org.http4k.serverless.AwsLambdaRuntime.kt Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of http4k-serverless-lambda-runtime Show documentation

Http4k Serverless support for AWS Lambda

The newest version!

package org.http4k.serverless

import com.amazonaws.services.lambda.runtime.Context
import org.http4k.client.JavaHttpClient
import org.http4k.core.HttpHandler
import org.http4k.core.Uri
import org.http4k.core.then
import org.http4k.filter.ClientFilters.SetHostFrom
import org.http4k.server.Http4kServer
import java.util.concurrent.atomic.AtomicBoolean
import kotlin.concurrent.thread

/**
 * Controls the function execution loop. Continues to process events to this function
 * until either it encounters an operational error or AWS terminates the runtime.
 */
class AwsLambdaRuntime(
    private val env: Map = System.getenv(),
    private val http: HttpHandler = JavaHttpClient(),
) : ServerlessConfig {
    override fun asServer(fn: FnLoader) = object : Http4kServer {

        @Suppress("HttpUrlsUsage")
        private val runtime = LambdaRuntimeAPI(
            SetHostFrom(Uri.of("http://${env.getValue("AWS_LAMBDA_RUNTIME_API")}")).then(http)
        )

        private val done = AtomicBoolean(false)

        override fun port() = throw UnsupportedOperationException("not port bound")

        override fun start() = apply {
            val lambda = try {
                fn(env)
            } catch (e: Exception) {
                runtime.initError(e)
                throw e
            }

            thread {
                do {
                    runtime.nextInvocation().use { nextInvocation ->
                        try {
                            lambda(nextInvocation.body.stream, LambdaEnvironmentContext(nextInvocation, env)).use {
                                runtime.success(nextInvocation, it)
                            }
                        } catch (e: Exception) {
                            runtime.error(nextInvocation, e)
                        }
                    }
                } while (!done.get())
            }
        }

        override fun stop() = apply { done.set(true) }
    }
}