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common: add Operation object
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-378
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6 files changed

+598
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‎packages/common/src/grpc-operation.js

+6-91
Original file line numberDiff line numberDiff line change
@@ -20,20 +20,19 @@
2020

2121
'use strict';
2222

23-
var events = require('events');
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var modelo = require('modelo');
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/**
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* @type {module:common/grpcService}
26+
* @type {module:common/grpcServiceObject}
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* @private
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*/
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var GrpcService = require('./grpc-service.js');
29+
var GrpcServiceObject = require('./grpc-service-object.js');
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/**
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* @type {module:common/grpcServiceObject}
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* @type {module:common/operation}
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* @private
3534
*/
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var GrpcServiceObject = require('./grpc-service-object.js');
35+
var Operation = require('./operation.js');
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/**
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* @type {module:common/util}
@@ -101,16 +100,11 @@ function GrpcOperation(parent, name) {
101100
methods: methods
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};
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Operation.call(this, config);
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GrpcServiceObject.call(this, config);
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events.EventEmitter.call(this);
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this.completeListeners = 0;
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this.hasActiveListeners = false;
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this.listenForEvents_();
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}
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modelo.inherits(GrpcOperation, GrpcServiceObject, events.EventEmitter);
107+
modelo.inherits(GrpcOperation, GrpcServiceObject, Operation);
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/**
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* Cancel the operation.
@@ -133,83 +127,4 @@ GrpcOperation.prototype.cancel = function(callback) {
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this.request(protoOpts, reqOpts, callback || util.noop);
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};
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/**
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* Wraps the `complete` and `error` events in a Promise.
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*
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* @return {promise}
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*/
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GrpcOperation.prototype.promise = function() {
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var self = this;
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return new self.Promise(function(resolve, reject) {
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self
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.on('error', reject)
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.on('complete', function(metadata) {
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resolve([metadata]);
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});
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});
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};
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/**
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* Begin listening for events on the operation. This method keeps track of how
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* many "complete" listeners are registered and removed, making sure polling is
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* handled automatically.
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*
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* As long as there is one active "complete" listener, the connection is open.
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* When there are no more listeners, the polling stops.
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*
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* @private
162-
*/
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GrpcOperation.prototype.listenForEvents_ = function() {
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var self = this;
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this.on('newListener', function(event) {
167-
if (event === 'complete') {
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self.completeListeners++;
169-
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if (!self.hasActiveListeners) {
171-
self.hasActiveListeners = true;
172-
self.startPolling_();
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}
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}
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});
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this.on('removeListener', function(event) {
178-
if (event === 'complete' && --self.completeListeners === 0) {
179-
self.hasActiveListeners = false;
180-
}
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});
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};
183-
184-
/**
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* Poll `getMetadata` to check the operation's status. This runs a loop to ping
186-
* the API on an interval.
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*
188-
* Note: This method is automatically called once a "complete" event handler is
189-
* registered on the operation.
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*
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* @private
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*/
193-
GrpcOperation.prototype.startPolling_ = function() {
194-
var self = this;
195-
196-
if (!this.hasActiveListeners) {
197-
return;
198-
}
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this.getMetadata(function(err, resp) {
201-
if (err || resp.error) {
202-
self.emit('error', err || GrpcService.decorateStatus_(resp.result));
203-
return;
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}
205-
206-
if (!resp.done) {
207-
setTimeout(self.startPolling_.bind(self), 500);
208-
return;
209-
}
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self.emit('complete', resp);
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});
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};
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215130
module.exports = GrpcOperation;

‎packages/common/src/index.js

+6
Original file line numberDiff line numberDiff line change
@@ -32,6 +32,12 @@ exports.GrpcService = require('./grpc-service.js');
3232
*/
3333
exports.GrpcServiceObject = require('./grpc-service-object.js');
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35+
/**
36+
* @type {module:common/operation}
37+
* @private
38+
*/
39+
exports.Operation = require('./operation.js');
40+
3541
/**
3642
* @type {module:common/paginator}
3743
* @private

