Merge pull request #11031 from murgatroid99/node_client_refactor

Refactor client logic into superclass with generic methods, improve documentation

4 files changed, 525 insertions, 356 deletions

diff --git a/src/node/index.js b/src/node/index.js
index 071bfd7927..76ab1744b0 100644
--- a/src/node/index.js
+++ b/src/node/index.js
@@ -31,6 +31,10 @@
  *
  */
 
+/**
+ * @module
+ */
+
 'use strict';
 
 var path = require('path');
@@ -256,5 +260,10 @@ exports.getClientChannel = client.getClientChannel;
 exports.waitForClientReady = client.waitForClientReady;
 
 exports.closeClient = function closeClient(client_obj) {
-  client.getClientChannel(client_obj).close();
+  client.Client.prototype.close.apply(client_obj);
 };
+
+/**
+ * @see module:src/client.Client
+ */
+exports.Client = client.Client;
diff --git a/src/node/src/client.js b/src/node/src/client.js
index 1aaf35c16c..43502da6af 100644
--- a/src/node/src/client.js
+++ b/src/node/src/client.js
@@ -37,7 +37,7 @@
  * This module contains the factory method for creating Client classes, and the
  * method calling code for all types of methods.
  *
- * For example, to create a client and call a method on it:
+ * @example <caption>Create a client and call a method on it</caption>
  *
  * var proto_obj = grpc.load(proto_file_path);
  * var Client = proto_obj.package.subpackage.ServiceName;
@@ -68,14 +68,33 @@ var Duplex = stream.Duplex;
 var util = require('util');
 var version = require('../../../package.json').version;
 
+util.inherits(ClientUnaryCall, EventEmitter);
+
+/**
+ * An EventEmitter. Used for unary calls
+ * @constructor
+ * @extends external:EventEmitter
+ * @param {grpc.Call} call The call object associated with the request
+ */
+function ClientUnaryCall(call) {
+  EventEmitter.call(this);
+  this.call = call;
+}
+
 util.inherits(ClientWritableStream, Writable);
 
 /**
  * A stream that the client can write to. Used for calls that are streaming from
  * the client side.
  * @constructor
+ * @extends external:Writable
+ * @borrows module:src/client~ClientUnaryCall#cancel as
+ *     module:src/client~ClientWritableStream#cancel
+ * @borrows module:src/client~ClientUnaryCall#getPeer as
+ *     module:src/client~ClientWritableStream#getPeer
  * @param {grpc.Call} call The call object to send data with
- * @param {function(*):Buffer=} serialize Serialization function for writes.
+ * @param {module:src/common~serialize=} [serialize=identity] Serialization
+ *     function for writes.
  */
 function ClientWritableStream(call, serialize) {
   Writable.call(this, {objectMode: true});
@@ -134,8 +153,14 @@ util.inherits(ClientReadableStream, Readable);
  * A stream that the client can read from. Used for calls that are streaming
  * from the server side.
  * @constructor
+ * @extends external:Readable
+ * @borrows module:src/client~ClientUnaryCall#cancel as
+ *     module:src/client~ClientReadableStream#cancel
+ * @borrows module:src/client~ClientUnaryCall#getPeer as
+ *     module:src/client~ClientReadableStream#getPeer
  * @param {grpc.Call} call The call object to read data with
- * @param {function(Buffer):*=} deserialize Deserialization function for reads
+ * @param {module:src/common~deserialize=} [deserialize=identity]
+ *     Deserialization function for reads
  */
 function ClientReadableStream(call, deserialize) {
   Readable.call(this, {objectMode: true});
@@ -155,6 +180,7 @@ function ClientReadableStream(call, deserialize) {
  * parameter indicates that the call should end with that status. status
  * defaults to OK if not provided.
  * @param {Object!} status The status that the call should end with
+ * @access private
  */
 function _readsDone(status) {
   /* jshint validthis: true */
@@ -173,6 +199,7 @@ ClientReadableStream.prototype._readsDone = _readsDone;
 
 /**
  * Called to indicate that we have received a status from the server.
+ * @access private
  */
 function _receiveStatus(status) {
   /* jshint validthis: true */
@@ -185,6 +212,7 @@ ClientReadableStream.prototype._receiveStatus = _receiveStatus;
 /**
  * If we have both processed all incoming messages and received the status from
  * the server, emit the status. Otherwise, do nothing.
+ * @access private
  */
 function _emitStatusIfDone() {
   /* jshint validthis: true */
@@ -270,10 +298,16 @@ util.inherits(ClientDuplexStream, Duplex);
  * A stream that the client can read from or write to. Used for calls with
  * duplex streaming.
  * @constructor
+ * @extends external:Duplex
+ * @borrows module:src/client~ClientUnaryCall#cancel as
+ *     module:src/client~ClientDuplexStream#cancel
+ * @borrows module:src/client~ClientUnaryCall#getPeer as
+ *     module:src/client~ClientDuplexStream#getPeer
  * @param {grpc.Call} call Call object to proxy
- * @param {function(*):Buffer=} serialize Serialization function for requests
- * @param {function(Buffer):*=} deserialize Deserialization function for
- *     responses
+ * @param {module:src/common~serialize=} [serialize=identity] Serialization
+ *     function for requests
+ * @param {module:src/common~deserialize=} [deserialize=identity]
+ *     Deserialization function for responses
  */
 function ClientDuplexStream(call, serialize, deserialize) {
   Duplex.call(this, {objectMode: true});
@@ -300,12 +334,14 @@ ClientDuplexStream.prototype._write = _write;
 
