protocols/remote_exec: add connect_global_rpc

artiq/protocols/remote_exec.py

@@ -4,7 +4,7 @@ import inspect
 from artiq.protocols.pc_rpc import simple_server_loop
 
 
-__all__ = ["RemoteExecServer", "RemoteExecClient", "simple_rexec_server_loop"]
+__all__ = ["RemoteExecServer", "simple_rexec_server_loop", "connect_global_rpc"]
 
 
 class RemoteExecServer:
@@ -29,3 +29,19 @@ def simple_rexec_server_loop(target_name, target, host, port,
         target_name + "_rexec": lambda: RemoteExecServer(initial_namespace)
     }
     simple_server_loop(targets, host, port, description)
+
+
+def connect_global_rpc(controller_rexec, host=None, port=3251,
+                       target="master_dataset_db", name="dataset_db"):
+    if host is None:
+        host = controller_rexec.get_local_host()
+    code = """
+if "{name}" not in controller_initial_namespace:
+    import atexit
+    from artiq.protocols.pc_rpc import Client
+
+    {name} = Client("{host}", {port}, "{target}")
+    atexit.register({name}.close_rpc)
+    controller_initial_namespace["{name}"] = {name}
+""".format(host=host, port=port, target=target, name=name)
+    controller_rexec.add_code(code)