log_dialog: display only last 1MB of log, force it plain text

qubesmanager/log_dialog.py

@@ -33,6 +33,8 @@ import qubesmanager.resources_rc
 
 from ui_logdlg import *
 
+# Display only this size of log
+LOG_DISPLAY_SIZE = 1024*1024
 
 class LogDialog(Ui_LogDialog, QDialog):
 
@@ -50,10 +52,17 @@ class LogDialog(Ui_LogDialog, QDialog):
         self.__init_log_text__()
 
     def __init_log_text__(self):
+        self.displayed_text = ""
         log = open(self.log_path)
-        self.displayed_text = log.read()
+        log.seek(0, os.SEEK_END)
+        if log.tell() > LOG_DISPLAY_SIZE:
+            self.displayed_text = "(Showing only last %d bytes of file)\n" % LOG_DISPLAY_SIZE
+            log.seek(-LOG_DISPLAY_SIZE, os.SEEK_END)
+        else:
+            log.seek(0, os.SEEK_SET)
+        self.displayed_text += log.read()
         log.close()
-        self.log_text.setText(self.displayed_text)
+        self.log_text.setPlainText(self.displayed_text)
 
 
     def copy_to_qubes_clipboard_triggered(self):