 /**
  * Cancel the ongoing call
+ * @alias module:src/client~ClientUnaryCall#cancel
  */
 function cancel() {
   /* jshint validthis: true */
   this.call.cancel();
 }
 
+ClientUnaryCall.prototype.cancel = cancel;
 ClientReadableStream.prototype.cancel = cancel;
 ClientWritableStream.prototype.cancel = cancel;
 ClientDuplexStream.prototype.cancel = cancel;
@@ -313,21 +349,49 @@ ClientDuplexStream.prototype.cancel = cancel;
 /**
  * Get the endpoint this call/stream is connected to.
  * @return {string} The URI of the endpoint
+ * @alias module:src/client~ClientUnaryCall#getPeer
  */
 function getPeer() {
   /* jshint validthis: true */
   return this.call.getPeer();
 }
 
+ClientUnaryCall.prototype.getPeer = getPeer;
 ClientReadableStream.prototype.getPeer = getPeer;
 ClientWritableStream.prototype.getPeer = getPeer;
 ClientDuplexStream.prototype.getPeer = getPeer;
 
 /**
+ * Any client call type
+ * @typedef {(ClientUnaryCall|ClientReadableStream|
+ *            ClientWritableStream|ClientDuplexStream)}
+ *     module:src/client~Call
+ */
+
+/**
+ * Options that can be set on a call.
+ * @typedef {Object} module:src/client~CallOptions
+ * @property {(date|number)} deadline The deadline for the entire call to
+ *     complete. A value of Infinity indicates that no deadline should be set.
+ * @property {(string)} host Server hostname to set on the call. Only meaningful
+ *     if different from the server address used to construct the client.
+ * @property {module:src/client~Call} parent Parent call. Used in servers when
+ *     making a call as part of the process of handling a call. Used to
+ *     propagate some information automatically, as specified by
+ *     propagate_flags.
+ * @property {number} propagate_flags Indicates which properties of a parent
+ *     call should propagate to this call. Bitwise combination of flags in
+ *     [grpc.propagate]{@link module:index.propagate}.
+ * @property {module:src/credentials~CallCredentials} credentials The
+ *     credentials that should be used to make this particular call.
+ */
+
+/**
  * Get a call object built with the provided options. Keys for options are
  * 'deadline', which takes a date or number, and 'host', which takes a string
  * and overrides the hostname to connect to.
- * @param {Object} options Options map.
+ * @access private
+ * @param {module:src/client~CallOptions=} options Options object.
  */
 function getCall(channel, method, options) {
   var deadline;
@@ -354,315 +418,380 @@ function getCall(channel, method, options) {
 }
 
 /**
- * Get a function that can make unary requests to the specified method.
- * @param {string} method The name of the method to request
- * @param {function(*):Buffer} serialize The serialization function for inputs
- * @param {function(Buffer)} deserialize The deserialization function for
- *     outputs
- * @return {Function} makeUnaryRequest
+ * A generic gRPC client. Primarily useful as a base class for generated clients
+ * @alias module:src/client.Client
+ * @constructor
+ * @param {string} address Server address to connect to
+ * @param {module:src/credentials~ChannelCredentials} credentials Credentials to
+ *     use to connect to the server
+ * @param {Object} options Options to apply to channel creation
  */
-function makeUnaryRequestFunction(method, serialize, deserialize) {
-  /**
-   * Make a unary request with this method on the given channel with the given
-   * argument, callback, etc.
-   * @this {Client} Client object. Must have a channel member.
-   * @param {*} argument The argument to the call. Should be serializable with
-   *     serialize
-   * @param {Metadata=} metadata Metadata to add to the call
-   * @param {Object=} options Options map
-   * @param {function(?Error, value=)} callback The callback to for when the
-   *     response is received
-   * @return {EventEmitter} An event emitter for stream related events
+var Client = exports.Client = function Client(address, credentials, options) {
+  if (!options) {
+    options = {};
+  }
+  /* Append the grpc-node user agent string after the application user agent
+   * string, and put the combination at the beginning of the user agent string
    */
-  function makeUnaryRequest(argument, metadata, options, callback) {
-    /* jshint validthis: true */
-    /* While the arguments are listed in the function signature, those variables
-     * are not used directly. Instead, ArgueJS processes the arguments
-     * object. This allows for simple handling of optional arguments in the
-     * middle of the argument list, and also provides type checking. */
-    var args = arguejs({argument: null, metadata: [Metadata, new Metadata()],
-                        options: [Object], callback: Function}, arguments);
-    var emitter = new EventEmitter();
-    var call = getCall(this.$channel, method, args.options);
-    metadata = args.metadata.clone();
-    emitter.cancel = function cancel() {
-      call.cancel();
-    };
-    emitter.getPeer = function getPeer() {
-      return call.getPeer();
-    };
-    var client_batch = {};
-    var message = serialize(args.argument);
-    if (args.options) {
-      message.grpcWriteFlags = args.options.flags;
-    }
-
-    client_batch[grpc.opType.SEND_INITIAL_METADATA] =
-        metadata._getCoreRepresentation();
-    client_batch[grpc.opType.SEND_MESSAGE] = message;
-    client_batch[grpc.opType.SEND_CLOSE_FROM_CLIENT] = true;
-    client_batch[grpc.opType.RECV_INITIAL_METADATA] = true;
-    client_batch[grpc.opType.RECV_MESSAGE] = true;
-    client_batch[grpc.opType.RECV_STATUS_ON_CLIENT] = true;
-    call.startBatch(client_batch, function(err, response) {
-      response.status.metadata = Metadata._fromCoreRepresentation(
-          response.status.metadata);
-      var status = response.status;
-      var error;
-      var deserialized;
-      emitter.emit('metadata', Metadata._fromCoreRepresentation(
-          response.metadata));
-      if (status.code === grpc.status.OK) {
-        if (err) {
-          // Got a batch error, but OK status. Something went wrong
-          args.callback(err);
-          return;
-        } else {
-          try {
-            deserialized = deserialize(response.read);
-          } catch (e) {
-            /* Change status to indicate bad server response. This will result
-             * in passing an error to the callback */
-            status = {
-              code: grpc.status.INTERNAL,
-              details: 'Failed to parse server response'
-            };
-          }
-        }
-      }
-      if (status.code !== grpc.status.OK) {
-        error = new Error(status.details);
-        error.code = status.code;
-        error.metadata = status.metadata;
-        args.callback(error);
-      } else {
-        args.callback(null, deserialized);
-      }
-      emitter.emit('status', status);
-    });
-    return emitter;
+  if (options['grpc.primary_user_agent']) {
+    options['grpc.primary_user_agent'] += ' ';
+  } else {
+    options['grpc.primary_user_agent'] = '';
   }
-  return makeUnaryRequest;
-}
+  options['grpc.primary_user_agent'] += 'grpc-node/' + version;
+  /* Private fields use $ as a prefix instead of _ because it is an invalid
+   * prefix of a method name */
+  this.$channel = new grpc.Channel(address, credentials, options);
+};
 
