and frees used resources.
:param correlation_id: (optional) transaction id to trace execution through call chain.
"""
if self._opened:
self._logger.info(correlation_id, 'Closed direct client')
self._opened = False