Initial checkin of gRPC to third_party/

third_party/grpc/src/ruby/lib/grpc/generic/client_stub.rb

Index: third_party/grpc/src/ruby/lib/grpc/generic/client_stub.rb
diff --git a/third_party/grpc/src/ruby/lib/grpc/generic/client_stub.rb b/third_party/grpc/src/ruby/lib/grpc/generic/client_stub.rb
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+# Copyright 2015-2016, 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.
+
+require 'grpc/generic/active_call'
+require 'grpc/version'
+
+# GRPC contains the General RPC module.
+module GRPC
+  # rubocop:disable Metrics/ParameterLists
+
+  # ClientStub represents an endpoint used to send requests to GRPC servers.
+  class ClientStub
+    include Core::StatusCodes
+    include Core::TimeConsts
+
+    # Default timeout is infinity.
+    DEFAULT_TIMEOUT = INFINITE_FUTURE
+
+    # setup_channel is used by #initialize to constuct a channel from its
+    # arguments.
+    def self.setup_channel(alt_chan, host, creds, **kw)
+      unless alt_chan.nil?
+        fail(TypeError, '!Channel') unless alt_chan.is_a?(Core::Channel)
+        return alt_chan
+      end
+      kw['grpc.primary_user_agent'] = "grpc-ruby/#{VERSION}"
+      unless creds.is_a?(Core::ChannelCredentials) || creds.is_a?(Symbol)
+        fail(TypeError, '!ChannelCredentials or Symbol')
+      end
+      Core::Channel.new(host, kw, creds)
+    end
+
+    # Allows users of the stub to modify the propagate mask.
+    #
+    # This is an advanced feature for use when making calls to another gRPC
+    # server whilst running in the handler of an existing one.
+    attr_writer :propagate_mask
+
+    # Creates a new ClientStub.
+    #
+    # Minimally, a stub is created with the just the host of the gRPC service
+    # it wishes to access, e.g.,
+    #
+    # my_stub = ClientStub.new(example.host.com:50505,
+    #                          :this_channel_is_insecure)
+    #
+    # Any arbitrary keyword arguments are treated as channel arguments used to
+    # configure the RPC connection to the host.
+    #
+    # There are some specific keyword args that are not used to configure the
+    # channel:
+    #
+    # - :channel_override
+    # when present, this must be a pre-created GRPC::Channel.  If it's
+    # present the host and arbitrary keyword arg areignored, and the RPC
+    # connection uses this channel.
+    #
+    # - :timeout
+    # when present, this is the default timeout used for calls
+    #
+    # @param host [String] the host the stub connects to
+    # @param q [Core::CompletionQueue] used to wait for events
+    # @param creds [Core::ChannelCredentials|Symbol] the channel credentials, or
+    #     :this_channel_is_insecure
+    # @param channel_override [Core::Channel] a pre-created channel
+    # @param timeout [Number] the default timeout to use in requests
+    # @param kw [KeywordArgs]the channel arguments
+    def initialize(host, q, creds,
+                   channel_override: nil,
+                   timeout: nil,
+                   propagate_mask: nil,
+                   **kw)
+      fail(TypeError, '!CompletionQueue') unless q.is_a?(Core::CompletionQueue)
+      @queue = q
+      @ch = ClientStub.setup_channel(channel_override, host, creds, **kw)
+      alt_host = kw[Core::Channel::SSL_TARGET]
+      @host = alt_host.nil? ? host : alt_host
+      @propagate_mask = propagate_mask
+      @timeout = timeout.nil? ? DEFAULT_TIMEOUT : timeout
+    end
+
+    # request_response sends a request to a GRPC server, and returns the
+    # response.
+    #
+    # == Flow Control ==
+    # This is a blocking call.
+    #
+    # * it does not return until a response is received.
+    #
+    # * the requests is sent only when GRPC core's flow control allows it to
+    #   be sent.
+    #
+    # == Errors ==
+    # An RuntimeError is raised if
+    #
+    # * the server responds with a non-OK status
+    #
+    # * the deadline is exceeded
+    #
+    # == Return Value ==
+    #
+    # If return_op is false, the call returns the response
+    #
+    # If return_op is true, the call returns an Operation, calling execute
+    # on the Operation returns the response.
