# Simple HTTP Endpoint Example This example demonstrates how to setup a simple HTTP GET endpoint using Java. Once you ping it, it will reply with the current time. [Jackson](https://github.com/FasterXML/jackson) is used to serialize objects to JSON. ## Use Cases - Wrapping an existing internal or external endpoint/service ## Build It is required to build prior to deploying. You can build the deployment artifact using Gradle or Maven. ### Gradle In order to build using Gradle simply run ```bash gradle wrapper # to build the gradle wrapper jar ./gradlew build # to build the application jar ``` The expected result should be similar to: ```bash Starting a Gradle Daemon, 1 incompatible Daemon could not be reused, use --status for details :compileJava :processResources :classes :jar :assemble :buildZip :compileTestJava UP-TO-DATE :processTestResources UP-TO-DATE :testClasses UP-TO-DATE :test UP-TO-DATE :check UP-TO-DATE :build BUILD SUCCESSFUL Total time: 8.195 secs ``` ### Maven In order to build using Maven simply run ```bash mvn package ``` Note: you can install Maven with 1. [sdkman](http://sdkman.io/) using "sdk install maven" (yes, use as default) 2. sudo apt-get install mvn 3. brew install maven If you use Maven to build, then in `serverless.yml` you have to replace ```yaml package: artifact: build/distributions/aws-java-simple-http-endpoint.zip ``` by ```yaml package: artifact: target/aws-java-simple-http-endpoint.jar ``` before deploying. ## Deploy After having built the deployment artifact using Gradle or Maven as described above you can deploy by simply running ```bash serverless deploy ``` The expected result should be similar to: ```bash Serverless: Creating Stack... Serverless: Checking Stack create progress... ..... Serverless: Stack create finished... Serverless: Uploading CloudFormation file to S3... Serverless: Uploading service .zip file to S3... Serverless: Updating Stack... Serverless: Checking Stack update progress... .............................. Serverless: Stack update finished... Service Information service: aws-java-simple-http-endpoint stage: dev region: us-east-1 api keys: None endpoints: GET - https://XXXXXXX.execute-api.us-east-1.amazonaws.com/dev/ping functions: aws-java-simple-http-endpoint-dev-currentTime: arn:aws:lambda:us-east-1:XXXXXXX:function:aws-java-simple-http-endpoint-dev-currentTime ``` ## Usage You can now invoke the Lambda function directly and even see the resulting log via ```bash serverless invoke --function currentTime --log ``` The expected result should be similar to: ```bash { "statusCode": 200, "body": "{\"message\":\"Hello, the current time is Wed Jan 04 23:44:37 UTC 2017\"}", "headers": { "X-Powered-By": "AWS Lambda & Serverless", "Content-Type": "application/json" }, "isBase64Encoded": false } -------------------------------------------------------------------- START RequestId: XXXXXXX Version: $LATEST 2017-01-04 23:44:37 INFO com.serverless.Handler:18 - received: {} END RequestId: XXXXXXX REPORT RequestId: XXXXXXX Duration: 0.51 ms Billed Duration: 100 ms Memory Size: 1024 MB Max Memory Used: 53 MB ``` Finally you can send an HTTP request directly to the endpoint using a tool like curl ```bash curl https://XXXXXXX.execute-api.us-east-1.amazonaws.com/dev/ping ``` The expected result should be similar to: ```bash {"message": "Hello, the current time is Wed Jan 04 23:44:37 UTC 2017"}% ``` ## Scaling By default, AWS Lambda limits the total concurrent executions across all functions within a given region to 100. The default limit is a safety limit that protects you from costs due to potential runaway or recursive functions during initial development and testing. To increase this limit above the default, follow the steps in [To request a limit increase for concurrent executions](http://docs.aws.amazon.com/lambda/latest/dg/concurrent-executions.html#increase-concurrent-executions-limit).