build: make per-build hard time limit customizable

Add "timeout=n" metadata field that overrides build timeout (in seconds).
The default is 7200, i.e. 2 hours.

fdroidserver/build.py

@@ -913,9 +913,9 @@ def trybuild(app, build, build_dir, output_dir, log_dir, also_check_dir,
     return True
 
 
-def force_halt_build():
+def force_halt_build(timeout):
     """Halt the currently running Vagrant VM, to be called from a Timer"""
-    logging.error(_('Force halting build after timeout!'))
+    logging.error(_('Force halting build after {0} sec timeout!').format(timeout))
     timeout_event.set()
     vm = vmtools.get_build_vm('builder')
     vm.halt()
@@ -1093,8 +1093,15 @@ def main():
             if time.time() > endtime:
                 max_build_time_reached = True
                 break
-            if options.server:  # enable watchdog timer
-                timer = threading.Timer(7200, force_halt_build)
+
+            # Enable watchdog timer (2 hours by default).
+            if build.timeout is None:
+                timeout = 7200
+            else:
+                timeout = int(build.timeout)
+            if options.server and timeout > 0:
+                logging.debug(_('Setting {0} sec timeout for this build').format(timeout))
+                timer = threading.Timer(timeout, force_halt_build, [timeout])
                 timer.start()
             else:
                 timer = None

fdroidserver/metadata.py

@@ -206,6 +206,7 @@ def fieldtype(name):
 build_flags_order = [
     'disable',
     'commit',
+    'timeout',
     'subdir',
     'submodules',
     'sudo',
@@ -248,6 +249,7 @@ class Build(dict):
         super().__init__()
         self.disable = False
         self.commit = None
+        self.timeout = None
         self.subdir = None
         self.submodules = False
         self.sudo = ''
@@ -347,6 +349,7 @@ flagtypes = {
     'forcevercode': TYPE_BOOL,
     'novcheck': TYPE_BOOL,
     'antifeatures': TYPE_LIST,
+    'timeout': TYPE_INT,
 }
 
 
@@ -1208,6 +1211,8 @@ def parse_txt_metadata(mf, app):
             build[pk] = pv
         elif t == TYPE_BOOL:
             build[pk] = _decode_bool(pv)
+        elif t == TYPE_INT:
+            build[pk] = int(pv)
 
     def parse_buildline(lines):
         v = "".join(lines)