lambda

Lambda

The Lambda connector provides the following Actions:

 *  InvokeFunction

Example usage

const val USE_REAL_CLIENT = false

fun main() {
    val deployedLambda = FunctionName("http4kLambda")

    val fakeLambda = FakeLambda(
        deployedLambda to { req: Request ->
            val request = Moshi.asA<Req>(req.bodyString())
            Response(OK)
                .body(Moshi.asFormatString(Resp(request.value)))
        }
    )

    // we can connect to the real service or the fake (drop in replacement)
    val http: HttpHandler = if (USE_REAL_CLIENT) JavaHttpClient() else fakeLambda

    // create a client
    val client = Lambda.Http(Region.of("us-east-1"), { AwsCredentials("accessKeyId", "secretKey") }, http.debug())

    // all operations return a Result monad of the API type
    val invokeResult: Result<Resp, RemoteFailure> = client.invokeFunction(deployedLambda, Req("hello"), Moshi)
    println(invokeResult)
}

Note that the http4k-connect Fake Lambda implementation is designed to provide a runtime environment for function HttpHandlers that will be invoked directly using the Lambda URL pattern (https://lambda.${scope.region}.amazonaws.com/2015-03-31/functions/$name/invocations), rather than being deployed behind APIGateway (where you have total control over the URL pattern where the lambda can be invoked).

The client APIs utilise the http4k-aws module for request signing, which means no dependencies on the incredibly fat Amazon-SDK JARs. This means this integration is perfect for running Serverless Lambdas where binary size is a performance factor.

Default Fake port: 50322

To start:

FakeLambda().start()