Initial LRO commit

lib/lro.js

@@ -0,0 +1,112 @@
+/*
+ * Copyright 2016, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+var util = require('util');
+var NormalApiCaller = require('./api_callable').NormalApiCaller;
+var createBackoffSettings = require('.gax').createBackoffSettings;
+
+function LongrunningApicaller() {
+  NormalApiCaller.call(this);
+}
+
+util.inherits(LongrunningApicaller, NormalApiCaller);
+
+LongrunningApicaller.prototype.call = function(
+    apiCall, argument, settings, canceller) {
+  if (!settings.isLongrunning) {
+    NormalApiCaller.prototype.call.call(
+         this, apiCall, argument, settings, canceller);
+    return;
+  }
+
+  var operationsApi = settings.longrunning.operationsApi;
+
+  var backoffSettings = settings.longrunning.backoffSettings;
+  if (!backoffSettings) {
+    backoffSettings =
+        createBackoffSettings(100, 1.3, 60000, null, null, null, 600000);
+  }
+
+  var delayMult = backoffSettings.retryDelayMultiplier;
+  var maxDelay = backoffSettings.maxRetryDelayMillis;
+  var delay = backoffSettings.initialRetryDelayMillis;
+  var now = new Date();
+  var deadline = now.getTime() + backoffSettings.totalTimeoutMillis;
+
+  function retryOperation(op) {
+    if (op.done) {
+      var error;
+      if (op.result.hasError) {
+        error = new Error(op.result.error.message);
+        error.code = op.result.error.code;
+        canceller.callback(error);
+        return;
+      }
+      canceller.callback(null, op.result.response);
+    }
+
+    if (now.getTime() >= deadline) {
+      canceller.callback(new Error('Total timeout exceeded before any' +
+          'response was received'));
+      return;
+    }
+
+    var toSleep = Math.random() * delay;
+    setTimeout(function() {
+      now = new Date();
+      delay = Math.min(delay * delayMult, maxDelay);
+      operationsApi.getOperation({name: op.name}).then(function(operation) {
+        retryOperation(operation);
+      });
+    }, toSleep);
+  }
+
+  apiCall(argument, function(err, response) {
+    if (err) {
+      canceller.callback(err);
+      return;
+    }
+    retryOperation(response);
+  });
+};
+
+/**
+ * Describes the structure of a longrunning call.
+ * @constructor
+ */
+function LongrunningDescriptor() {
+}
+
+LongrunningDescriptor.prototype.apiCaller = function() {
+  return new LongrunningApicaller(this);
+};
+
+exports.LongrunningDescriptor = LongrunningDescriptor;