Introduce retry option for git push.

Jenkinsfile

@@ -40,6 +40,7 @@ pipeline {
 				PASSPHRASE = credentials('spring-gpg-passphrase')
 				KEYRING = credentials('spring-signing-secring.gpg')
 				SONATYPE = credentials('oss-login')
+				GPG_KEYNAME = credentials('spring-data-release-gpg-keyname')
 			}
 
 			steps {

src/main/java/org/springframework/data/release/TimedCommand.java

@@ -65,4 +65,35 @@ public abstract class TimedCommand implements ExecutionProcessor, CommandMarker
 		watch.stop();
 		System.out.println(String.format("Took: %.2f sec.", watch.getTotalTimeSeconds()));
 	}
+
+	/**
+	 * Means to retry commands more than once to ensure they are completed. If any exception is thrown at any time, it
+	 * will fall out and try again.
+	 *
+	 * @param action command(s) that need to be run
+	 * @param maxTimes number of times to attempt
+	 */
+	protected void retry(Runnable action, int maxTimes) {
+
+		int maxAttempts = maxTimes;
+
+		Exception lastException = null;
+
+		while (maxAttempts > 0) {
+			try {
+				action.run();
+				return;
+			} catch (Exception e) {
+				lastException = e;
+				maxAttempts--;
+			}
+		}
+
+        if (lastException != null) {
+            throw new RuntimeException(lastException);
+        } else {
+            throw new RuntimeException("Unable to complete the action within " + maxTimes + " attempts!");
+        }
+	}
+
 }

src/main/java/org/springframework/data/release/issues/github/GitHubCommands.java

@@ -61,10 +61,11 @@ public class GitHubCommands extends TimedCommand {
 	@CliCommand(value = "github push")
 	public void push(@CliOption(key = "", mandatory = true) TrainIteration iteration) {
 
-		git.push(iteration);
-		git.pushTags(iteration.getTrain());
-
-		createOrUpdateRelease(iteration);
+		retry(() -> {
+			git.push(iteration);
+			git.pushTags(iteration.getTrain());
+			createOrUpdateRelease(iteration);
+		}, 2);
 	}
 
 	@CliCommand(value = "github create release")