 /**
- * Get a function that can make client stream requests to the specified method.
+ * @typedef {Error} module:src/client.Client~ServiceError
+ * @property {number} code The error code, a key of
+ *     [grpc.status]{@link module:src/client.status}
+ * @property {module:metadata.Metadata} metadata Metadata sent with the status
+ *     by the server, if any
+ */
+
+/**
+ * @callback module:src/client.Client~requestCallback
+ * @param {?module:src/client.Client~ServiceError} error The error, if the call
+ *     failed
+ * @param {*} value The response value, if the call succeeded
+ */
+
+/**
+ * Make a unary request to the given method, using the given serialize
+ * and deserialize functions, with the given argument.
  * @param {string} method The name of the method to request
- * @param {function(*):Buffer} serialize The serialization function for inputs
- * @param {function(Buffer)} deserialize The deserialization function for
- *     outputs
- * @return {Function} makeClientStreamRequest
+ * @param {module:src/common~serialize} serialize The serialization function for
+ *     inputs
+ * @param {module:src/common~deserialize} deserialize The deserialization
+ *     function for outputs
+ * @param {*} argument The argument to the call. Should be serializable with
+ *     serialize
+ * @param {module:src/metadata.Metadata=} metadata Metadata to add to the call
+ * @param {module:src/client~CallOptions=} options Options map
+ * @param {module:src/client.Client~requestCallback} callback The callback to
+ *     for when the response is received
+ * @return {EventEmitter} An event emitter for stream related events
  */
-function makeClientStreamRequestFunction(method, serialize, deserialize) {
-  /**
-   * Make a client stream request with this method on the given channel with the
-   * given callback, etc.
-   * @this {Client} Client object. Must have a channel member.
-   * @param {Metadata=} metadata Array of metadata key/value pairs to add to the
-   *     call
-   * @param {Object=} options Options map
-   * @param {function(?Error, value=)} callback The callback to for when the
-   *     response is received
-   * @return {EventEmitter} An event emitter for stream related events
-   */
-  function makeClientStreamRequest(metadata, options, callback) {
-    /* jshint validthis: true */
-    /* While the arguments are listed in the function signature, those variables
-     * are not used directly. Instead, ArgueJS processes the arguments
-     * object. This allows for simple handling of optional arguments in the
-     * middle of the argument list, and also provides type checking. */
-    var args = arguejs({metadata: [Metadata, new Metadata()],
-                        options: [Object], callback: Function}, arguments);
-    var call = getCall(this.$channel, method, args.options);
-    metadata = args.metadata.clone();
-    var stream = new ClientWritableStream(call, serialize);
-    var metadata_batch = {};
-    metadata_batch[grpc.opType.SEND_INITIAL_METADATA] =
-        metadata._getCoreRepresentation();
-    metadata_batch[grpc.opType.RECV_INITIAL_METADATA] = true;
-    call.startBatch(metadata_batch, function(err, response) {
+Client.prototype.makeUnaryRequest = function(method, serialize, deserialize,
+                                             argument, metadata, options,
+                                             callback) {
+  /* While the arguments are listed in the function signature, those variables
+   * are not used directly. Instead, ArgueJS processes the arguments
+   * object. This allows for simple handling of optional arguments in the
+   * middle of the argument list, and also provides type checking. */
+  var args = arguejs({method: String, serialize: Function,
+                      deserialize: Function,
+                      argument: null, metadata: [Metadata, new Metadata()],
+                      options: [Object], callback: Function}, arguments);
+  var call = getCall(this.$channel, method, args.options);
+  var emitter = new ClientUnaryCall(call);
+  metadata = args.metadata.clone();
+  var client_batch = {};
+  var message = serialize(args.argument);
+  if (args.options) {
+    message.grpcWriteFlags = args.options.flags;
+  }
+
+  client_batch[grpc.opType.SEND_INITIAL_METADATA] =
+      metadata._getCoreRepresentation();
+  client_batch[grpc.opType.SEND_MESSAGE] = message;
+  client_batch[grpc.opType.SEND_CLOSE_FROM_CLIENT] = true;
+  client_batch[grpc.opType.RECV_INITIAL_METADATA] = true;
+  client_batch[grpc.opType.RECV_MESSAGE] = true;
+  client_batch[grpc.opType.RECV_STATUS_ON_CLIENT] = true;
+  call.startBatch(client_batch, function(err, response) {
+    response.status.metadata = Metadata._fromCoreRepresentation(
+        response.status.metadata);
+    var status = response.status;
+    var error;
+    var deserialized;
+    emitter.emit('metadata', Metadata._fromCoreRepresentation(
+        response.metadata));
+    if (status.code === grpc.status.OK) {
       if (err) {
-        // The call has stopped for some reason. A non-OK status will arrive
-        // in the other batch.
+        // Got a batch error, but OK status. Something went wrong
+        args.callback(err);
         return;
-      }
-      stream.emit('metadata', Metadata._fromCoreRepresentation(
-          response.metadata));
-    });
-    var client_batch = {};
-    client_batch[grpc.opType.RECV_MESSAGE] = true;
-    client_batch[grpc.opType.RECV_STATUS_ON_CLIENT] = true;
-    call.startBatch(client_batch, function(err, response) {
-      response.status.metadata = Metadata._fromCoreRepresentation(
-          response.status.metadata);
-      var status = response.status;
-      var error;
-      var deserialized;
-      if (status.code === grpc.status.OK) {
-        if (err) {
-          // Got a batch error, but OK status. Something went wrong
-          args.callback(err);
-          return;
-        } else {
-          try {
-            deserialized = deserialize(response.read);
-          } catch (e) {
-            /* Change status to indicate bad server response. This will result
-             * in passing an error to the callback */
-            status = {
-              code: grpc.status.INTERNAL,
-              details: 'Failed to parse server response'
-            };
-          }
-        }
-      }
-      if (status.code !== grpc.status.OK) {
-        error = new Error(response.status.details);
-        error.code = status.code;
-        error.metadata = status.metadata;
-        args.callback(error);
       } else {
-        args.callback(null, deserialized);
+        try {
+          deserialized = deserialize(response.read);
+        } catch (e) {
+          /* Change status to indicate bad server response. This will result
+           * in passing an error to the callback */
+          status = {
+            code: grpc.status.INTERNAL,
+            details: 'Failed to parse server response'
+          };
+        }
       }
-      stream.emit('status', status);
-    });
-    return stream;
-  }
-  return makeClientStreamRequest;
-}
+    }
+    if (status.code !== grpc.status.OK) {
+      error = new Error(status.details);
+      error.code = status.code;
+      error.metadata = status.metadata;
+      args.callback(error);
+    } else {
+      args.callback(null, deserialized);
+    }
+    emitter.emit('status', status);
+  });
+  return emitter;
+};
 
