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# Copyright 2015 gRPC authors.
#
# 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.
require_relative '../grpc'
# GRPC contains the General RPC module.
module GRPC
# RpcDesc is a Descriptor of an RPC method.
class RpcDesc < Struct.new(:name, :input, :output, :marshal_method,
:unmarshal_method)
include Core::StatusCodes
# Used to wrap a message class to indicate that it needs to be streamed.
class Stream
attr_accessor :type
def initialize(type)
@type = type
end
end
# @return [Proc] { |instance| marshalled(instance) }
def marshal_proc
proc { |o| o.class.send(marshal_method, o).to_s }
end
# @param [:input, :output] target determines whether to produce the an
# unmarshal Proc for the rpc input parameter or
# its output parameter
#
# @return [Proc] An unmarshal proc { |marshalled(instance)| instance }
def unmarshal_proc(target)
fail ArgumentError unless [:input, :output].include?(target)
unmarshal_class = send(target)
unmarshal_class = unmarshal_class.type if unmarshal_class.is_a? Stream
proc { |o| unmarshal_class.send(unmarshal_method, o) }
end
def handle_request_response(active_call, mth, inter_ctx)
req = active_call.read_unary_request
call = active_call.single_req_view
inter_ctx.intercept!(
:request_response,
method: mth,
call: call,
request: req
) do
resp = mth.call(req, call)
active_call.server_unary_response(
resp,
trailing_metadata: active_call.output_metadata
)
end
end
def handle_client_streamer(active_call, mth, inter_ctx)
call = active_call.multi_req_view
inter_ctx.intercept!(
:client_streamer,
method: mth,
call: call
) do
resp = mth.call(call)
active_call.server_unary_response(
resp,
trailing_metadata: active_call.output_metadata
)
end
end
def handle_server_streamer(active_call, mth, inter_ctx)
req = active_call.read_unary_request
call = active_call.single_req_view
inter_ctx.intercept!(
:server_streamer,
method: mth,
call: call,
request: req
) do
replies = mth.call(req, call)
replies.each { |r| active_call.remote_send(r) }
send_status(active_call, OK, 'OK', active_call.output_metadata)
end
end
##
# @param [GRPC::ActiveCall] active_call
# @param [Method] mth
# @param [Array<GRPC::InterceptionContext>] inter_ctx
#
def handle_bidi_streamer(active_call, mth, inter_ctx)
active_call.run_server_bidi(mth, inter_ctx)
send_status(active_call, OK, 'OK', active_call.output_metadata)
end
##
# @param [GRPC::ActiveCall] active_call The current active call object
# for the request
# @param [Method] mth The current RPC method being called
# @param [GRPC::InterceptionContext] inter_ctx The interception context
# being executed
#
def run_server_method(active_call, mth, inter_ctx = InterceptionContext.new)
# While a server method is running, it might be cancelled, its deadline
# might be reached, the handler could throw an unknown error, or a
# well-behaved handler could throw a StatusError.
if request_response?
handle_request_response(active_call, mth, inter_ctx)
elsif client_streamer?
handle_client_streamer(active_call, mth, inter_ctx)
elsif server_streamer?
handle_server_streamer(active_call, mth, inter_ctx)
else # is a bidi_stream
handle_bidi_streamer(active_call, mth, inter_ctx)
end
rescue BadStatus => e
# this is raised by handlers that want GRPC to send an application error
# code and detail message and some additional app-specific metadata.
GRPC.logger.debug("app err:#{active_call}, status:#{e.code}:#{e.details}")
send_status(active_call, e.code, e.details, e.metadata)
rescue Core::CallError => e
# This is raised by GRPC internals but should rarely, if ever happen.
# Log it, but don't notify the other endpoint..
GRPC.logger.warn("failed call: #{active_call}\n#{e}")
rescue Core::OutOfTime
# This is raised when active_call#method.call exceeds the deadline
# event. Send a status of deadline exceeded
GRPC.logger.warn("late call: #{active_call}")
send_status(active_call, DEADLINE_EXCEEDED, 'late')
rescue StandardError, NotImplementedError => e
# This will usuaally be an unhandled error in the handling code.
# Send back a UNKNOWN status to the client
#
# Note: this intentionally does not map NotImplementedError to
# UNIMPLEMENTED because NotImplementedError is intended for low-level
# OS interaction (e.g. syscalls) not supported by the current OS.
GRPC.logger.warn("failed handler: #{active_call}; sending status:UNKNOWN")
GRPC.logger.warn(e)
send_status(active_call, UNKNOWN, "#{e.class}: #{e.message}")
end
def assert_arity_matches(mth)
# A bidi handler function can optionally be passed a second
# call object parameter for access to metadata, cancelling, etc.
if bidi_streamer?
if mth.arity != 2 && mth.arity != 1
fail arity_error(mth, 2, "should be #{mth.name}(req, call) or " \
"#{mth.name}(req)")
end
elsif request_response? || server_streamer?
if mth.arity != 2
fail arity_error(mth, 2, "should be #{mth.name}(req, call)")
end
else
if mth.arity != 1
fail arity_error(mth, 1, "should be #{mth.name}(call)")
end
end
end
def request_response?
!input.is_a?(Stream) && !output.is_a?(Stream)
end
def client_streamer?
input.is_a?(Stream) && !output.is_a?(Stream)
end
def server_streamer?
!input.is_a?(Stream) && output.is_a?(Stream)
end
def bidi_streamer?
input.is_a?(Stream) && output.is_a?(Stream)
end
def arity_error(mth, want, msg)
"##{mth.name}: bad arg count; got:#{mth.arity}, want:#{want}, #{msg}"
end
def send_status(active_client, code, details, metadata = {})
details = 'Not sure why' if details.nil?
GRPC.logger.debug("Sending status #{code}:#{details}")
active_client.send_status(code, details, code == OK, metadata: metadata)
rescue StandardError => e
GRPC.logger.warn("Could not send status #{code}:#{details}")
GRPC.logger.warn(e)
end
end
end
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