Fix GRPC server blocking interrupt of RSpec

The `GRPC::RpcServer` was run with `run_till_terminated_or_interrupted`
listening on the `QUIT`, `INT` and `TERM` signals. This however replaced
the original signal traps from RSpec, preventing its interruption after
the GRPC server was started.

To fix this, the signal traps are moved into the entrypoint, so they
are not registered during RSpec and RSpec continues to handle the
signals and shutting down the server.

Author: Taucher2003

bin/grpc_server

@@ -3,4 +3,24 @@
 
 require_relative '../config/environment'
 
-Sagittarius::Grpc::Launcher.new.start_blocking
+launcher = Sagittarius::Grpc::Launcher.new
+
+stop_signals = %w[QUIT INT TERM]
+stop_read, stop_write = IO.pipe
+
+stop_signals.each do |signal|
+  Signal.trap(signal) do
+    stop_write.puts(signal)
+  end
+end
+
+launcher.start
+
+while (readable_io = IO.select([stop_read]))
+  signal = readable_io.first[0].gets.strip
+
+  if stop_signals.include?(signal)
+    launcher.stop
+    break
+  end
+end

lib/sagittarius/grpc/launcher.rb

@@ -7,7 +7,7 @@ class Launcher
 
       HOST = '0.0.0.0:50051'
 
-      def load
+      def create_server
         @server = GRPC::RpcServer.new(interceptors: [
           Sagittarius::Middleware::Grpc::Context.new,
           Sagittarius::Middleware::Grpc::Logger.new,
@@ -26,26 +26,21 @@ def load
       end
 
       def run_server!
-        load if @server.nil?
+        create_server if @server.nil?
         logger.info('Running server')
-        @server.run_till_terminated_or_interrupted(%w[QUIT INT TERM])
+        @server.run_till_terminated_or_interrupted([])
       end
 
       def run_stream_listener!
         GrpcStreamHandler.listen!
       end
 
       def start
-        load
+        create_server
         @stream_thread = Thread.new { run_stream_listener! }
         @server_thread = Thread.new { run_server! }
       end
 
-      def start_blocking
-        start
-        @server_thread.join # Wait for the server thread to finish because the program would end otherwise
-      end
-
       def stop
         @server.stop
         @server_thread.join