force_exit() to make exit work with all `fdroid build` conditions

The build command has to use some threading stuff to handle the timeout and
locks.  This seems to prevent the command from exiting, unless this hack is
used.

fdroid

@@ -149,9 +149,7 @@ def main():
         sys.exit(1)
     except KeyboardInterrupt:
         print('')
-        sys.stdout.flush()
-        sys.stderr.flush()
-        os._exit(1)
+        fdroidserver.common.force_exit(1)
     # These should only be unexpected crashes due to bugs in the code
     # str(e) often doesn't contain a reason, so just show the backtrace
     except Exception as e:

fdroidserver/build.py

@@ -1148,7 +1148,7 @@ def main():
                     appid, reason))
                 if options.stop:
                     logging.debug("Error encoutered, stopping by user request.")
-                    sys.exit(1)
+                    common.force_exit(1)
                 failed_apps[appid] = vcse
                 wikilog = str(vcse)
             except FDroidException as e:
@@ -1163,7 +1163,7 @@ def main():
                 logging.error("Could not build app %s: %s" % (appid, e))
                 if options.stop:
                     logging.debug("Error encoutered, stopping by user request.")
-                    sys.exit(1)
+                    common.force_exit(1)
                 failed_apps[appid] = e
                 wikilog = e.get_wikitext()
             except Exception as e:
@@ -1171,7 +1171,7 @@ def main():
                     appid, traceback.format_exc()))
                 if options.stop:
                     logging.debug("Error encoutered, stopping by user request.")
-                    sys.exit(1)
+                    common.force_exit(1)
                 failed_apps[appid] = e
                 wikilog = str(e)
 
@@ -1238,7 +1238,7 @@ def main():
 
                 if not os.path.isdir(repo_dir):
                     logging.critical("directory does not exists '{path}'".format(path=repo_dir))
-                    sys.exit(1)
+                    common.force_exit(1)
 
                 logging.info("Performing Drozer scan on {0}.".format(app))
                 docker.perform_drozer_scan(apk_path, app.id, repo_dir)
@@ -1289,9 +1289,7 @@ def main():
         newpage.save('#REDIRECT [[' + wiki_page_path + ']]', summary='Update redirect')
 
     # hack to ensure this exits, even is some threads are still running
-    sys.stdout.flush()
-    sys.stderr.flush()
-    os._exit(0)
+    common.force_exit()
 
 
 if __name__ == "__main__":

fdroidserver/common.py

@@ -3424,3 +3424,16 @@ def calculate_math_string(expr):
         raise SyntaxError("could not parse expression '{expr}', "
                           "only basic math operations are allowed (+, -, *)"
                           .format(expr=expr))
+
+
+def force_exit(exitvalue=0):
+    """force exit when thread operations could block the exit
+
+    The build command has to use some threading stuff to handle the
+    timeout and locks.  This seems to prevent the command from
+    exiting, unless this hack is used.
+
+    """
+    sys.stdout.flush()
+    sys.stderr.flush()
+    os._exit(exitvalue)