 /**
- * Get a function that can make server stream requests to the specified method.
+ * Make a client stream request to the given method, using the given serialize
+ * and deserialize functions, with the given argument.
  * @param {string} method The name of the method to request
- * @param {function(*):Buffer} serialize The serialization function for inputs
- * @param {function(Buffer)} deserialize The deserialization function for
- *     outputs
- * @return {Function} makeServerStreamRequest
+ * @param {module:src/common~serialize} serialize The serialization function for
+ *     inputs
+ * @param {module:src/common~deserialize} deserialize The deserialization
+ *     function for outputs
+ * @param {module:src/metadata.Metadata=} metadata Array of metadata key/value
+ *     pairs to add to the call
+ * @param {module:src/client~CallOptions=} options Options map
+ * @param {Client~requestCallback} callback The callback to for when the
+ *     response is received
+ * @return {module:src/client~ClientWritableStream} An event emitter for stream
+ *     related events
  */
-function makeServerStreamRequestFunction(method, serialize, deserialize) {
-  /**
-   * Make a server stream request with this method on the given channel with the
-   * given argument, etc.
-   * @this {SurfaceClient} Client object. Must have a channel member.
-   * @param {*} argument The argument to the call. Should be serializable with
-   *     serialize
-   * @param {Metadata=} metadata Array of metadata key/value pairs to add to the
-   *     call
-   * @param {Object} options Options map
-   * @return {EventEmitter} An event emitter for stream related events
-   */
-  function makeServerStreamRequest(argument, metadata, options) {
-    /* jshint validthis: true */
-    /* While the arguments are listed in the function signature, those variables
-     * are not used directly. Instead, ArgueJS processes the arguments
-     * object. */
-    var args = arguejs({argument: null, metadata: [Metadata, new Metadata()],
-                        options: [Object]}, arguments);
-    var call = getCall(this.$channel, method, args.options);
-    metadata = args.metadata.clone();
-    var stream = new ClientReadableStream(call, deserialize);
-    var start_batch = {};
-    var message = serialize(args.argument);
-    if (args.options) {
-      message.grpcWriteFlags = args.options.flags;
+Client.prototype.makeClientStreamRequest = function(method, serialize,
+                                                      deserialize, metadata,
+                                                      options, callback) {
+  /* While the arguments are listed in the function signature, those variables
+   * are not used directly. Instead, ArgueJS processes the arguments
+   * object. This allows for simple handling of optional arguments in the
+   * middle of the argument list, and also provides type checking. */
+  var args = arguejs({method:String, serialize: Function,
+                      deserialize: Function,
+                      metadata: [Metadata, new Metadata()],
+                      options: [Object], callback: Function}, arguments);
+  var call = getCall(this.$channel, method, args.options);
+  metadata = args.metadata.clone();
+  var stream = new ClientWritableStream(call, serialize);
+  var metadata_batch = {};
+  metadata_batch[grpc.opType.SEND_INITIAL_METADATA] =
+      metadata._getCoreRepresentation();
+  metadata_batch[grpc.opType.RECV_INITIAL_METADATA] = true;
+  call.startBatch(metadata_batch, function(err, response) {
+    if (err) {
+      // The call has stopped for some reason. A non-OK status will arrive
+      // in the other batch.
+      return;
     }
-    start_batch[grpc.opType.SEND_INITIAL_METADATA] =
-        metadata._getCoreRepresentation();
-    start_batch[grpc.opType.RECV_INITIAL_METADATA] = true;
-    start_batch[grpc.opType.SEND_MESSAGE] = message;
-    start_batch[grpc.opType.SEND_CLOSE_FROM_CLIENT] = true;
-    call.startBatch(start_batch, function(err, response) {
-      if (err) {
-        // The call has stopped for some reason. A non-OK status will arrive
-        // in the other batch.
-        return;
-      }
-      stream.emit('metadata', Metadata._fromCoreRepresentation(
-          response.metadata));
-    });
-    var status_batch = {};
-    status_batch[grpc.opType.RECV_STATUS_ON_CLIENT] = true;
-    call.startBatch(status_batch, function(err, response) {
+    stream.emit('metadata', Metadata._fromCoreRepresentation(
+        response.metadata));
+  });
+  var client_batch = {};
+  client_batch[grpc.opType.RECV_MESSAGE] = true;
+  client_batch[grpc.opType.RECV_STATUS_ON_CLIENT] = true;
+  call.startBatch(client_batch, function(err, response) {
+    response.status.metadata = Metadata._fromCoreRepresentation(
+        response.status.metadata);
+    var status = response.status;
+    var error;
+    var deserialized;
+    if (status.code === grpc.status.OK) {
       if (err) {
-        stream.emit('error', err);
+        // Got a batch error, but OK status. Something went wrong
+        args.callback(err);
         return;
+      } else {
+        try {
+          deserialized = deserialize(response.read);
+        } catch (e) {
+          /* Change status to indicate bad server response. This will result
+           * in passing an error to the callback */
+          status = {
+            code: grpc.status.INTERNAL,
+            details: 'Failed to parse server response'
+          };
+        }
       }
-      response.status.metadata = Metadata._fromCoreRepresentation(
-          response.status.metadata);
-      stream._receiveStatus(response.status);
-    });
-    return stream;
-  }
-  return makeServerStreamRequest;
-}
+    }
+    if (status.code !== grpc.status.OK) {
+      error = new Error(response.status.details);
+      error.code = status.code;
+      error.metadata = status.metadata;
+      args.callback(error);
+    } else {
+      args.callback(null, deserialized);
+    }
+    stream.emit('status', status);
+  });
+  return stream;
+};
 
