tools/qvm-run: factor out actual process running into separate function

Pylint complains that main() is too long and that's indeed true. Factor
out single process call (together with all the prepartion) into separate
function and keep only common code in main().

qubesadmin/tools/qvm_run.py

@@ -138,24 +138,8 @@ def print_no_color(msg, file, color):
         print(msg, file=file)
 
 
-def main(args=None, app=None):
-    '''Main function of qvm-run tool'''
-    args = parser.parse_args(args, app=app)
-    if args.color_output is None and args.filter_esc:
-        args.color_output = '31'
-
-    if args.color_stderr is None and os.isatty(sys.stderr.fileno()):
-        args.color_stderr = 31
-
-    if len(args.domains) > 1 and args.passio and not args.localcmd:
-        parser.error('--passio cannot be used when more than 1 qube is chosen '
-                     'and no --localcmd is used')
-    if args.localcmd and not args.passio:
-        parser.error('--localcmd have no effect without --pass-io')
-    if args.color_output and not args.filter_esc:
-        parser.error('--color-output must be used with --filter-escape-chars')
-
-    retcode = 0
+def run_command_single(args, vm):
+    '''Handle a single VM to run the command in'''
     run_kwargs = {}
     if not args.passio:
         run_kwargs['stdout'] = subprocess.DEVNULL
@@ -180,6 +164,55 @@ def main(args=None, app=None):
         # simultaneous vchan connections
         run_kwargs['wait'] = False
 
+    copy_proc = None
+    local_proc = None
+    if args.service:
+        service = args.cmd
+    else:
+        service = 'qubes.VMShell'
+        if args.gui and args.dispvm:
+            service += '+WaitForSession'
+    proc = vm.run_service(service,
+        user=args.user,
+        **run_kwargs)
+    if not args.service:
+        proc.stdin.write(vm.prepare_input_for_vmshell(args.cmd))
+        proc.stdin.flush()
+    if args.localcmd:
+        local_proc = subprocess.Popen(args.localcmd,
+            shell=True,
+            stdout=proc.stdin,
+            stdin=proc.stdout)
+        # stdin is closed below
+        proc.stdout.close()
+    elif args.passio:
+        copy_proc = multiprocessing.Process(target=copy_stdin,
+            args=(proc.stdin,))
+        copy_proc.start()
+        # keep the copying process running
+    proc.stdin.close()
+    return proc, copy_proc, local_proc
+
+
+def main(args=None, app=None):
+    '''Main function of qvm-run tool'''
+    args = parser.parse_args(args, app=app)
+    if args.color_output is None and args.filter_esc:
+        args.color_output = '31'
+
+    if args.color_stderr is None and os.isatty(sys.stderr.fileno()):
+        args.color_stderr = 31
+
+    if len(args.domains) > 1 and args.passio and not args.localcmd:
+        parser.error('--passio cannot be used when more than 1 qube is chosen '
+                     'and no --localcmd is used')
+    if args.localcmd and not args.passio:
+        parser.error('--localcmd have no effect without --pass-io')
+    if args.color_output and not args.filter_esc:
+        parser.error('--color-output must be used with --filter-escape-chars')
+
+    retcode = 0
+
     verbose = args.verbose - args.quiet
     if args.passio:
         verbose -= 1
@@ -226,33 +259,10 @@ def main(args=None, app=None):
                         with contextlib.suppress(ProcessLookupError):
                             wait_session.send_signal(signal.SIGINT)
                         break
-                if args.service:
-                    service = args.cmd
-                else:
-                    service = 'qubes.VMShell'
-                    if args.gui and args.dispvm:
-                        service += '+WaitForSession'
-                proc = vm.run_service(service,
-                    user=args.user,
-                    **run_kwargs)
-                if not args.service:
-                    proc.stdin.write(vm.prepare_input_for_vmshell(args.cmd))
-                    proc.stdin.flush()
-                if args.localcmd:
-                    local_proc = subprocess.Popen(args.localcmd,
-                        shell=True,
-                        stdout=proc.stdin,
-                        stdin=proc.stdout)
-                    # stdin is closed below
-                    proc.stdout.close()
-                    procs.append((vm, local_proc))
-                elif args.passio:
-                    copy_proc = multiprocessing.Process(target=copy_stdin,
-                        args=(proc.stdin,))
-                    copy_proc.start()
-                    # keep the copying process running
-                proc.stdin.close()
+                proc, copy_proc, local_proc = run_command_single(args, vm)
                 procs.append((vm, proc))
+                if local_proc:
+                    procs.append((vm, local_proc))
             except qubesadmin.exc.QubesException as e:
                 if args.color_output:
                     sys.stdout.write('\033[0m')