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authorlj1412 <lji@research.att.com>2017-02-14 15:10:25 +0000
committerlj1412 <lji@research.att.com>2017-02-14 15:10:27 +0000
commitf2ec39706a7a31017f5d219c44d54d40714d9a27 (patch)
tree0442ccf8420a388d264cca3bc4965a0c1035af0d /lib/repeat.js
parentd53e0cf57fc289259b6c9de5bfad224f23cd2988 (diff)
Init dcae.orch-dispatcher
Change-Id: I52aa696bd5d1d5ed3bc6e03a3c994dc0b3a71062 Signed-off-by: lj1412 <lji@research.att.com>
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+/*
+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();
+ });
+};