 /**
- * Get a function that can make bidirectional stream requests to the specified
- * method.
+ * Make a server stream request to the given method, with the given serialize
+ * and deserialize function, using the given argument
  * @param {string} method The name of the method to request
- * @param {function(*):Buffer} serialize The serialization function for inputs
- * @param {function(Buffer)} deserialize The deserialization function for
- *     outputs
- * @return {Function} makeBidiStreamRequest
+ * @param {module:src/common~serialize} serialize The serialization function for
+ *     inputs
+ * @param {module:src/common~deserialize} deserialize The deserialization
+ *     function for outputs
+ * @param {*} argument The argument to the call. Should be serializable with
+ *     serialize
+ * @param {module:src/metadata.Metadata=} metadata Array of metadata key/value
+ *     pairs to add to the call
+ * @param {module:src/client~CallOptions=} options Options map
+ * @return {module:src/client~ClientReadableStream} An event emitter for stream
+ *     related events
  */
-function makeBidiStreamRequestFunction(method, serialize, deserialize) {
-  /**
-   * Make a bidirectional stream request with this method on the given channel.
-   * @this {SurfaceClient} Client object. Must have a channel member.
-   * @param {Metadata=} metadata Array of metadata key/value pairs to add to the
-   *     call
-   * @param {Options} options Options map
-   * @return {EventEmitter} An event emitter for stream related events
-   */
-  function makeBidiStreamRequest(metadata, options) {
-    /* jshint validthis: true */
-    /* While the arguments are listed in the function signature, those variables
-     * are not used directly. Instead, ArgueJS processes the arguments
-     * object. */
-    var args = arguejs({metadata: [Metadata, new Metadata()],
-                        options: [Object]}, arguments);
-    var call = getCall(this.$channel, method, args.options);
-    metadata = args.metadata.clone();
-    var stream = new ClientDuplexStream(call, serialize, deserialize);
-    var start_batch = {};
-    start_batch[grpc.opType.SEND_INITIAL_METADATA] =
-        metadata._getCoreRepresentation();
-    start_batch[grpc.opType.RECV_INITIAL_METADATA] = true;
-    call.startBatch(start_batch, function(err, response) {
-      if (err) {
-        // The call has stopped for some reason. A non-OK status will arrive
-        // in the other batch.
-        return;
-      }
-      stream.emit('metadata', Metadata._fromCoreRepresentation(
-          response.metadata));
-    });
-    var status_batch = {};
-    status_batch[grpc.opType.RECV_STATUS_ON_CLIENT] = true;
-    call.startBatch(status_batch, function(err, response) {
-      if (err) {
-        stream.emit('error', err);
-        return;
-      }
-      response.status.metadata = Metadata._fromCoreRepresentation(
-          response.status.metadata);
-      stream._receiveStatus(response.status);
-    });
-    return stream;
+Client.prototype.makeServerStreamRequest = function(method, serialize,
+                                                    deserialize, argument,
+                                                    metadata, options) {
+  /* While the arguments are listed in the function signature, those variables
+   * are not used directly. Instead, ArgueJS processes the arguments
+   * object. */
+  var args = arguejs({method:String, serialize: Function,
+                      deserialize: Function,
+                      argument: null, metadata: [Metadata, new Metadata()],
+                      options: [Object]}, arguments);
+  var call = getCall(this.$channel, method, args.options);
+  metadata = args.metadata.clone();
+  var stream = new ClientReadableStream(call, deserialize);
+  var start_batch = {};
+  var message = serialize(args.argument);
+  if (args.options) {
+    message.grpcWriteFlags = args.options.flags;
   }
-  return makeBidiStreamRequest;
-}
+  start_batch[grpc.opType.SEND_INITIAL_METADATA] =
+      metadata._getCoreRepresentation();
+  start_batch[grpc.opType.RECV_INITIAL_METADATA] = true;
+  start_batch[grpc.opType.SEND_MESSAGE] = message;
+  start_batch[grpc.opType.SEND_CLOSE_FROM_CLIENT] = true;
+  call.startBatch(start_batch, function(err, response) {
+    if (err) {
+      // The call has stopped for some reason. A non-OK status will arrive
+      // in the other batch.
+      return;
+    }
+    stream.emit('metadata', Metadata._fromCoreRepresentation(
+        response.metadata));
+  });
+  var status_batch = {};
+  status_batch[grpc.opType.RECV_STATUS_ON_CLIENT] = true;
+  call.startBatch(status_batch, function(err, response) {
+    if (err) {
+      stream.emit('error', err);
+      return;
+    }
+    response.status.metadata = Metadata._fromCoreRepresentation(
+        response.status.metadata);
+    stream._receiveStatus(response.status);
+  });
+  return stream;
+};
+
+
+/**
+ * Make a bidirectional stream request with this method on the given channel.
+ * @param {string} method The name of the method to request
+ * @param {module:src/common~serialize} serialize The serialization function for
+ *     inputs
+ * @param {module:src/common~deserialize} deserialize The deserialization
+ *     function for outputs
+ * @param {module:src/metadata.Metadata=} metadata Array of metadata key/value
+ *     pairs to add to the call
+ * @param {module:src/client~CallOptions=} options Options map
+ * @return {module:src/client~ClientDuplexStream} An event emitter for stream
+ *     related events
+ */
+Client.prototype.makeBidiStreamRequest = function(method, serialize,
+                                                  deserialize, metadata,
+                                                  options) {
+  /* While the arguments are listed in the function signature, those variables
+   * are not used directly. Instead, ArgueJS processes the arguments
+   * object. */
+  var args = arguejs({method:String, serialize: Function,
+                      deserialize: Function,
+                      metadata: [Metadata, new Metadata()],
+                      options: [Object]}, arguments);
+  var call = getCall(this.$channel, method, args.options);
+  metadata = args.metadata.clone();
+  var stream = new ClientDuplexStream(call, serialize, deserialize);
+  var start_batch = {};
+  start_batch[grpc.opType.SEND_INITIAL_METADATA] =
+      metadata._getCoreRepresentation();
+  start_batch[grpc.opType.RECV_INITIAL_METADATA] = true;
+  call.startBatch(start_batch, function(err, response) {
+    if (err) {
+      // The call has stopped for some reason. A non-OK status will arrive
+      // in the other batch.
+      return;
+    }
+    stream.emit('metadata', Metadata._fromCoreRepresentation(
+        response.metadata));
+  });
+  var status_batch = {};
+  status_batch[grpc.opType.RECV_STATUS_ON_CLIENT] = true;
+  call.startBatch(status_batch, function(err, response) {
+    if (err) {
+      stream.emit('error', err);
+      return;
+    }
+    response.status.metadata = Metadata._fromCoreRepresentation(
+        response.status.metadata);
+    stream._receiveStatus(response.status);
+  });
+  return stream;
+};
 
