Example Demonstrating Spring Cloud Function Framework + AWS Lambda + Serverless Framework

This example uses Serverless Framework to deploy a Spring Cloud Function on AWS Lambda Platform.

Quick introduction to Spring Cloud Function

Spring Cloud Function provides an uniform programming model to develop functions which can be run on any FaaS platforms like AWS Lambda. The same code can run as a web endpoint, a stream processor, or a task. Also, enables Spring Boot features. More information is availabe at Spring Cloud Function

Example project

Use-case

This is a scenario in which when we provide a Member ID from Health Insurance Card, the service should reply with the type of coverage that member has. In this fictional scenario it always returns a coverage type as MEDICAL for a given Member ID.

Function

{% highlight java %}

@Bean
public Function<HealthFirstMemberRequest, HealthFirstMemberResponse> members() {
	return member -> {
		HealthFirstMemberResponse response = new HealthFirstMemberResponse();
		response.setMemberId(member.getMemberId());
		response.setCoverage(HealthFirstMemberResponse.Coverage.MEDICAL);
	    return response;
    };
}

{% endhighlight %}

AWS Lambda Handler

A Handler class which just implements SpringBootRequestHandler is needed. This is what we are going to configure in serverless.yml file.

Maven POM file

The following dependencies in POM.xml file does all the magic of generating AWS specific Lambda code.

<dependency>
  <groupId>org.springframework.cloud</groupId>
  <artifactId>spring-cloud-function-adapter-aws</artifactId>
</dependency>
<dependency>
  <groupId>com.amazonaws</groupId>
  <artifactId>aws-lambda-java-core</artifactId>
  <version>${aws-lambda-core.version}</version>
  <scope>provided</scope>
</dependency>

Setup

Generate deployable Artifacts

Run following command to generate deployable / uploadable .jar file.

$mvn clean package

This gnerates a JAR file 'member-function-0.0.1-SNAPSHOT-aws.jar' under target folder. Serverless Framework uploads this JAR file to AWS Lambda.

serverless.yml

We define the serverless.yml file with all the settings needed.

service: sls-aws-spring-cloud-function
provider:
  name: aws
  runtime: java8
  timeout: 10
package:
  artifact: target/aws-java-spring-cloud-function-demo-0.0.1-SNAPSHOT-aws.jar
functions:
  members:
    handler: com.healthfirst.memberfunction.AwsLambdaHandler
    environment:
      FUNCTION_NAME: members

Deployment

Please run following command to deploy the project on AWS Lambda

$sls deploy -v --aws-profle <your AWS profile name>

You would see something similar to this

Serverless: Packaging service...
Serverless: Creating Stack...
Serverless: Checking Stack create progress...
CloudFormation - CREATE_IN_PROGRESS - AWS::CloudFormation::Stack - sls-aws-java-spring-cloud-function-demo-dev
CloudFormation - CREATE_IN_PROGRESS - AWS::S3::Bucket - ServerlessDeploymentBucket
CloudFormation - CREATE_IN_PROGRESS - AWS::S3::Bucket - ServerlessDeploymentBucket
CloudFormation - CREATE_COMPLETE - AWS::S3::Bucket - ServerlessDeploymentBucket
CloudFormation - CREATE_COMPLETE - AWS::CloudFormation::Stack - sls-aws-java-spring-cloud-function-demo-dev
Serverless: Stack create finished...
Serverless: Uploading CloudFormation file to S3...
Serverless: Uploading artifacts...
Serverless: Uploading service .zip file to S3 (12.91 MB)...
Serverless: Validating template...
Serverless: Updating Stack...
Serverless: Checking Stack update progress...
CloudFormation - UPDATE_IN_PROGRESS - AWS::CloudFormation::Stack - sls-aws-java-spring-cloud-function-demo-dev
CloudFormation - CREATE_IN_PROGRESS - AWS::Logs::LogGroup - MembersLogGroup
CloudFormation - CREATE_IN_PROGRESS - AWS::IAM::Role - IamRoleLambdaExecution
CloudFormation - CREATE_IN_PROGRESS - AWS::Logs::LogGroup - MembersLogGroup
CloudFormation - CREATE_IN_PROGRESS - AWS::IAM::Role - IamRoleLambdaExecution
CloudFormation - CREATE_COMPLETE - AWS::Logs::LogGroup - MembersLogGroup
CloudFormation - CREATE_COMPLETE - AWS::IAM::Role - IamRoleLambdaExecution
CloudFormation - CREATE_IN_PROGRESS - AWS::Lambda::Function - MembersLambdaFunction
CloudFormation - CREATE_IN_PROGRESS - AWS::Lambda::Function - MembersLambdaFunction
CloudFormation - CREATE_COMPLETE - AWS::Lambda::Function - MembersLambdaFunction
CloudFormation - CREATE_IN_PROGRESS - AWS::Lambda::Version - MembersLambdaVersionN8TC7eR31v5vRUjauJUxtjhrj6n1C123yUgLKetxebM
CloudFormation - CREATE_IN_PROGRESS - AWS::Lambda::Version - MembersLambdaVersionN8TC7eR31v5vRUjauJUxtjhrj6n1C123yUgLKetxebM
CloudFormation - CREATE_COMPLETE - AWS::Lambda::Version - MembersLambdaVersionN8TC7eR31v5vRUjauJUxtjhrj6n1C123yUgLKetxebM
CloudFormation - UPDATE_COMPLETE_CLEANUP_IN_PROGRESS - AWS::CloudFormation::Stack - sls-aws-java-spring-cloud-function-demo-dev
CloudFormation - UPDATE_COMPLETE - AWS::CloudFormation::Stack - sls-aws-java-spring-cloud-function-demo-dev
Serverless: Stack update finished...
Service Information
service: sls-aws-java-spring-cloud-function-demo
stage: dev
region: us-east-1
stack: sls-aws-java-spring-cloud-function-demo-dev
api keys:
  None
endpoints:
  None
functions:
  members: sls-aws-java-spring-cloud-function-demo-dev-members
Stack Outputs
MembersLambdaFunctionQualifiedArn: arn:aws:lambda:us-east-1:899022498951:function:sls-aws-java-spring-cloud-function-demo-dev-members:1
ServerlessDeploymentBucketName: sls-aws-java-spring-clou-serverlessdeploymentbuck-1qadcge7s5r27

