deployment handler initial seed code

Change-Id: I0bfc86d17edead0114ea0012fb469014e978cd15
Issue-Id: DCAEGEN2-43
Signed-off-by: J. F. Lucas <jflucas@research.att.com>

1 files changed, 54 insertions, 0 deletions

diff --git a/lib/repeat.js b/lib/repeat.js
new file mode 100644
index 0000000..2ea0e14
--- /dev/null
+++ b/lib/repeat.js
@@ -0,0 +1,54 @@
+/*
+Copyright(c) 2017 AT&T Intellectual Property. All rights reserved. 
+
+Licensed under the Apache License, Version 2.0 (the "License"); 
+you may not use this file except in compliance with the License.
+
+You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, 
+software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
+CONDITIONS OF ANY KIND, either express or implied. 
+See the License for the specific language governing permissions and limitations under the License.
+*/
+
+"use strict";
+
+/**
+ * Returns a promise for running and re-running the specified action until the result meets a specific condition
+ *      - action is a function that returns a promise
+ *      - predicate is a function that takes a success result from action and returns true if the action should be rerun
+ *      - maxTries is the total number of times to try the action
+ *      - interval is the interval, in milliseconds, between tries, as approximated by setTimeout()
+ */
+
+exports.repeatWhile = function(action, predicate, maxTries, interval) {
+	return new Promise(function(resolve, reject) {
+		
+		var count = 0;
+				
+		function makeAttempt() {
+			action()
+			.then (function(res) {
+				if (!predicate(res)) {
+					// We're done
+					resolve(res);
+				}
+				else {
+					if (++count < maxTries) {
+						// set up next attempt
+						setTimeout(makeAttempt, interval);							
+					}
+					else {
+						// we've run out of retries or it's not retryable, so reject the promise
+						reject({message: "maximum repetions reached: " + count });				
+					}
+				}
+			});
+		}
+		
+		makeAttempt();
+	});
+};