AWS Java SDK - Unable to find a region via the region provider chain

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;
}


}
107314 次浏览
小开

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)

小开
最佳答案

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

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

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 details: 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.

小开

This worked for me.

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

You can try this as below

BasicAWSCredentials creds = new BasicAWSCredentials("your-accessKey", "your-secretKey");
AmazonSNS snsClient = AmazonSNSClientBuilder.standard()
.withCredentials(new AWSStaticCredentialsProvider(creds))
.withRegion(Regions.US_EAST_1).build();
小开

Actually, while I faced this issue was not possible to update the code all the time.

Thus we need to look into the reasons why it's happening, While investigating I found there is .aws folder created at your root. It was created because I tried to install aws console some time back.

The solution is you need to update your config file with region.

小开

withRegion(Regions.DEFAULT_REGION) helped me to solve my issue

return AmazonS3ClientBuilder.standard()
.withCredentials(new AWSStaticCredentialsProvider(awsCredentials))
.withRegion(Regions.DEFAULT_REGION)
.build();
小开

You can set the region in the environment of AWS for your session.

If you are on Windows, add in c:\user\%USERNAME%\.aws\config the next text:

[default]
region = us-east-1
output = json

That works for me.

小开

So, root cause of the issue is the AmazonS3 needs to know the region to connect to for doing any operations on S3 bucket.

In my case, credentials not needed as it was handled via IAM roles on the server from where the operation was being performed.

But still the initialisation of the amazoneS3Client was failing with the error while injecting the bean defined in my class

private final AmazonS3 amazonS3Client;

And the spring application fails to load the context as the bean cannot be created. BeanCreation of AmazonS3 fails with below root cause

Failed to instantiate [com.amazonaws.services.s3.AmazonS3]:
Factory method 'amazonS3Client' threw exception; nested exception is com.amazonaws.SdkClientException:
Unable to find a region via the region provider chain.
Must provide an explicit region in the builder or setup environment to supply a region.

So, the fix for that is to configure the region while creating the bean.

@Bean
AmazonS3 amazonS3Client() {
return AmazonS3ClientBuilder.standard().withRegion(s3ConfigProperties.getRegion()).build();
}

As you see, we are passing the region in .withRegion(), and this region is defined in the application.yml file.

 region: 'eu-west-1'

提交答案