introduce common-gax

packages/common-gax/package.json

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+{
+  "name": "@google-cloud/common-gax",
+  "version": "0.0.0",
+  "author": "Google Inc.",
+  "description": "Common components for Cloud APIs Node.js Client Libraries that require google-gax",
+  "contributors": [
+    {
+      "name": "Stephen Sawchuk",
+      "email": "sawchuk@gmail.com"
+    }
+  ],
+  "main": "./src/index.js",
+  "files": [
+    "src",
+    "AUTHORS",
+    "CONTRIBUTORS",
+    "COPYING"
+  ],
+  "repository": "googlecloudplatform/google-cloud-node",
+  "dependencies": {
+    "@google-cloud/common": "^0.13.1",
+    "extend": "^3.0.0",
+    "stream-events": "^1.0.1",
+    "through2": "^2.0.3"
+  },
+  "devDependencies": {
+    "mocha": "^3.2.0",
+    "proxyquire": "^1.7.10"
+  },
+  "scripts": {
+    "publish-module": "node ../../scripts/publish.js common-gax",
+    "test": "mocha test/*.js"
+  },
+  "license": "Apache-2.0",
+  "engines": {
+    "node": ">=4.0.0"
+  }
+}

packages/common-gax/src/index.js

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+/*!
+ * Copyright 2017 Google Inc. 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.
+ */
+
+/*!
+ * @module common-gax
+ */
+
+'use strict';
+
+/**
+ * @type {module:common-gax/service}
+ */
+exports.Service = require('./service.js');

packages/common-gax/src/service.js

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+/*!
+ * Copyright 2017 Google Inc. 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.
+ */
+
+/*!
+ * @module common-gax/service
+ */
+
+'use strict';
+
+var common = require('@google-cloud/common');
+var extend = require('extend');
+var streamEvents = require('stream-events');
+var through = require('through2');
+var util = require('util');
+
+/**
+ * GaxService is a base class, meant to be inherited from by a "service" that
+ * uses GAX.
+ *
+ * @constructor
+ * @alias module:common-gax/service
+ *
+ * @param {object} config - Configuration object.
+ * @param {*} config.module - The generated module.
+ * @param {object} options - [Configuration object](#/docs/?method=gcloud).
+ */
+function GaxService(config, options) {
+  config = extend({
+    scopes: config.module.ALL_SCOPES
+  }, config);
+
+  this.api = {};
+  this.module = config.module;
+  this.options = options;
+
+  common.Service.call(this, config, options);
+}
+
+util.inherits(GaxService, common.Service);
+
+/**
+ * Funnel all API requests through this method, to be sure we have a project ID.
+ *
+ * @param {object} config - Configuration object.
+ * @param {string} config.client - The gax client name.
+ * @param {object} config.gaxOpts - GAX options.
+ * @param {function} config.method - The gax method to call.
+ * @param {object} config.reqOpts - Request options.
+ * @param {function=} callback - The callback function.
+ */
+GaxService.prototype.request = function(config, callback) {
+  if (global.GCLOUD_SANDBOX_ENV) {
+    return;
+  }
+
+  this.prepareRequest_(config, function(err, requestFn) {
+    if (err) {
+      callback(err);
+      return;
+    }
+
+    requestFn(callback);
+  });
+};
+
+/**
+ * Make a request as a stream.
+ *
+ * @param {object} config - Configuration object.
+ * @param {string} config.client - The gax client name.
+ * @param {object} config.gaxOpts - GAX options.
+ * @param {function} config.method - The gax method to call.
+ * @param {object} config.reqOpts - Request options.
+ * @return {stream}
+ */
+GaxService.prototype.requestStream = function(config) {
+  if (global.GCLOUD_SANDBOX_ENV) {
+    return through.obj();
+  }
+
+  var self = this;
+
+  var gaxStream;
+  var stream = streamEvents(through.obj());
+
+  stream.abort = function() {
+    if (gaxStream && gaxStream.cancel) {
+      gaxStream.cancel();
+    }
+  };
+
+  stream.once('reading', function() {
+    self.prepareRequest_(config, function(err, requestFn) {
+      if (err) {
+        stream.destroy(err);
+        return;
+      }
+
+      gaxStream = requestFn();
+
+      gaxStream
+        .on('error', function(err) {
+          stream.destroy(err);
+        })
+        .pipe(stream);
+    });
+  });
+
+  return stream;
+};
+
+/**
+ * Prepare a request by instantiating and caching the GAX client. Project ID
+ * placeholder tokens will be replaced in the request options.
+ *
+ * @private
+ *
+ * @param {object} config - Configuration object.
+ * @param {string} config.client - The gax client name.
+ * @param {object} config.gaxOpts - GAX options.
+ * @param {function} config.method - The gax method to call.
+ * @param {object} config.reqOpts - Request options.
+ * @param {function=} callback - The callback function.
+ */
+GaxService.prototype.prepareRequest_ = function(config, callback) {
+  var self = this;
+
+  this.getProjectId(function(err, projectId) {
+    if (err) {
+      callback(err);
+      return;
+    }
+
+    var gaxClient = self.api[config.client];
+
+    if (!gaxClient) {
+      // Lazily instantiate client.
+      gaxClient = self.module(self.options)[config.client](self.options);
+      self.api[config.client] = gaxClient;
+    }
+
+    var reqOpts = extend(true, {}, config.reqOpts);
+    reqOpts = common.util.replaceProjectIdToken(reqOpts, projectId);
+
+    var requestFn = gaxClient[config.method].bind(
+      gaxClient,
+      reqOpts,
+      config.gaxOpts
+    );
+
+    callback(null, requestFn);
+  });
+};
+
+module.exports = GaxService;

packages/common-gax/test/index.js

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+/**
+ * Copyright 2017 Google Inc. 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';
+
+var assert = require('assert');
+var proxyquire = require('proxyquire');
+
+var fakeService = {};
+
+describe('common-gax', function() {
+  var commonGax;
+
+  before(function() {
+    commonGax = proxyquire('../src/index.js', {
+      './service.js': fakeService
+    });
+  });
+
+  it('should correctly export the commonGax modules', function() {
+    assert.deepEqual(commonGax, {
+      Service: fakeService
+    });
+  });
+});