Fixes issue where environment variable value overwrites the value in AWS CodeDeploy Deployment Group field.

When executing a build, if an environemnt variable is specified by name in the AWS CodeDeploy Deployment Group field, at the end of the build the value of the environment variable will ovewrite the name of the environment variable in that field.

Example of the bug this commit fixes:
At the start of a build, the value of AWS CodeDeploy Deployment Group is "$DEPLOYMENT_GROUP". I then do a build where the value of the $DEPLOYMENT_GROUP environment variable is "QA". If I wait until the end of the build and come back to the Configure page, the value of the field will now be "QA".

Author: cojennin

src/main/java/com/amazonaws/codedeploy/AWSCodeDeployPublisher.java

@@ -82,7 +82,7 @@ public class AWSCodeDeployPublisher extends Publisher {
     private final String  s3bucket;
     private final String  s3prefix;
     private final String  applicationName;
-    private       String  deploymentGroupName; // TODO allow for deployment to multiple groups
+    private final String  deploymentGroupName; // TODO allow for deployment to multiple groups
     private final String  deploymentConfig;
     private final Long    pollingTimeoutSec;
     private final Long    pollingFreqSec;
@@ -214,15 +214,15 @@ public boolean perform(AbstractBuild build, Launcher launcher, BuildListener lis
         try {
 
             Map<String, String> envVars = build.getEnvironment(listener);
-            this.deploymentGroupName = Util.replaceMacro(this.deploymentGroupName, envVars);
+            String deploymentGroupName = Util.replaceMacro(this.deploymentGroupName, envVars);
 
-            verifyCodeDeployApplication(aws);
+            verifyCodeDeployApplication(aws, deploymentGroupName);
 
             String projectName = build.getProject().getName();
-            RevisionLocation revisionLocation = zipAndUpload(aws, projectName, getSourceDirectory(build.getWorkspace()), envVars);
+            RevisionLocation revisionLocation = zipAndUpload(aws, projectName, getSourceDirectory(build.getWorkspace()), envVars, deploymentGroupName);
 
             registerRevision(aws, revisionLocation);
-            String deploymentId = createDeployment(aws, revisionLocation);
+            String deploymentId = createDeployment(aws, revisionLocation, deploymentGroupName);
 
             success = waitForDeployment(aws, deploymentId);
 
@@ -262,7 +262,7 @@ private boolean isSubDirectory(FilePath parent, FilePath child) {
         return false;
     }
 
-    private void verifyCodeDeployApplication(AWSClients aws) throws IllegalArgumentException {
+    private void verifyCodeDeployApplication(AWSClients aws, String deploymentGroupName) throws IllegalArgumentException {
         // Check that the application exists
         ListApplicationsResult applications = aws.codedeploy.listApplications();
 
@@ -276,27 +276,27 @@ private void verifyCodeDeployApplication(AWSClients aws) throws IllegalArgumentE
                         .withApplicationName(this.applicationName)
         );
 
-        if (!deploymentGroups.getDeploymentGroups().contains(this.deploymentGroupName)) {
-            throw new IllegalArgumentException("Cannot find deployment group named '" + this.deploymentGroupName + "'");
+        if (!deploymentGroups.getDeploymentGroups().contains(deploymentGroupName)) {
+            throw new IllegalArgumentException("Cannot find deployment group named '" + deploymentGroupName + "'");
         }
     }
 
-    private RevisionLocation zipAndUpload(AWSClients aws, String projectName, FilePath sourceDirectory, Map<String, String> envVars) throws IOException, InterruptedException, IllegalArgumentException {
+    private RevisionLocation zipAndUpload(AWSClients aws, String projectName, FilePath sourceDirectory, Map<String, String> envVars, String deploymentGroupName) throws IOException, InterruptedException, IllegalArgumentException {
 
         File zipFile = File.createTempFile(projectName + "-", ".zip");
         String key;
         File appspec;
         File dest;
         try {
             if (this.deploymentGroupAppspec) {
-                appspec = new File(sourceDirectory + "/appspec." + this.deploymentGroupName + ".yml");
+                appspec = new File(sourceDirectory + "/appspec." + deploymentGroupName + ".yml");
                 if (appspec.exists()) {
                     dest = new File(sourceDirectory + "/appspec.yml");
                     FileUtils.copyFile(appspec, dest);
-                    logger.println("Use appspec." + this.deploymentGroupName + ".yml");
+                    logger.println("Use appspec." + deploymentGroupName + ".yml");
                 }
                 if (!appspec.exists()) {
-                    throw new IllegalArgumentException("/appspec." + this.deploymentGroupName + ".yml file does not exist" );
+                    throw new IllegalArgumentException("/appspec." + deploymentGroupName + ".yml file does not exist" );
                 }
 
             }
@@ -352,14 +352,14 @@ private void registerRevision(AWSClients aws, RevisionLocation revisionLocation)
         );
     }
 
-    private String createDeployment(AWSClients aws, RevisionLocation revisionLocation) throws Exception {
+    private String createDeployment(AWSClients aws, RevisionLocation revisionLocation, String deploymentGroupName) throws Exception {
 
         this.logger.println("Creating deployment with revision at " + revisionLocation);
 
         CreateDeploymentResult createDeploymentResult = aws.codedeploy.createDeployment(
                 new CreateDeploymentRequest()
                         .withDeploymentConfigName(this.deploymentConfig)
-                        .withDeploymentGroupName(this.deploymentGroupName)
+                        .withDeploymentGroupName(deploymentGroupName)
                         .withApplicationName(this.applicationName)
                         .withRevision(revisionLocation)
                         .withDescription("Deployment created by Jenkins")