run subprocesses in threads

bin/simple-apt-update

@@ -1,5 +1,8 @@
 #!/usr/bin/env python3
 
+import re
+import queue
+import threading
 import gi
 import html
 import logging
@@ -12,18 +15,30 @@ import sys
 gi.require_version('Gdk', '3.0')
 gi.require_version('Gtk', '3.0')
 
-try:
-    from gi.repository import Gtk
-except ImportError:
-    logging.error("Could not import Gtk")
-    sys.exit(1)
-
 try:
     from gi.repository import Gio
 except ImportError:
     logging.error("Could not import Gio")
     sys.exit(1)
 
+# try:
+#     from gi.repository import GObject
+# except ImportError:
+#     logging.error("Could not import GObject")
+#     sys.exit(1)
+
+try:
+    from gi.repository import GLib
+except ImportError:
+    logging.error("Could not import Gio")
+    sys.exit(1)
+
+try:
+    from gi.repository import Gtk
+except ImportError:
+    logging.error("Could not import Gtk")
+    sys.exit(1)
+
 
 class UpdateWindow(Gtk.ApplicationWindow):
     def clear(self):
@@ -81,14 +96,17 @@ class UpdateWindow(Gtk.ApplicationWindow):
     def insert(self, text, iter):
         self.buffer.insert(iter, text + "\n")
 
-    def run(self, args, ignore_stderr=False, output_msg=None,
+    def execute(self, args, ignore_stderr=False, output_msg=None,
                 empty_msg=None, env={}):
         self.lock()
         self.clear()
         self.prepend_mesg(
             "INFO",
             "Running command \"%s\" ..." % " ".join(args))
+        thread = threading.Thread(target=self.run, args=(args, env,))
+        thread.start()
 
+    def run(self, args, env={}):
         p = subprocess.Popen(
             args, stdout=subprocess.PIPE, stderr=subprocess.PIPE, shell=False,
             env=dict(os.environ, **env))
@@ -97,8 +115,6 @@ class UpdateWindow(Gtk.ApplicationWindow):
         sel.register(p.stdout, selectors.EVENT_READ)
         sel.register(p.stderr, selectors.EVENT_READ)
         done = False
-        output = False
-        error = False
 
         while not done:
             for key, _ in sel.select():
@@ -106,39 +122,17 @@ class UpdateWindow(Gtk.ApplicationWindow):
 
                 if data:
                     if key.fileobj is p.stdout:
-                        logging.debug("STDOUT: " + data)
+                        self.stdout_queue.put(data)
-                        self.append_mesg("STDOUT", data)
+                    else:
-                        output = True
+                        self.stderr_queue.put(data)
-                    elif not ignore_stderr:
-                        logging.debug("STDERR: " + data)
-                        self.append_mesg("STDERR", data)
 
                 exit_code = p.poll()
 
                 if exit_code is not None:
-                    if exit_code != 0:
+                    self.stdout_queue.put("EXIT %d" % exit_code)
-                        self.append_mesg(
-                            "ERROR",
-                            "apt-get exit code: %d\n" % exit_code
-                        )
-                        error = True
-
                     done = True
                     break
 
-        self.unlock()
-
-        if error:
-            return False
-        else:
-            if output:
-                if output_msg is not None:
-                    self.prepend_mesg("INFO", output_msg)
-            elif empty_msg is not None:
-                self.append_mesg("INFO", empty_msg)
-
-            return True
-
     def lock(self):
         self.update_button.set_sensitive(False)
         self.upgrade_button.set_sensitive(False)
@@ -154,7 +148,7 @@ class UpdateWindow(Gtk.ApplicationWindow):
     def upgrade(self):
         args = ['/usr/bin/apt-get', '-yqq', 'full-upgrade']
         env = {'DEBIAN_FRONTEND': 'noninteractive'}
-        self.run(
+        self.execute(
             args,
             env=env,
             empty_msg="No package upgrades were performed.")
@@ -165,14 +159,14 @@ class UpdateWindow(Gtk.ApplicationWindow):
     def update(self):
         args = ['/usr/bin/apt-get', '-y', 'update']
         env = {'DEBIAN_FRONTEND': 'noninteractive'}
-        self.run(args, env=env)
+        self.execute(args, env=env)
 
     def on_update(self, *args):
         self.update()
 
     def list(self):
         args = ['/usr/bin/apt', '-qq', 'list', '--upgradable']
-        self.run(
+        self.execute(
             args,
             ignore_stderr=True,
             output_msg="Found the following package upgrades:",
@@ -184,11 +178,39 @@ class UpdateWindow(Gtk.ApplicationWindow):
     def on_quit(self, *args):
         self.application.quit()
 
+    def update_buffer(self):
+        try:
+            text = self.stdout_queue.get(block=False)
+            self.append_mesg("STDOUT", text)
+            match = re.fullmatch(r'EXIT (\d+)', text)
+            if match is not None:
+                exit_code = int(match.group(1))
+                if exit_code != 0:
+                    self.append_mesg(
+                        "ERROR",
+                        "Command exited with code %d" % exit_code)
+
+                self.unlock()
+
+        except queue.Empty:
+            pass
+
+        try:
+            text = self.stderr_queue.get(block=False)
+            self.append_mesg("STDERR", text)
+        except queue.Empty:
+            pass
+
+        return True
+
     def __init__(self, application):
         super(UpdateWindow, self).__init__(
             application=application,
             title="Simple APT Update")
         self.application = application
+        self.stdout_queue = queue.Queue()
+        self.stderr_queue = queue.Queue()
+        GLib.timeout_add(100, self.update_buffer)
         self.init_ui()
 
     def init_ui(self):
@@ -282,8 +304,6 @@ class SimpleAptUpdate(Gtk.Application):
 
         self.window.present()
         self.window.show_all()
-        self.window.update()
-        self.window.list()
 
 
 def main():