+    #
+    # == Keyword Args ==
+    #
+    # Unspecified keyword arguments are treated as metadata to be sent to the
+    # server.
+    #
+    # @param method [String] the RPC method to call on the GRPC server
+    # @param req [Object] the request sent to the server
+    # @param marshal [Function] f(obj)->string that marshals requests
+    # @param unmarshal [Function] f(string)->obj that unmarshals responses
+    # @param timeout [Numeric] (optional) the max completion time in seconds
+    # @param deadline [Time] (optional) the time the request should complete
+    # @param parent [Core::Call] a prior call whose reserved metadata
+    #   will be propagated by this one.
+    # @param credentials [Core::CallCredentials] credentials to use when making
+    #   the call
+    # @param return_op [true|false] return an Operation if true
+    # @return [Object] the response received from the server
+    def request_response(method, req, marshal, unmarshal,
+                         deadline: nil,
+                         timeout: nil,
+                         return_op: false,
+                         parent: nil,
+                         credentials: nil,
+                         **kw)
+      c = new_active_call(method, marshal, unmarshal,
+                          deadline: deadline,
+                          timeout: timeout,
+                          parent: parent,
+                          credentials: credentials)
+      return c.request_response(req, **kw) unless return_op
+
+      # return the operation view of the active_call; define #execute as a
+      # new method for this instance that invokes #request_response.
+      op = c.operation
+      op.define_singleton_method(:execute) do
+        c.request_response(req, **kw)
+      end
+      op
+    end
+
+    # client_streamer sends a stream of requests to a GRPC server, and
+    # returns a single response.
+    #
+    # requests provides an 'iterable' of Requests. I.e. it follows Ruby's
+    # #each enumeration protocol. In the simplest case, requests will be an
+    # array of marshallable objects; in typical case it will be an Enumerable
+    # that allows dynamic construction of the marshallable objects.
+    #
+    # == Flow Control ==
+    # This is a blocking call.
+    #
+    # * it does not return until a response is received.
+    #
+    # * each requests is sent only when GRPC core's flow control allows it to
+    #   be sent.
+    #
+    # == Errors ==
+    # An RuntimeError is raised if
+    #
+    # * the server responds with a non-OK status
+    #
+    # * the deadline is exceeded
+    #
+    # == Return Value ==
+    #
+    # If return_op is false, the call consumes the requests and returns
+    # the response.
+    #
+    # If return_op is true, the call returns the response.
+    #
+    # == Keyword Args ==
+    #
+    # Unspecified keyword arguments are treated as metadata to be sent to the
+    # server.
+    #
+    # @param method [String] the RPC method to call on the GRPC server
+    # @param requests [Object] an Enumerable of requests to send
+    # @param marshal [Function] f(obj)->string that marshals requests
+    # @param unmarshal [Function] f(string)->obj that unmarshals responses
+    # @param timeout [Numeric] (optional) the max completion time in seconds
+    # @param deadline [Time] (optional) the time the request should complete
+    # @param return_op [true|false] return an Operation if true
+    # @param parent [Core::Call] a prior call whose reserved metadata
+    #   will be propagated by this one.
+    # @param credentials [Core::CallCredentials] credentials to use when making
+    #   the call
+    # @return [Object|Operation] the response received from the server
+    def client_streamer(method, requests, marshal, unmarshal,
+                        deadline: nil,
+                        timeout: nil,
+                        return_op: false,
+                        parent: nil,
+                        credentials: nil,
+                        **kw)
+      c = new_active_call(method, marshal, unmarshal,
+                          deadline: deadline,
+                          timeout: timeout,
+                          parent: parent,
+                          credentials: credentials)
+      return c.client_streamer(requests, **kw) unless return_op
+
+      # return the operation view of the active_call; define #execute as a
+      # new method for this instance that invokes #client_streamer.
+      op = c.operation
+      op.define_singleton_method(:execute) do
+        c.client_streamer(requests, **kw)
+      end
+      op
+    end
+
+    # server_streamer sends one request to the GRPC server, which yields a
+    # stream of responses.
