function.rb

# MIT License
# 
# Copyright (c) 2018, Zane Claes
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in all
# copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.

module Gateway
  # Storage for an actual function definition.
  # Implements a `call` method so that it may be invoked with a simple hash of params.
  class Function
    attr_reader :service_name, :name, :rpc_desc

    def initialize(service_name, service_stub, rpc_desc)
      @service_name = service_name
      @service_stub = service_stub
      @rpc_desc = rpc_desc
      @name = GRPC::GenericService.underscore(rpc_desc.name.to_s).to_sym
    end

    def to_s
      "<GrpcFunction #{service_name}##{name} >"
    end

    def call(params = {}, metadata = {})
      @service_stub.send(name, arg(params || {}), metadata: metadata).to_hash
    end

    private

    # Build arguments to a func
    def arg(params)
      rpc_desc.input.decode_json(params.to_json)
    end
  end
end