[JENKINS-25933] Improve errors when credentials are missing or miscon…

…figured.

src/main/java/org/jenkinsci/plugins/googleplayandroidpublisher/ApkUploadTask.java

@@ -96,7 +96,7 @@ protected Boolean execute() throws IOException, InterruptedException, UploadExce
             // Check whether this APK already exists on the server (i.e. uploading it would fail)
             for (Apk apk : existingApks) {
                 if (apk.getBinary().getSha1().toLowerCase(Locale.ENGLISH).equals(apkSha1Hash)) {
-                    logger.println("This APK already exists on the server; it cannot be uploaded again");
+                    logger.println("This APK already exists in the Google Play account; it cannot be uploaded again");
                     return false;
                 }
             }

src/main/java/org/jenkinsci/plugins/googleplayandroidpublisher/CredentialsException.java

@@ -0,0 +1,10 @@
+package org.jenkinsci.plugins.googleplayandroidpublisher;
+
+/** Thrown when there's a local configuration error with the Google Play credentials. */
+public class CredentialsException extends UploadException {
+
+    public CredentialsException(String message) {
+        super(message);
+    }
+
+}

src/main/java/org/jenkinsci/plugins/googleplayandroidpublisher/CredentialsHandler.java

@@ -2,17 +2,25 @@
 
 import com.google.jenkins.plugins.credentials.oauth.GoogleOAuth2ScopeRequirement;
 import com.google.jenkins.plugins.credentials.oauth.GoogleRobotCredentials;
+import com.google.jenkins.plugins.credentials.oauth.GoogleRobotPrivateKeyCredentials;
 import org.apache.commons.lang.exception.ExceptionUtils;
 
 import java.io.FileNotFoundException;
 import java.security.GeneralSecurityException;
 
+import static hudson.Util.fixEmptyAndTrim;
+
 public class CredentialsHandler {
 
     private final String googleCredentialsId;
 
-    public CredentialsHandler(String googleCredentialsId) {
-        this.googleCredentialsId = googleCredentialsId;
+    public CredentialsHandler(String googleCredentialsId) throws CredentialsException {
+        String id = fixEmptyAndTrim(googleCredentialsId);
+        if (id == null) {
+            throw new CredentialsException("No credentials have been specified: You must add a Google Account via the "
+                    + "Jenkins Credentials page, then configure this job to use those credentials");
+        }
+        this.googleCredentialsId = id;
     }
 
     /** @return The Google API credentials configured for this job. */
@@ -21,15 +29,25 @@ public final GoogleRobotCredentials getServiceAccountCredentials() throws Upload
             GoogleOAuth2ScopeRequirement req = new AndroidPublisherScopeRequirement();
             GoogleRobotCredentials credentials = GoogleRobotCredentials.getById(googleCredentialsId);
             if (credentials == null) {
-                throw new UploadException("Credentials for the configured Google Account could not be found");
+                throw new CredentialsException(String.format("The configured Google Service Account credential '%s' "
+                        + "could not be found.\n\tIf you renamed the credential since configuring this job, you must "
+                        + "re-configure this job, choosing the new credential name", googleCredentialsId));
             }
             return credentials.forRemote(req);
+        } catch (GoogleRobotPrivateKeyCredentials.AccountIdNotSetException e) {
+            throw new CredentialsException(String.format("The configured Google Service Account credential '%s' "
+                    + "has not been configured correctly.\n\tUpdate the credential, ensuring that the required data "
+                    + "have been entered and try again", googleCredentialsId));
+        } catch (GoogleRobotPrivateKeyCredentials.PrivateKeyNotSetException e) {
+            throw new CredentialsException(String.format("The configured Google Service Account credential '%s' "
+                    + "has not been configured correctly.\n\tUpdate the credential, ensuring that the required data "
+                    + "have been entered and try again", googleCredentialsId));
         } catch (NullPointerException e) {
             // This should really be handled by the Google OAuth plugin
             throw new UploadException("Failed to get Google service account info.\n" +
                     "\tCheck that the correct 'Client Secrets JSON' file has been uploaded for the " +
-                    "'"+ googleCredentialsId +"' credential.\n" +
-                    "\tThe correct JSON file can be obtained by visiting the *old* Google APIs Console, selecting "+
+                    "'" + googleCredentialsId + "' credential.\n" +
+                    "\tThe correct JSON file can be obtained by visiting the *old* Google APIs Console, selecting " +
                     "'API Access' and then clicking 'Download JSON' for the appropriate service account.\n" +
                     "\tSee: https://code.google.com/apis/console/?noredirect", e);
         } catch (IllegalStateException e) {

src/main/java/org/jenkinsci/plugins/googleplayandroidpublisher/GooglePlayBuilder.java

@@ -13,7 +13,7 @@
     @DataBoundSetter
     private String googleCredentialsId;
 
-    protected CredentialsHandler getCredentialsHandler() {
+    protected CredentialsHandler getCredentialsHandler() throws CredentialsException {
         if (credentialsHandler == null) {
             credentialsHandler = new CredentialsHandler(googleCredentialsId);
         }

src/main/java/org/jenkinsci/plugins/googleplayandroidpublisher/GooglePlayPublisher.java

@@ -13,7 +13,7 @@
     @DataBoundSetter
     private String googleCredentialsId;
 
-    protected CredentialsHandler getCredentialsHandler() {
+    protected CredentialsHandler getCredentialsHandler() throws CredentialsException {
         if (credentialsHandler == null) {
             credentialsHandler = new CredentialsHandler(googleCredentialsId);
         }

src/main/java/org/jenkinsci/plugins/googleplayandroidpublisher/Util.java

@@ -75,6 +75,9 @@ static String expand(EnvVars env, String value) {
 
     /** @return A user-friendly(ish) Google Play API error message, if one could be found in the given exception. */
     static String getPublisherErrorMessage(UploadException e) {
+        if (e instanceof CredentialsException) {
+            return e.getMessage();
+        }
         if (e instanceof PublisherApiException) {
             // TODO: Here we could map error reasons like "apkUpgradeVersionConflict" to better (and localised) text
             String message = ((PublisherApiException) e).getDetailsMessage();