AWS Java SDK - Get EC2 instance info - amazon-web-services

Question

Given an instance id, I want to get an EC2 instance info (for example, its running status, private IP, public IP).
I have done some research (i.e. looking at the sample code posted here Managing Amazon EC2 Instances)
but there is only sample code of getting the Amazon EC2 instances for your account and region.
I tried to modify the sample and here is what I came up with:
private static AmazonEC2 getEc2StandardClient() {
// Using StaticCredentialsProvider
final String accessKey = "access_key";
final String secretKey = "secret_key";
BasicAWSCredentials credentials = new BasicAWSCredentials(accessKey, secretKey);
return AmazonEC2ClientBuilder.standard()
.withRegion(Regions.AP_NORTHEAST_1)
.withCredentials(new AWSStaticCredentialsProvider(credentials))
.build();
}
public static void getInstanceInfo(String instanceId) {
final AmazonEC2 ec2 = getEc2StandardClient();
DryRunSupportedRequest<DescribeInstancesRequest> dryRequest =
() -> {
DescribeInstancesRequest request = new DescribeInstancesRequest()
.withInstanceIds(instanceId);
return request.getDryRunRequest();
};
DryRunResult<DescribeInstancesRequest> dryResponse = ec2.dryRun(dryRequest);
if(!dryResponse.isSuccessful()) {
System.out.println("Failed to get information of instance " + instanceId);
}
DescribeInstancesRequest request = new DescribeInstancesRequest()
.withInstanceIds(instanceId);
DescribeInstancesResult response = ec2.describeInstances(request);
Reservation reservation = response.getReservations().get(0);
Instance instance = reservation.getInstances().get(0);
System.out.println("Instance id: " + instance.getInstanceId(), ", state: " + instance.getState().getName() +
", public ip: " + instance.getPublicIpAddress() + ", private ip: " + instance.getPrivateIpAddress());
}
It is working fine but I wonder if it's the best practice to get info from a single instance.

Answer 1

but there is only sample code of getting the Amazon EC2 instances for your account and region.
Yes, you may get only instance information you have permission to read.
It is working fine but I wonder if it's the best practice to get info from a single instance
You have multiple options.
For getting EC2 metadata from any client (e.g. from your on-premise network) your code seems ok.
If you are running the code in the AWS environment (on an EC2, lambda, docker, ..) you may specify a service role allowed calling the describeInstances operation from the service. Then you don't need to specify the AWS credentials explicitly (DefaultAWSCredentialsProviderChain will work).
If you are getting the EC2 metadata from the instance itself, you can use the EC2 metadata service.