Daemon: Replace get_server with request.

This function performs a single RPC, and may raise a DaemonNotRunning exception.

electrum/daemon.py

@@ -53,6 +53,8 @@ from .logging import get_logger, Logger
 
 _logger = get_logger(__name__)
 
+class DaemonNotRunning(Exception):
+    pass
 
 def get_lockfile(config: SimpleConfig):
     return os.path.join(config.path, 'daemon')
@@ -74,14 +76,15 @@ def get_file_descriptor(config: SimpleConfig):
             return os.open(lockfile, os.O_CREAT | os.O_EXCL | os.O_WRONLY, 0o644)
         except OSError:
             pass
-        server = get_server(config)
-        if server is not None:
-            return
+        try:
+            request(config, 'ping')
+            return None
+        except DaemonNotRunning:
             # Couldn't connect; remove lockfile and try again.
             remove_lockfile(lockfile)
 
 
-def get_server(config: SimpleConfig) -> Optional[jsonrpclib.Server]:
+def request(config: SimpleConfig, endpoint, *args, **kwargs):
     lockfile = get_lockfile(config)
     while True:
         create_time = None
@@ -95,14 +98,17 @@ def get_server(config: SimpleConfig) -> Optional[jsonrpclib.Server]:
             else:
                 server_url = 'http://%s:%s@%s:%d' % (
                     rpc_user, rpc_password, host, port)
+        except Exception:
+            raise DaemonNotRunning()
         server = jsonrpclib.Server(server_url)
-            # Test daemon is running
-            server.ping()
-            return server
-        except Exception as e:
-            _logger.info(f"failed to connect to JSON-RPC server: {e}")
+        try:
+            # run request
+            f = getattr(server, endpoint)
+            return f(*args, **kwargs)
+        except ConnectionRefusedError:
+            _logger.info(f"failed to connect to JSON-RPC server")
             if not create_time or create_time < time.time() - 1.0:
-            return None
+                raise DaemonNotRunning()
         # Sleep a bit and try again; it might have just been started
         time.sleep(1.0)
 

run_electrum

@@ -364,8 +364,7 @@ if __name__ == '__main__':
             d.init_gui(config, plugins)
             sys.exit(0)
         else:
-            server = daemon.get_server()
-            result = server.gui(config_options)
+            result = daemon.request(config, 'gui', config_options)
 
     elif cmdname == 'daemon':
         subcommand = config.get('subcommand')
@@ -405,27 +404,25 @@ if __name__ == '__main__':
                 d.join()
                 sys.exit(0)
             else:
-                server = daemon.get_server(config)
-                result = server.daemon(config_options)
-        else:
-            server = daemon.get_server(config)
-            if server is not None:
-                result = server.daemon(config_options)
+                result = daemon.request(config, 'daemon', config_options)
         else:
+            try:
+                result = daemon.request(config, 'daemon', config_options)
+            except daemon.DaemonNotRunning:
                 print_msg("Daemon not running")
                 sys.exit(1)
     else:
         # command line
-        server = daemon.get_server(config)
-        init_cmdline(config_options, server)
-        if server is not None:
-            result = server.run_cmdline(config_options)
-        else:
+        try:
+            init_cmdline(config_options, True)
+            result = daemon.request(config, 'run_cmdline', config_options)
+        except daemon.DaemonNotRunning:
             cmd = known_commands[cmdname]
             if cmd.requires_network:
                 print_msg("Daemon not running; try 'electrum daemon start'")
                 sys.exit(1)
             else:
+                init_cmdline(config_options, False)
                 plugins = init_plugins(config, 'cmdline')
                 result = run_offline_command(config, config_options, plugins)
                 # print result