feat(cryptdConnectionString): makes mongocryptd uri configurable (#2049)

* perf(cryptdConnectionString): make mongocryptd uri configurable by creating the property `autoEncryption.extraOptions.mongocryptURI`

Fixes NODE-2012

Author: rosemaryy

lib/mongo_client.js

@@ -67,6 +67,7 @@ const closeOperation = require('./operations/mongo_client_ops').closeOperation;
  * @property {string} [kmsProviders.local.key] The master key used to encrypt/decrypt data keys
  * @property {object} [schemaMap] A map of namespaces to a local JSON schema for encryption
  * @property {boolean} [bypassAutoEncryption] Allows the user to bypass auto encryption, maintaining implicit decryption
+ * @param {string} [extraOptions.mongocryptURI] A local process the driver communicates with to determine how to encrypt values in a command. Defaults to "mongodb://%2Fvar%2Fmongocryptd.sock" if domain sockets are available or "mongodb://localhost:27020" otherwise.
  */
 
 /**

lib/operations/mongo_client_ops.js

@@ -439,10 +439,14 @@ function createTopology(mongoClient, topologyType, options, callback) {
     }
 
     const MongoClient = loadClient();
-    const connectionString =
-      os.platform() === 'win32'
-        ? 'mongodb://localhost:27020/?serverSelectionTimeoutMS=1000'
-        : 'mongodb://%2Ftmp%2Fmongocryptd.sock/?serverSelectionTimeoutMS=1000';
+    let connectionString;
+    if (options.autoEncryption.extraOptions && options.autoEncryption.extraOptions.mongocryptURI) {
+      connectionString = options.autoEncryption.extraOptions.mongocryptURI;
+    } else if (os.platform() === 'win32') {
+      connectionString = 'mongodb://localhost:27020/?serverSelectionTimeoutMS=1000';
+    } else {
+      connectionString = 'mongodb://%2Ftmp%2Fmongocryptd.sock/?serverSelectionTimeoutMS=1000';
+    }
 
     const mongocryptdClient = new MongoClient(connectionString, { useUnifiedTopology: true });
     mongocryptdClient.connect(err => {