CODEWITHSUNDEEP
aws-lambdaaws-sdk
Ashu
Ashu

Reputation: 75

Invoke AWS Lambda function from AWS java SDK

enter image description here Is it possible to invoke aws lambda function from the aws publish subscribe sample java code? Can we invoke lambda function from our java code? if yes then how?

Upvotes: 1

Views: 4058

Answers (1)

Yoko Zunna
Yoko Zunna

Reputation: 1824

Invoking an AWS Lambda Function from Java

import com.amazonaws.regions.Regions;
import com.amazonaws.services.lambda.AWSLambda;
import com.amazonaws.services.lambda.AWSLambdaClientBuilder;
import com.amazonaws.services.lambda.model.InvokeRequest;
import com.amazonaws.services.lambda.model.InvokeResult;
// ...
// (1) Define the AWS Region in which the function is to be invoked
Regions region = Regions.fromName("us-east-1");
// (2) Instantiate AWSLambdaClientBuilder to build the Lambda client
AWSLambdaClientBuilder builder = AWSLambdaClientBuilder.standard()
                                    .withRegion(region);
// (3) Build the client, which will ultimately invoke the function
AWSLambda client = builder.build();
// (4) Create an InvokeRequest with required parameters
InvokeRequest req = new InvokeRequest()
                           .withFunctionName("myFunctionName")
                           .withPayload("{ ... }"); // optional
// (5) Invoke the function and capture response
InvokeResult result = client.invoke(req);
// (6) Handle result
...

The above will invoke Lambda synchronously; however, you can also invoke asynchronously using Java Futures or callbacks.

Invocation with Access Key and Secret Key The above sample will utilize the DefaultAWSCredentialsProviderChain to utilize environment variables, EC2 Instance Profile, etc. when invoking the function. While this is often best practice, there are also scenarios when you may need to provide access and secret keys. To do so, we only need to make a small change to the code above:

import com.amazonaws.auth.AWSStaticCredentialsProvider;
import com.amazonaws.auth.BasicAWSCredentials;
// (1a) Instantiate credentials
BasicAWSCredentials credentials = new 
  BasicAWSCredentials("myAccessKey", "mySecretKey");
// (2) Modify to leverage credentials
AWSLambdaClientBuilder builder = AWSLambdaClientBuilder.standard()
  .withCredentials(new AWSStaticCredentialsProvider(credentials));                                     
  .withRegion(region);

Upvotes: 2

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