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) ILambdaController services to handle action requests
• *:service:commandable-lambda:*:1.0: (optional) ILambdaController services to handle action requests

Constructors

Creates a new instance of this lambda function.

public 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.

public Object act(Map<String, Object> params)

• params: Object - action parameters.
• returns: Object - 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

protected Object execute(Map<String, Object> params) throws ApplicationException

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

getHandler

Gets an entry point into this lambda function.

public Function<Map<String, Object>, ?> getHandler()

• returns: Function<Map<String, Object>, ?> - incoming event object with invocation parameters.

instrument

Gets entry point into this lambda function.

protected InstrumentTiming instrument(IContext context, String name)

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

open

Opens the component.

public void open(IContext) context) throws ApplicationException

• context: IContext - (optional) a context to trace execution through a call chain.

register

Registers all actions in this lambda function.

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

protected void register() throws ReferenceException

registerAction

Registers an action in this lambda function.

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

protected void registerAction(String cmd, Schema schema, Function<Map<String, Object>, ?> action)

• cmd: String - action/command name.
• schema: Schema - validation schema used to validate received parameters.
• action: Function<Map<String, Object>, ?> - action function that is called when the action is invoked.

registerServices

Registers all lambda controllers in the container.

protected void registerControllers() throws UnknownException

run

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

public void run() throws ApplicationExceptio

setReferences

Sets references to dependent components.

public void setReferences(IReferences references) throws ReferenceException, ConfigException

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

Examples

class MyLambdaFunction extends LambdaFunction {
    public MyLambdaFunction() {
        super("mygroup", "MyGroup lambda function");
    }
}

var lambda = new MyLambdaFunction();
 
lambda.run();

See also

• LambdaClient