serveless implementation using aws compute engine and serverless framework

2018-02-08 12:03:00 -05:00
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+---
+layout: pattern
+title: serverless
+folder: serverless
+permalink: /patterns/serverless/
+categories: Architectural
+tags:
+ - Java
+ - Difficulty-Intermittent
+---
+
+## Serverless
+
+Serverless eliminates the need to plan for infrastructure and let's you focus on your 
+application. 
+
+## Intent
+
+Whether to reduce your infrastructure costs, shrink the time you spend on ops tasks, 
+simplify your deployment processes, reach infinite scalability, serverless cuts time 
+to market in half.
+ 
+## Explanation
+
+Serverless computing is a cloud computing execution model in which the cloud provider 
+dynamically manages the allocation of machine resources. Pricing is based on the 
+actual amount of resources consumed by an application, rather than on pre-purchased 
+units of capacity. 
+
+## Serverless framework
+
+[Serverless](https://serverless.com/) is a toolkit for deploying and operating serverless architectures. 
+
+## (Function as a Service or "FaaS")
+
+The term ‘Serverless’ is confusing since with such applications there are both server 
+hardware and server processes running somewhere, but the difference to normal 
+approaches is that the organization building and supporting a ‘Serverless’ application
+ is not looking after the hardware or the processes - they are outsourcing this to a vendor.
+
+Some of the Serverless Cloud Providers are 
+
+![https://serverless.com/framework/docs/providers/aws/](./etc/aws-black.png "aws")
+![https://serverless.com/framework/docs/providers/azure/](./etc/azure-black.png "azure")
+![https://serverless.com/framework/docs/providers/openwhisk/](./etc/openwhisk-black.png "openwhisk")
+![https://serverless.com/framework/docs/providers/google/](./etc/gcf-black.png "google")
+![https://serverless.com/framework/docs/providers/kubeless/](./etc/kubeless-logos-black.png "kubeless")
+![https://serverless.com/framework/docs/providers/spotinst/](./etc/spotinst-logos-black-small.png "spotinst")
+![https://serverless.com/framework/docs/providers/webtasks/](./etc/webtask-small-grayscale.png "webtask")
+...
+
+Anything that triggers an Lambda Function to execute is regarded by the Framework as 
+an Event. Most of the Serverless Cloud Providers support following Events
+- Http
+- PubSub Events
+- scheduled
+
+AWS supports processing event generated from AWS Services (S3/Cloudwatch/etc) and 
+using aws as a compute engine is our first choice.
+
+## AWS lambda function implementation
+
+AWS lambda SDK provides pre-defined interface `com.amazonaws.services.lambda.runtime
+.RequestHandler` to implement our lambda function. 
+
+```java
+public class LambdaInfoApiHandler implements RequestHandler<Map<String, Object>, ApiGatewayResponse> {
+
+  private static final Logger LOG = Logger.getLogger(LambdaInfoApiHandler.class);
+  private static final Integer SUCCESS_STATUS_CODE = 200;
+
+
+  @Override
+  public ApiGatewayResponse handleRequest(Map<String, Object> input, Context context) {
+    
+  }
+}
+```
+handleRequest method is where the function code is implemented. Context provides 
+useful information about Lambda execution environment. AWS Lambda function needs a 
+deployment package. This package is either a .zip or .jar file that contains all the 
+dependencies of the function.
+
+`serverless.yml` contains configuration to manage deployments for your functions.
+
+## Run example in local
+
+# Pre-requisites
+* Node.js v6.5.0 or later.
+* Serverless CLI v1.9.0 or later. You can run npm install -g serverless to install it.
+* An AWS account. If you don't already have one, you can sign up for a free trial that includes 1 million free Lambda requests per month.
+* [Set-up](https://serverless.com/framework/docs/providers/aws/guide/credentials/) your Provider Credentials. Watch the video on setting up credentials
+
+# build and deploy
+
+* `cd serverless`
+* `mvn clean package`
+* `serverless deploy --stage=dev --verbose`
+
+Based on the configuration in `serverless.yml` serverless framework creates a
+cloud formation stack for S3 (ServerlessDeploymentBucket), IAM Role 
+(IamRoleLambdaExecution), cloud watch (log groups), API Gateway (ApiGatewayRestApi) 
+and the Lambda function. 
+
+The command will print out Stack Outputs which looks something like this
+
+```yaml
+endpoints:
+  GET - https://xxxxxxxxx.execute-api.us-east-1.amazonaws.com/dev/info
+```
+
+```yaml
+CurrentTimeLambdaFunctionQualifiedArn: arn:aws:lambda:us-east-1:xxxxxxxxxxx:function:lambda-info-http-endpoint-dev-currentTime:4
+ServiceEndpoint: https://xxxxxxxxx.execute-api.us-east-1.amazonaws.com/dev
+ServerlessDeploymentBucketName: lambda-info-http-endpoin-serverlessdeploymentbuck-2u8uz2i7cap2
+```
+access the endpoint to invoke the function.
+
+## Credits
+
+* [serverless docs](https://serverless.com/framework/docs/)
+* [Serverless Architectures](https://martinfowler.com/articles/serverless.html)