‎packages/common/src/operation.js

+198
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,198 @@
1+
/*!
2+
* Copyright 2016 Google Inc. All Rights Reserved.
3+
*
4+
* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
6+
* You may obtain a copy of the License at
7+
*
8+
* http://www.apache.org/licenses/LICENSE-2.0
9+
*
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* Unless required by applicable law or agreed to in writing, software
11+
* distributed under the License is distributed on an "AS IS" BASIS,
12+
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13+
* See the License for the specific language governing permissions and
14+
* limitations under the License.
15+
*/
16+
17+
/*!
18+
* @module common/operation
19+
*/
20+
21+
'use strict';
22+
23+
var events = require('events');
24+
var extend = require('extend');
25+
var modelo = require('modelo');
26+
27+
/**
28+
* @type {module:common/service}
29+
* @private
30+
*/
31+
var GrpcService = require('./grpc-service.js');
32+
33+
/**
34+
* @type {module:common/serviceObject}
35+
* @private
36+
*/
37+
var ServiceObject = require('./service-object.js');
38+
39+
// jscs:disable maximumLineLength
40+
/**
41+
* An Operation object allows you to interact with APIs that take longer to
42+
* process things.
43+
*
44+
* @constructor
45+
* @alias module:common/operation
46+
*
47+
* @param {object} config - Configuration object.
48+
* @param {module:common/service|module:common/serviceObject|module:common/grpcService|module:common/grpcServiceObject} config.parent - The
49+
* parent object.
50+
* @param {string} id - The operation ID.
51+
*/
52+
// jscs:enable maximumLineLength
53+
function Operation(config) {
54+
var methods = {
55+
/**
56+
* Checks to see if an operation exists.
57+
*/
58+
exists: true,
59+
60+
/**
61+
* Retrieves the operation.
62+
*/
63+
get: true,
64+
65+
/**
66+
* Retrieves metadata for the operation.
67+
*/
68+
getMetadata: {
69+
reqOpts: {
70+
name: config.id
71+
}
72+
}
73+
};
74+
75+
config = extend({
76+
baseUrl: ''
77+
}, config);
78+
79+
config.methods = config.methods || methods;
80+
81+
ServiceObject.call(this, config);
82+
events.EventEmitter.call(this);
83+
84+
this.completeListeners = 0;
85+
this.hasActiveListeners = false;
86+
87+
this.listenForEvents_();
88+
}
89+
90+
modelo.inherits(Operation, ServiceObject, events.EventEmitter);
91+
92+
/**
93+
* Wraps the `complete` and `error` events in a Promise.
94+
*
95+
* @return {promise}
96+
*/
97+
Operation.prototype.promise = function() {
98+
var self = this;
99+
100+
return new self.Promise(function(resolve, reject) {
101+
self
102+
.on('error', reject)
103+
.on('complete', function(metadata) {
104+
resolve([metadata]);
105+
});
106+
});
107+
};
108+
109+
/**
110+
* Begin listening for events on the operation. This method keeps track of how
111+
* many "complete" listeners are registered and removed, making sure polling is
112+
* handled automatically.
113+
*
114+
* As long as there is one active "complete" listener, the connection is open.
115+
* When there are no more listeners, the polling stops.
116+
*
117+
* @private
118+
*/
119+
Operation.prototype.listenForEvents_ = function() {
120+
var self = this;
121+
122+
this.on('newListener', function(event) {
123+
if (event === 'complete') {
124+
self.completeListeners++;
125+
126+
if (!self.hasActiveListeners) {
127+
self.hasActiveListeners = true;
128+
self.startPolling_();
129+
}
130+
}
131+
});
132+
133+
this.on('removeListener', function(event) {
134+
if (event === 'complete' && --self.completeListeners === 0) {
135+
self.hasActiveListeners = false;
136+
}
137+
});
138+
};
139+
140+
/**
141+
* Poll for a status update. Execute the callback:
142+
*
143+
* - callback(err): Operation failed
144+
* - callback(): Operation incomplete
145+
* - callback(null, metadata): Operation complete
146+
*
147+
* @private
148+
*
149+
* @param {function} callback
150+
*/
151+
Operation.prototype.poll_ = function(callback) {
152+
this.getMetadata(function(err, resp) {
153+
if (err || resp.error) {
154+
callback(err || GrpcService.decorateGrpcStatus_(resp.error));
155+
return;
156+
}
157+
158+
if (!resp.done) {
159+
callback();
160+
return;
161+
}
162+
163+
callback(null, resp);
164+
});
165+
};
166+
167+
/**
168+
* Poll `getMetadata` to check the operation's status. This runs a loop to ping
169+
* the API on an interval.
170+
*
171+
* Note: This method is automatically called once a "complete" event handler is
172+
* registered on the operation.
173+
*
174+
* @private
175+
*/
176+
Operation.prototype.startPolling_ = function() {
177+
var self = this;
178+
179+
if (!this.hasActiveListeners) {
180+
return;
181+
}
182+
183+
this.poll_(function(err, metadata) {
184+
if (err) {
185+
self.emit('error', err);
186+
return;
187+
}
188+
189+
if (!metadata) {
190+
setTimeout(self.startPolling_.bind(self), 500);
191+
return;
192+
}
193+
194+
self.emit('complete', metadata);
195+
});
196+
};
197+
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module.exports = Operation;

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