LambdaFunction

Extends: 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 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([String name, String description])

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

Future act(params)

• params: dynamic - action parameters.
• returns: Future - result

getHandler

Gets an entry point into this lambda function.

aws.Handler<aws.AwsApiGatewayEvent> getHandler()

• returns: aws.Handler<aws.AwsApiGatewayEvent> - incoming event object with invocation parameters.

instrument

Gets entry point into this lambda function.

CounterTiming instrument(IContext context, String name)

• context: IContext - (optional) a context to trace execution through a call chain.
• name: String - method name.
• returns: CounterTiming - object to end the time measurement.

register

Registers all actions in this lambda function.

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

void register()

registerAction

Registers an action in this lambda function.

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

void registerAction(String cmd, Schema schema, Future Function(dynamic) action)

• cmd: String - action/command name.
• schema: Schema - validation schema used to validate received parameters.
• action: Future Function(dynamic) - action function that is called when the action is invoked.

run

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

Future run()

setReferences

Sets references to dependent components.

@override

void setReferences(IReferences references)

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

Examples

     class MyLambdaFunction extends LambdaFunction {
         IMyController _service;
         ...
         MyLambdaFunction()
             super('mygroup', 'MyGroup lambda function'){
             dependencyResolver.put(
                 'service',
                 Descriptor('mygroup','service','*','*','1.0')
             );
         }

         void setReferences(IReferences references) {
             super.setReferences(references);
             _service = dependencyResolver.getRequired<IMyController>('service');
         }

         Future getMyData(params) async {
           return await _service.getMyData(params['trace_id'],
             params['id']),
         }

         void register() {
         registerAction(
           'get_mydata',
           ObjectSchema(true).withOptionalProperty('id', TypeCode.String),
           getMyData);
         }
             ...
     }

     var lambda = MyLambdaFunction();

     await lambda.run();
     print('MyLambdaFunction is started');

     var result = await lambda.act({'cmd': 'get_dummies'});
     print(result);

See also

• LambdaClient