+Client.prototype.close = function() {
+  this.$channel.close();
+};
+
+/**
+ * Return the underlying channel object for the specified client
+ * @return {Channel} The channel
+ */
+Client.prototype.getChannel = function() {
+  return this.$channel;
+};
+
+/**
+ * Wait for the client to be ready. The callback will be called when the
+ * client has successfully connected to the server, and it will be called
+ * with an error if the attempt to connect to the server has unrecoverablly
+ * failed or if the deadline expires. This function will make the channel
+ * start connecting if it has not already done so.
+ * @param {(Date|Number)} deadline When to stop waiting for a connection. Pass
+ *     Infinity to wait forever.
+ * @param {function(Error)} callback The callback to call when done attempting
+ *     to connect.
+ */
+Client.prototype.waitForReady = function(deadline, callback) {
+  var self = this;
+  var checkState = function(err) {
+    if (err) {
+      callback(new Error('Failed to connect before the deadline'));
+      return;
+    }
+    var new_state = self.$channel.getConnectivityState(true);
+    if (new_state === grpc.connectivityState.READY) {
+      callback();
+    } else if (new_state === grpc.connectivityState.FATAL_FAILURE) {
+      callback(new Error('Failed to connect to server'));
+    } else {
+      self.$channel.watchConnectivityState(new_state, deadline, checkState);
+    }
+  };
+  checkState();
+};
 
