AWS Java SDK - Unable to find a region via the reg

问题:

I have gone through the question titled "Setting the AWS region programmatically 1" but it doesn't provide all the answers I need.

Q1: I'm getting a SDKClientException-Unable to find a region via the region provider chain. What am I doing wrong? or is there a typo that I missed.

public class CreateS3Bucket {

public static void main(String[] args) throws IOException {

    BasicAWSCredentials creds = new BasicAWSCredentials("aws-access-key", "aws-secret-key");
    AmazonS3 s3Client = AmazonS3ClientBuilder.standard().withCredentials(new AWSStaticCredentialsProvider(creds)).build();

    Region region = Region.getRegion(Regions.US_EAST_1);
    s3Client.setRegion(region);

    try {
        String bucketName = "testBucket" + UUID.randomUUID();
        s3Client.createBucket(bucketName);
        System.out.println("Bucket Created Successfully.");

    } catch(AmazonServiceException awse) {

        System.out.println("This means that your request made it AWS S3 but got rejected");
        System.out.println("Error Message:" +awse.getMessage());
        System.out.println("Error Message:" +awse.getErrorCode());
        System.out.println("Error Message:" +awse.getErrorType());
        System.out.println("Error Message:" +awse.getRequestId());

    } catch (AmazonClientException ace) {

        System.out.println("The Amazon Client encountered an Error with network Connectivity");
        System.out.println("Error Message:" + ace.getMessage());
    }


}

}

Q2: What code changes needs to be done if I want to build a Lambda Function out of it? I'm aware how to create a lambda function and roles that it needs. Just need to know if the code that I have written needs to changed. How should I implement the LambdaFuctionHandler class as below:

import com.amazonaws.services.lambda.runtime.Context;
import com.amazonaws.services.lambda.runtime.RequestHandler;

 public class LambdaFunctionHandler implements RequestHandler<String, String> {

@Override
public String handleRequest(String input, Context context) {
    context.getLogger().log("Input: " + input);


    return null;
}

}

回答1:

Regarding Q1, try to build your client using the following syntax:

AmazonS3 amazonS3 = AmazonS3Client.builder()
    .withRegion("us-east-1")
    .withCredentials(new AWSStaticCredentialsProvider(creds))
    .build();

回答2:

Well steps you can take to investigate:

Please make sure your Lambda function and S3 are in the same region. (When you use ProviderChain, it will pick up the region from the Lambda function

Also, You should not need to specify the BasicCredentials(aws-key..etc) if you are using Lambda.

Please read about Lambda Permission model (http://docs.aws.amazon.com/lambda/latest/dg/intro-permission-model.html):

Basically, the Lambda role that you assign should have permission to access S3.

All you need to configure S3 is pretty much:

private static final AmazonS3 s3Client = 
AmazonS3ClientBuilder.defaultClient();

To test it locally, make sure you have configured the AWS Credentials locally.

You can check if you have the credentials, if you go into .aws/credentials (This will contain the "aws-access-key", "aws-secret-key")

http://docs.aws.amazon.com/sdk-for-java/v1/developer-guide/setup-credentials.html

To set up your credentials locally, all you need to do is run the AWS Cli command: aws configure (http://docs.aws.amazon.com/cli/latest/userguide/cli-chap-getting-started.htm)

回答3:

As mentioned in the answer above you need to have S3 and lambda in same region and here's why-

If you don't explicitly set a region using the withRegion methods, the SDK consults the default region provider chain to try and determine the region to use. One of the methods used is -

The AWS_REGION environment variable is checked. If it's set, that region is used to configure the client.

And in the case of Lambda -

This environment variable is set by the Lambda container.

Finally, to use default credential/region provider chain to determine the region from the environment, use the client builder's defaultClient method.

AmazonS3 s3Client = AmazonS3ClientBuilder.defaultClient();

This is the same as using standard followed by build.

AmazonS3 s3Client = AmazonS3ClientBuilder.standard().build();

AWS Documentation: https://docs.aws.amazon.com/sdk-for-java/v1/developer-guide/java-dg-region-selection.html

More detials: How to fix "Unable to find a region via the region provider chain" exception with AWS SDK

PS: Above link goes to my personal blog that has additional details on this.

回答4:

This worked for me.

AmazonS3 s3Client = AmazonS3ClientBuilder.standard().withCredentials(new ProfileCredentialsProvider()).withRegion(Regions.AP_SOUTH_1).build();