LambdaFunction

Implements: Container

Description

The LambdaFunction class allows you to create an abstract AWS Lambda function that acts as a container to instantiate and run components, and expose them via an external entry point.

Important points

• When handling calls the “cmd” parameter determines what action shall be called, while the other parameters are passed to the action itself.

• Container configuration for this Lambda function is stored in "./config/config.yml" file. But this path can be overriden by the CONFIG_PATH environment variable.

References

• *:logger:*:*:1.0: (optional) ILogger components to pass log messages.
• *:counters:*:*:1.0: (optional) ICounters components to pass collected measurements.
• *:service:lambda:*:1.0: (optional) ILambdaService services to handle action requests
• *:service:commandable-lambda:*:1.0: (optional) ILambdaService services to handle action requests

Constructors

Creates a new instance of this lambda function.

LambdaFunction(name: str, description: str = None)

• name: str - (optional) container name (accessible via ContextInfo).
• description: str - (optional) container description (accessible via ContextInfo).

Fields

Instance methods

act

Calls registered action in this lambda function. The “cmd” parameter in the action parameters determines what action shall be called.

• This method shall only be used in testing.

act(params: dict): Any

• params: dict - action parameters.
• returns: Any - result

_execute

Executes this AWS Lambda function and returns the result. This method can be overloaded in child classes if it is necessary to change the default behavior

_execute(event: dict): Any

• event: dict - event parameters (or function arguments)
• returns: Any - result of the function execution.

get_handler

Gets an entry point into this lambda function.

get_handler(): Callable[[dict], Any]

• returns: Callable[[dict], Any] - incoming event object with invocation parameters.

_instrument

Gets entry point into this lambda function.

_instrument(correlation_id: Optional[str], name: str): InstrumentTiming

• correlation_id: Optional[str] - (optional) transaction id used to trace execution through the call chain.
• name: str - method name.
• returns: InstrumentTiming - object to end the time measurement.

open

Opens the component.

open(correlation_id: Optional[str])

• correlationId: Optional[str] - (optional) transaction id used to trace execution through the call chain.

register

Registers all actions in this lambda function.

• Note: Overloading of this method has been deprecated. Use LambdaService instead.

register()

_register_action

Registers an action in this lambda function.

• Note: This method has been deprecated. Use LambdaService instead.

_register_action(cmd: str, schema: Optional[Schema], action: Callable[[dict], Any])

• cmd: str - action/command name.
• schema: Optional[Schema] - validation schema used to validate received parameters.
• action: Callable[[dict], Any] - action function that is called when the action is invoked.

_register_services

Registers all lambda services in the container.

_register_services()

run

Runs this lambda function, loads container configuration, instantiates components and manages their lifecycle. Makes this function ready to access action calls.

run()

set_references

Sets references to dependent components.

set_references(references: IReferences)

• references: IReferences - references to locate the component’s dependencies.

Examples

class MyLambdaFunction(LambdaFunction):
    def __init__(self):
        super().__init__("mygroup", "MyGroup lambda function")
lambda = MyLambdaFunction()

service.run();
print("MyLambdaFunction is started")

See also

• LambdaClient