+    #
+    # responses provides an enumerator over the streamed responses, i.e. it
+    # follows Ruby's #each iteration protocol.  The enumerator blocks while
+    # waiting for each response, stops when the server signals that no
+    # further responses will be supplied.  If the implicit block is provided,
+    # it is executed with each response as the argument and no result is
+    # returned.
+    #
+    # == Flow Control ==
+    # This is a blocking call.
+    #
+    # * the request is sent only when GRPC core's flow control allows it to
+    #   be sent.
+    #
+    # * the request will not complete until the server sends the final
+    #   response followed by a status message.
+    #
+    # == Errors ==
+    # An RuntimeError is raised if
+    #
+    # * the server responds with a non-OK status when any response is
+    # * retrieved
+    #
+    # * the deadline is exceeded
+    #
+    # == Return Value ==
+    #
+    # if the return_op is false, the return value is an Enumerator of the
+    # results, unless a block is provided, in which case the block is
+    # executed with each response.
+    #
+    # if return_op is true, the function returns an Operation whose #execute
+    # method runs server streamer call. Again, Operation#execute either
+    # calls the given block with each response or returns an Enumerator of the
+    # responses.
+    #
+    # == Keyword Args ==
+    #
+    # Unspecified keyword arguments are treated as metadata to be sent to the
+    # server.
+    #
+    # @param method [String] the RPC method to call on the GRPC server
+    # @param req [Object] the request sent to the server
+    # @param marshal [Function] f(obj)->string that marshals requests
+    # @param unmarshal [Function] f(string)->obj that unmarshals responses
+    # @param timeout [Numeric] (optional) the max completion time in seconds
+    # @param deadline [Time] (optional) the time the request should complete
+    # @param return_op [true|false]return an Operation if true
+    # @param parent [Core::Call] a prior call whose reserved metadata
+    #   will be propagated by this one.
+    # @param credentials [Core::CallCredentials] credentials to use when making
+    #   the call
+    # @param blk [Block] when provided, is executed for each response
+    # @return [Enumerator|Operation|nil] as discussed above
+    def server_streamer(method, req, marshal, unmarshal,
+                        deadline: nil,
+                        timeout: nil,
+                        return_op: false,
+                        parent: nil,
+                        credentials: nil,
+                        **kw,
+                        &blk)
+      c = new_active_call(method, marshal, unmarshal,
+                          deadline: deadline,
+                          timeout: timeout,
+                          parent: parent,
+                          credentials: credentials)
+      return c.server_streamer(req, **kw, &blk) unless return_op
+
+      # return the operation view of the active_call; define #execute
+      # as a new method for this instance that invokes #server_streamer
+      op = c.operation
+      op.define_singleton_method(:execute) do
+        c.server_streamer(req, **kw, &blk)
+      end
+      op
+    end
+
+    # bidi_streamer sends a stream of requests to the GRPC server, and yields
+    # a stream of responses.
+    #
+    # This method takes an Enumerable of requests, and returns and enumerable
+    # of responses.
+    #
+    # == requests ==
+    #
+    # requests provides an 'iterable' of Requests. I.e. it follows Ruby's
+    # #each enumeration protocol. In the simplest case, requests will be an
+    # array of marshallable objects; in typical case it will be an
+    # Enumerable that allows dynamic construction of the marshallable
+    # objects.
+    #
+    # == responses ==
+    #
+    # This is an enumerator of responses.  I.e, its #next method blocks
+    # waiting for the next response.  Also, if at any point the block needs
+    # to consume all the remaining responses, this can be done using #each or
+    # #collect.  Calling #each or #collect should only be done if
+    # the_call#writes_done has been called, otherwise the block will loop
+    # forever.
+    #
+    # == Flow Control ==
+    # This is a blocking call.
+    #
+    # * the call completes when the next call to provided block returns
+    # * [False]
+    #
+    # * the execution block parameters are two objects for sending and
+    #   receiving responses, each of which blocks waiting for flow control.
