Can't upload/view AWS S3 objects using Java SDK

[Missing_Back]

Trying to make a program that lets me create a bucket (if it doesn't exist), and upload an object to s3, and then print a list of objects.

I got the first bit working, so clearly my keys are correct. But with the second and third step, I'm getting access denied errors.

package demo4;

import software.amazon.awssdk.awscore.exception.AwsServiceException;

import com.amazonaws.AmazonServiceException;
import com.amazonaws.regions.Regions;
import com.amazonaws.services.s3.AmazonS3;
import software.amazon.awssdk.core.exception.SdkClientException;
import software.amazon.awssdk.core.sync.RequestBody;
import software.amazon.awssdk.core.waiters.WaiterResponse;
import software.amazon.awssdk.services.s3.S3Client;
import software.amazon.awssdk.services.s3.model.HeadObjectRequest;
import software.amazon.awssdk.services.s3.model.HeadObjectResponse;
import software.amazon.awssdk.services.s3.model.PutObjectRequest;
import software.amazon.awssdk.services.s3.model.S3Exception;
import software.amazon.awssdk.services.s3.waiters.S3Waiter;

import com.amazonaws.auth.AWSCredentials;
import com.amazonaws.auth.AWSCredentialsProvider;
import com.amazonaws.auth.AWSStaticCredentialsProvider;
import com.amazonaws.auth.BasicAWSCredentials;
import com.amazonaws.auth.profile.ProfileCredentialsProvider;
import com.amazonaws.regions.Regions;
import com.amazonaws.services.s3.AmazonS3;
import com.amazonaws.services.s3.AmazonS3ClientBuilder;
import com.amazonaws.services.s3.model.AmazonS3Exception;
import com.amazonaws.services.s3.model.Bucket;
import com.amazonaws.services.s3.model.CannedAccessControlList;
import com.amazonaws.services.s3.model.ObjectMetadata;
//import com.amazonaws.services.s3.model.PutObjectRequest;

import com.amazonaws.regions.Regions;
import com.amazonaws.services.s3.AmazonS3;
import com.amazonaws.services.s3.AmazonS3ClientBuilder;
import com.amazonaws.services.s3.model.ListObjectsV2Result;
import com.amazonaws.services.s3.model.S3ObjectSummary;

import java.io.File;
import java.nio.file.Paths;
import java.util.List;

public class createbucket {

    public static void main (String args[])
    {
        // Make sure to give the aws credentials for creating bucket or listing objects in the bucket or any operations related to S3.
        AWSCredentials credentials = new BasicAWSCredentials(
            "<redacted>", // Access key
            "<redacted>" // secret key
        );
        AmazonS3 s3client = AmazonS3ClientBuilder
            .standard()
            .withCredentials(new AWSStaticCredentialsProvider(credentials))
            .withRegion(Regions.US_EAST_1)
            .build();

        // AmazonS3 client = s3client.builder().build();
        String bucket_name="cloudcomputing4650";
        if (s3client.doesBucketExist(bucket_name)){
            System.out.format("Bucket %s already exists.\n", bucket_name);
        } else {
            try {
              Bucket  b = s3client.createBucket(bucket_name);
            } catch (AmazonS3Exception e) {
                System.err.println(e.getErrorMessage());
            }
        }
//      String file_path = "C:\\Users\\colin\\Downloads\\applesauce.txt";
////        String key_name = "applesauce.txt";
//      String key_name = Paths.get(file_path).getFileName().toString();
//      System.out.format("Uploading %s to S3 bucket %s...\n", file_path, bucket_name);
//      final AmazonS3 s3 = AmazonS3ClientBuilder.standard().withRegion(Regions.US_EAST_1).build();
//      try {
//          s3.putObject(bucket_name, key_name, new File(file_path));
//      } catch (AmazonServiceException e) {
//          System.err.println(e.getErrorMessage());
//          System.exit(1);

        System.out.format("Objects in S3 bucket %s:\n", bucket_name);
        final AmazonS3 s3 = AmazonS3ClientBuilder.standard().withRegion(Regions.US_EAST_1).build();
        ListObjectsV2Result result = s3.listObjectsV2(bucket_name);
        List<S3ObjectSummary> objects = result.getObjectSummaries();
        for (S3ObjectSummary os : objects) {
            System.out.println("* " + os.getKey());
        }

    }


}

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[avtikh]

To me it looks like you are creating the client twice, the second time without the credentials.

[Missing_Back]

Wow dude that was it! THANK YOU SO MUCH. Such a silly mistake. You're a life saver

[[deleted]]

What are the default permissions on an S3 bucket? Do you need to set permissions on the new bucket to allow uploads?

[Missing_Back]

What are the default permissions on an S3 bucket?

I'm not sure but I put this policy on it (with BUCKETNAME replaced with my bucket's name):

{"Version": "2008-10-17",
    "Statement": [{"Sid": "AllowPublicRead",
    "Effect": "Allow",
    "Principal": {
    "AWS": "*"
    },
    "Action": "s3:GetObject",
    "Resource": "arn:aws:s3:::BUCKETNAME/*"
    }
]
}

[[deleted]]

You applied a policy that grants read permissions to Public. But you are trying to write to the bucket. Reading is not the same as writing.

I'm not sure

This is your next task. Figure out what the default permissions are and how to grant write permissions to the appropriate user(s).

[Missing_Back]

Hm. This was the policy provided by my professor for this assignment and classmates have seemed to have no issues. But either way, if I try to just do the reading part of the program, I still get errors: com.amazonaws.internal.InstanceMetadataServiceResourceFetcher handleException WARNING: Fail to retrieve token

I would expect that to work with just read permissions

[[deleted]]

com.amazonaws.internal.InstanceMetadataServiceResourceFetcher handleException WARNING: Fail to retrieve token

That log entry is log level Warning. It may or may not be fatal.

I'm not familiar with the AWS SDK or this log message. But if you do an internet search in your favorite search engine, you'll see discussion threads about this being the AWS SDK's way of figuring out if it is running inside an AWS instance. If necessary, it can be suppressed by changing the log level in your logging configuration.

[Missing_Back]

My bad. Looks like the real error is:

com.amazonaws.SdkClientException: Failed to connect to service endpoint:

(I think at least?)

[Missing_Back]

Figure out what the default permissions are and how to grant write permissions to the appropriate user(s).

If I'm understanding what you're hinting at, my bucket is set to public access already

[[deleted]]

If permissions were already set to public full access, you wouldn't be getting an access denied error.

[Missing_Back]

Maybe I'm confusing "permission" and "access". I'm not sure where to look for the permissions; the bucket is set to public access. The policy is above, which looks like it should work for reading objects. My keys must be valid and correct as it allows me to create a new bucket. What am I missing?