Please run following command to invoke the function

$ sls invoke -f members -l --aws-profile <your AWS profile name> --data '{"memberId":"1234567890"}'

This will invoke the function by passing the Member ID. You would see console output with response MEDICAL as below.

{
    "memberId": "1234567890",
    "coverage": "MEDICAL"
}
--------------------------------------------------------------------
START RequestId: ae39247a-7c6d-11e8-b022-eb1234c7df4f Version: $LATEST
13:58:36.347 [main] INFO org.springframework.cloud.function.adapter.aws.SpringFunctionInitializer - Initializing: class com.healthfirst.memberfunction.MemberFunctionApplication
  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::                        
2018-06-30 13:58:39.013  INFO 1 --- [           main] lambdainternal.LambdaRTEntry             : Starting LambdaRTEntry on ip-10-22-39-231.ec2.internal with PID 1 (/var/runtime/lib/LambdaJavaRTEntry-1.0.jar started by sbx_user1060 in /)
2018-06-30 13:58:39.016  INFO 1 --- [           main] lambdainternal.LambdaRTEntry             : No active profile set, falling back to default profiles: default
2018-06-30 13:58:39.297  INFO 1 --- [           main] s.c.a.AnnotationConfigApplicationContext : Refreshing org.springframework.context.annotation.AnnotationConfigApplicationContext@23fe1d71: startup date [Sat Jun 30 13:58:39 UTC 2018]; root of context hierarchy
2018-06-30 13:58:44.069  INFO 1 --- [           main] o.s.j.e.a.AnnotationMBeanExporter        : Registering beans for JMX exposure on startup
2018-06-30 13:58:44.152  INFO 1 --- [           main] lambdainternal.LambdaRTEntry             : Started LambdaRTEntry in 7.536 seconds (JVM running for 8.879)
END RequestId: ae39247a-7c6d-11e8-b022-eb1234c7df4f
REPORT RequestId: ae39247a-7c6d-11e8-b022-eb1234c7df4f  Duration: 8002.57 ms    Billed Duration: 8100 ms        Memory Size: 1024 MB    Max Memory Used: 142 MB

Please run the following command to uninstall the project from AWS

$ sls remove --aws-profile <your AWS profile name>

You would see console output something similar as

Serverless: Getting all objects in S3 bucket...
Serverless: Removing objects in S3 bucket...
Serverless: Removing Stack...
Serverless: Checking Stack removal progress...
........
Serverless: Stack removal finished...

Summary

If Java is your choice of programming language - Spring Cloud Function + Serverless Framework makes a great technology stack. It boosts developer productivity by decoupling from Vendor specific FaaS API, and deployment activities.