+    #   E.g, calles to bidi_call#remote_send will wait until flow control
+    #   allows another write before returning; and obviously calls to
+    #   responses#next block until the next response is available.
+    #
+    # == Termination ==
+    #
+    # As well as sending and receiving messages, the block passed to the
+    # function is also responsible for:
+    #
+    # * calling bidi_call#writes_done to indicate no further reqs will be
+    #   sent.
+    #
+    # * returning false if once the bidi stream is functionally completed.
+    #
+    # Note that response#next will indicate that there are no further
+    # responses by throwing StopIteration, but can only happen either
+    # if bidi_call#writes_done is called.
+    #
+    # To terminate the RPC correctly the block:
+    #
+    # * must call bidi#writes_done and then
+    #
+    #    * either return false as soon as there is no need for other responses
+    #
+    #    * loop on responses#next until no further responses are available
+    #
+    # == Errors ==
+    # An RuntimeError is raised if
+    #
+    # * the server responds with a non-OK status when any response is
+    # * retrieved
+    #
+    # * the deadline is exceeded
+    #
+    #
+    # == Keyword Args ==
+    #
+    # Unspecified keyword arguments are treated as metadata to be sent to the
+    # server.
+    #
+    # == Return Value ==
+    #
+    # if the return_op is false, the return value is an Enumerator of the
+    # results, unless a block is provided, in which case the block is
+    # executed with each response.
+    #
+    # if return_op is true, the function returns an Operation whose #execute
+    # method runs the Bidi call. Again, Operation#execute either calls a
+    # given block with each response or returns an Enumerator of the
+    # responses.
+    #
+    # @param method [String] the RPC method to call on the GRPC server
+    # @param requests [Object] an Enumerable of requests to send
+    # @param marshal [Function] f(obj)->string that marshals requests
+    # @param unmarshal [Function] f(string)->obj that unmarshals responses
+    # @param timeout [Numeric] (optional) the max completion time in seconds
+    # @param deadline [Time] (optional) the time the request should complete
+    # @param parent [Core::Call] a prior call whose reserved metadata
+    #   will be propagated by this one.
+    # @param credentials [Core::CallCredentials] credentials to use when making
+    #   the call
+    # @param return_op [true|false] return an Operation if true
+    # @param blk [Block] when provided, is executed for each response
+    # @return [Enumerator|nil|Operation] as discussed above
+    def bidi_streamer(method, requests, marshal, unmarshal,
+                      deadline: nil,
+                      timeout: nil,
+                      return_op: false,
+                      parent: nil,
+                      credentials: nil,
+                      **kw,
+                      &blk)
+      c = new_active_call(method, marshal, unmarshal,
+                          deadline: deadline,
+                          timeout: timeout,
+                          parent: parent,
+                          credentials: credentials)
+
+      return c.bidi_streamer(requests, **kw, &blk) unless return_op
+
+      # return the operation view of the active_call; define #execute
+      # as a new method for this instance that invokes #bidi_streamer
+      op = c.operation
+      op.define_singleton_method(:execute) do
+        c.bidi_streamer(requests, **kw, &blk)
+      end
+      op
+    end
+
+    private
+
+    # Creates a new active stub
+    #
+    # @param method [string] the method being called.
+    # @param marshal [Function] f(obj)->string that marshals requests
+    # @param unmarshal [Function] f(string)->obj that unmarshals responses
+    # @param parent [Grpc::Call] a parent call, available when calls are
+    #   made from server
+    # @param timeout [TimeConst]
+    def new_active_call(method, marshal, unmarshal,
+                        deadline: nil,
+                        timeout: nil,
+                        parent: nil,
+                        credentials: nil)
+      if deadline.nil?
+        deadline = from_relative_time(timeout.nil? ? @timeout : timeout)
+      end
+      call = @ch.create_call(@queue,
+                             parent, # parent call
+                             @propagate_mask, # propagation options
+                             method,
+                             nil, # host use nil,
+                             deadline)
+      call.set_credentials! credentials unless credentials.nil?
+      ActiveCall.new(call, @queue, marshal, unmarshal, deadline, started: false)
+    end
+  end
+end