 /**
  * Map with short names for each of the requester maker functions. Used in
  * makeClientConstructor
+ * @access private
  */
-var requester_makers = {
-  unary: makeUnaryRequestFunction,
-  server_stream: makeServerStreamRequestFunction,
-  client_stream: makeClientStreamRequestFunction,
-  bidi: makeBidiStreamRequestFunction
+var requester_funcs = {
+  unary: Client.prototype.makeUnaryRequest,
+  server_stream: Client.prototype.makeServerStreamRequest,
+  client_stream: Client.prototype.makeClientStreamRequest,
+  bidi: Client.prototype.makeBidiStreamRequest
 };
 
 function getDefaultValues(metadata, options) {
@@ -675,6 +804,7 @@ function getDefaultValues(metadata, options) {
 /**
  * Map with wrappers for each type of requester function to make it use the old
  * argument order with optional arguments after the callback.
+ * @access private
  */
 var deprecated_request_wrap = {
   unary: function(makeUnaryRequest) {
@@ -700,55 +830,33 @@ var deprecated_request_wrap = {
 };
 
 /**
- * Creates a constructor for a client with the given methods. The methods object
- * maps method name to an object with the following keys:
- * path: The path on the server for accessing the method. For example, for
- *     protocol buffers, we use "/service_name/method_name"
- * requestStream: bool indicating whether the client sends a stream
- * resonseStream: bool indicating whether the server sends a stream
- * requestSerialize: function to serialize request objects
- * responseDeserialize: function to deserialize response objects
- * @param {Object} methods An object mapping method names to method attributes
+ * Creates a constructor for a client with the given methods, as specified in
+ * the methods argument.
+ * @param {module:src/common~ServiceDefinition} methods An object mapping
+ *     method names to method attributes
  * @param {string} serviceName The fully qualified name of the service
- * @param {Object} class_options An options object. Currently only uses the key
- *     deprecatedArgumentOrder, a boolean that Indicates that the old argument
- *     order should be used for methods, with optional arguments at the end
- *     instead of the callback at the end. Defaults to false. This option is
- *     only a temporary stopgap measure to smooth an API breakage.
+ * @param {Object} class_options An options object.
+ * @param {boolean=} [class_options.deprecatedArgumentOrder=false] Indicates
+ *     that the old argument order should be used for methods, with optional
+ *     arguments at the end instead of the callback at the end. This option
+ *     is only a temporary stopgap measure to smooth an API breakage.
  *     It is deprecated, and new code should not use it.
- * @return {function(string, Object)} New client constructor
+ * @return {function(string, Object)} New client constructor, which is a
+ *     subclass of [grpc.Client]{@link module:src/client.Client}, and has the
+ *     same arguments as that constructor.
  */
 exports.makeClientConstructor = function(methods, serviceName,
                                          class_options) {
   if (!class_options) {
     class_options = {};
   }
-  /**
-   * Create a client with the given methods
-   * @constructor
-   * @param {string} address The address of the server to connect to
-   * @param {grpc.Credentials} credentials Credentials to use to connect
-   *     to the server
-   * @param {Object} options Options to pass to the underlying channel
-   */
-  function Client(address, credentials, options) {
-    if (!options) {
-      options = {};
-    }
-    /* Append the grpc-node user agent string after the application user agent
-     * string, and put the combination at the beginning of the user agent string
-     */
-    if (options['grpc.primary_user_agent']) {
-      options['grpc.primary_user_agent'] += ' ';
-    } else {
-      options['grpc.primary_user_agent'] = '';
-    }
-    options['grpc.primary_user_agent'] += 'grpc-node/' + version;
-    /* Private fields use $ as a prefix instead of _ because it is an invalid
-     * prefix of a method name */
-    this.$channel = new grpc.Channel(address, credentials, options);
+
+  function ServiceClient(address, credentials, options) {
+    Client.call(this, address, credentials, options);
   }
 
+  util.inherits(ServiceClient, Client);
+
   _.each(methods, function(attrs, name) {
     var method_type;
     if (_.startsWith(name, '$')) {
@@ -769,20 +877,20 @@ exports.makeClientConstructor = function(methods, serviceName,
     }
     var serialize = attrs.requestSerialize;
     var deserialize = attrs.responseDeserialize;
-    var method_func = requester_makers[method_type](
-        attrs.path, serialize, deserialize);
+    var method_func = _.partial(requester_funcs[method_type], attrs.path,
+                                serialize, deserialize);
     if (class_options.deprecatedArgumentOrder) {
-      Client.prototype[name] = deprecated_request_wrap(method_func);
+      ServiceClient.prototype[name] = deprecated_request_wrap(method_func);
     } else {
-      Client.prototype[name] = method_func;
+      ServiceClient.prototype[name] = method_func;
     }
     // Associate all provided attributes with the method
-    _.assign(Client.prototype[name], attrs);
+    _.assign(ServiceClient.prototype[name], attrs);
   });
 
