Amazon S3 access from Openshift Application

Openshift is DevOps platform of Red Hat. My personal idea about Openshift is that it is simple and will provide you more efficiency (for especially startups)

Openshift does't provide you a storage like S3 and in my project I need to access Amazon S3 storage from my Openshift application.

• I have an openshift application that is placed at Amazon US-East.
• I have S3 buckets under my Amazon account.

Steps, you have to apply ;
(Assumption : You have already installed rhc client for openshift.)

• Define a Group for S3 access on Amazon console.(group name : S3FullAccess)
• Go to Security Credentials part.On the right you will see the groups.
• Attach  the AmazonS3FullAccess policy to the group.
• If you don't give access you will be facing the following error 

2015-07-03 07:28:06,231 WARN  [com.amazonaws.services.s3.AmazonS3Client] (default task-1) No content length specified for stream data.  Stream contents will be buffered in memory and could result in out of memory errors.

2015-07-03 07:28:10,542 INFO  [stdout] (default task-1) Caught an AmazonServiceException, which means your request made it to Amazon S3, but was rejected with an error response for some reason.

2015-07-03 07:28:10,543 INFO  [stdout] (default task-1) Error Message:    The request signature we calculated does not match the signature you provided. Check your key and signing method. (Service: Amazon S3; Status Code: 403; Error Code: SignatureDoesNotMatch; Request ID: B424D1235CF7B2C4)

2015-07-03 07:28:10,543 INFO  [stdout] (default task-1) HTTP Status Code: 403

2015-07-03 07:28:10,544 INFO  [stdout] (default task-1) AWS Error Code:   SignatureDoesNotMatch

2015-07-03 07:28:10,544 INFO  [stdout] (default task-1) Error Type:       Client

2015-07-03 07:28:10,545 INFO  [stdout] (default task-1) Request ID:       B424D1235CF7B2C4

 

• Define a user and add it to S3FullAccess group.
• Go to recently created user and generate AWS_ACCESS_KEY and AWS_SECRET_ACCESS_KEY under security credentials part.
• Set the environment variables for AWS_ACCESS_KEY and AWS_SECRET_ACCESS_KEY
• rhc env-set AWS_ACCESS_KEY_ID='AKIAIXXXXXXHCK2Q' -a maurice
• rhc env-set AWS_SECRET_ACCESS_KEY='ETPvP3JKtXXXXXXXmsn91l+o17QJt' -a maurice
   
•  Add the following dependency for Amazon S3 objects.

         <dependency>
            <groupId>com.amazonaws</groupId>
            <artifactId>aws-java-sdk</artifactId>
            <version>1.10.2</version>
        </dependency>

• Write a servlet that will accept the posted data and write to S3 as a file.

package com.example.web.servlet;

import java.io.BufferedReader;
import java.io.ByteArrayInputStream;
import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.amazonaws.AmazonClientException;
import com.amazonaws.AmazonServiceException;
import com.amazonaws.auth.EnvironmentVariableCredentialsProvider;
import com.amazonaws.services.s3.AmazonS3;
import com.amazonaws.services.s3.AmazonS3Client;
import com.amazonaws.services.s3.model.ObjectMetadata;
import com.amazonaws.services.s3.model.PutObjectRequest;

/**
 * Servlet implementation class S3EventListener
 */
@WebServlet("/S3EventListener")
public class S3EventListener extends HttpServlet {
    private static final long serialVersionUID = 1L;
      
    /**
     * @see HttpServlet#HttpServlet()
     */
    public S3EventListener() {
        super();
        // TODO Auto-generated constructor stub
    }

    /**
     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        response.getWriter().append("Get Method is not supported.");
    }

    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        AmazonS3 s3client = new AmazonS3Client(new EnvironmentVariableCredentialsProvider());
        try {
            System.out.println("Uploading a new object to S3 from a post\n");
           
            BufferedReader reader = request.getReader();
            ByteArrayInputStream baiStream = new ByteArrayInputStream(reader.readLine().getBytes());
           
            s3client.putObject(new PutObjectRequest(
                                     "sample-bucket", "sample-file", baiStream,new ObjectMetadata() ));

         } catch (AmazonServiceException ase) {
            System.out.println("Caught an AmazonServiceException, which " +
                    "means your request made it " +
                    "to Amazon S3, but was rejected with an error response" +
                    " for some reason.");
            System.out.println("Error Message:    " + ase.getMessage());
            System.out.println("HTTP Status Code: " + ase.getStatusCode());
            System.out.println("AWS Error Code:   " + ase.getErrorCode());
            System.out.println("Error Type:       " + ase.getErrorType());
            System.out.println("Request ID:       " + ase.getRequestId());
        } catch (AmazonClientException ace) {
            System.out.println("Caught an AmazonClientException, which " +
                    "means the client encountered " +
                    "an internal error while trying to " +
                    "communicate with S3, " +
                    "such as not being able to access the network.");
            System.out.println("Error Message: " + ace.getMessage());
        }
       
       
        doGet(request, response);
    }

}


http://docs.aws.amazon.com/AWSSdkDocsJava/latest//DeveloperGuide/credentials.html