-  Client.service = methods;
+  ServiceClient.service = methods;
 
-  return Client;
+  return ServiceClient;
 };
 
 /**
@@ -791,7 +899,7 @@ exports.makeClientConstructor = function(methods, serviceName,
  * @return {Channel} The channel
  */
 exports.getClientChannel = function(client) {
-  return client.$channel;
+  return Client.prototype.getChannel.call(client);
 };
 
 /**
@@ -807,21 +915,7 @@ exports.getClientChannel = function(client) {
  *     to connect.
  */
 exports.waitForClientReady = function(client, deadline, callback) {
-  var checkState = function(err) {
-    if (err) {
-      callback(new Error('Failed to connect before the deadline'));
-      return;
-    }
-    var new_state = client.$channel.getConnectivityState(true);
-    if (new_state === grpc.connectivityState.READY) {
-      callback();
-    } else if (new_state === grpc.connectivityState.FATAL_FAILURE) {
-      callback(new Error('Failed to connect to server'));
-    } else {
-      client.$channel.watchConnectivityState(new_state, deadline, checkState);
-    }
-  };
-  checkState();
+  Client.prototype.waitForReady.call(client, deadline, callback);
 };
 
 /**
diff --git a/src/node/src/common.js b/src/node/src/common.js
index 757969dbdd..4dad60e630 100644
--- a/src/node/src/common.js
+++ b/src/node/src/common.js
@@ -43,7 +43,8 @@ var _ = require('lodash');
 
 /**
  * Wrap a function to pass null-like values through without calling it. If no
- * function is given, just uses the identity;
+ * function is given, just uses the identity.
+ * @private
  * @param {?function} func The function to wrap
  * @return {function} The wrapped function
  */
@@ -90,3 +91,67 @@ exports.defaultGrpcOptions = {
   enumsAsStrings: true,
   deprecatedArgumentOrder: false
 };
+
+// JSDoc definitions that are used in multiple other modules
+
+/**
+ * The EventEmitter class in the event standard module
+ * @external EventEmitter
+ * @see https://nodejs.org/api/events.html#events_class_eventemitter
+ */
+
+/**
+ * The Readable class in the stream standard module
+ * @external Readable
+ * @see https://nodejs.org/api/stream.html#stream_readable_streams
+ */
+
+/**
+ * The Writable class in the stream standard module
+ * @external Writable
+ * @see https://nodejs.org/api/stream.html#stream_writable_streams
+ */
+
+/**
+ * The Duplex class in the stream standard module
+ * @external Duplex
+ * @see https://nodejs.org/api/stream.html#stream_class_stream_duplex
+ */
+
+/**
+ * A serialization function
+ * @callback module:src/common~serialize
+ * @param {*} value The value to serialize
+ * @return {Buffer} The value serialized as a byte sequence
+ */
+
+/**
+ * A deserialization function
+ * @callback module:src/common~deserialize
+ * @param {Buffer} data The byte sequence to deserialize
+ * @return {*} The data deserialized as a value
+ */
+
+/**
+ * An object that completely defines a service method signature.
+ * @typedef {Object} module:src/common~MethodDefinition
+ * @property {string} path The method's URL path
+ * @property {boolean} requestStream Indicates whether the method accepts
+ *     a stream of requests
+ * @property {boolean} responseStream Indicates whether the method returns
+ *     a stream of responses
+ * @property {module:src/common~serialize} requestSerialize Serialization
+ *     function for request values
+ * @property {module:src/common~serialize} responseSerialize Serialization
+ *     function for response values
+ * @property {module:src/common~deserialize} requestDeserialize Deserialization
+ *     function for request data
+ * @property {module:src/common~deserialize} responseDeserialize Deserialization
+ *     function for repsonse data
+ */
+
+/**
+ * An object that completely defines a service.
+ * @typedef {Object.<string, module:src/common~MethodDefinition>}
+ *     module:src/common~ServiceDefinition
+ */
diff --git a/src/node/src/metadata.js b/src/node/src/metadata.js
index 612361b0ea..92cf23998b 100644
--- a/src/node/src/metadata.js
+++ b/src/node/src/metadata.js
@@ -35,12 +35,7 @@
  * Metadata module
  *
  * This module defines the Metadata class, which represents header and trailer
- * metadata for gRPC calls. Here is an example of how to use it:
- *
- * var metadata = new metadata_module.Metadata();
- * metadata.set('key1', 'value1');
- * metadata.add('key1', 'value2');
- * metadata.get('key1') // returns ['value1', 'value2']
+ * metadata for gRPC calls.
  *
  * @module
  */
@@ -54,6 +49,12 @@ var grpc = require('./grpc_extension');
 /**
  * Class for storing metadata. Keys are normalized to lowercase ASCII.
  * @constructor
+ * @alias module:src/metadata.Metadata
+ * @example
+ * var metadata = new metadata_module.Metadata();
+ * metadata.set('key1', 'value1');
+ * metadata.add('key1', 'value2');
+ * metadata.get('key1') // returns ['value1', 'value2']
  */
 function Metadata() {
   this._internal_repr = {};