Adding (optional) file monitoring functionality to automatically reload pecan apps when .py files change (similar to paster --reload server config.ini). Now in your project, you can do:

pecan.conf.app = {'reload': True, ...}

Additionally, the pecan quick start template has been configured to auto-reload by default.

.gitignore

@@ -1 +1,2 @@
 pecan.egg-info
+*.pyc

pecan/monitor.py

@@ -0,0 +1,77 @@
+import sys, os
+import subprocess
+
+class MonitorableProcess(object):
+    
+    _reloader_environ_key = 'PYTHON_RELOADER_SHOULD_RUN'
+    
+    def start_monitoring(self):
+        if os.environ.get(self._reloader_environ_key):
+            from paste import reloader
+            reloader.install()
+        else:
+            return self.restart_with_reloader()        
+    
+    def restart_with_reloader(self):
+        print 'Starting subprocess with file monitor'
+        while 1:
+            args = [self.quote_first_command_arg(sys.executable)] + sys.argv
+            new_environ = os.environ.copy()
+            new_environ[self._reloader_environ_key] = 'true'
+            proc = None
+            try:
+                try:
+                    _turn_sigterm_into_systemexit()
+                    proc = subprocess.Popen(args, env=new_environ)
+                    exit_code = proc.wait()
+                    proc = None
+                except KeyboardInterrupt:
+                    print '^C caught in monitor process'
+                    raise
+            finally:
+                if (proc is not None
+                    and hasattr(os, 'kill')):
+                    import signal
+                    try:
+                        os.kill(proc.pid, signal.SIGTERM)
+                    except (OSError, IOError):
+                        pass
+            
+            # Reloader always exits with code 3; but if we are
+            # a monitor, any exit code will restart
+            if exit_code != 3:
+                return exit_code
+            print '-'*20, 'Restarting', '-'*20
+            
+    def quote_first_command_arg(self, arg):
+        """
+        There's a bug in Windows when running an executable that's
+        located inside a path with a space in it.  This method handles
+        that case, or on non-Windows systems or an executable with no
+        spaces, it just leaves well enough alone.
+        """
+        if (sys.platform != 'win32'
+            or ' ' not in arg):
+            # Problem does not apply:
+            return arg
+        try:
+            import win32api
+        except ImportError:
+            raise ValueError(
+                "The executable %r contains a space, and in order to "
+                "handle this issue you must have the win32api module "
+                "installed" % arg)
+        arg = win32api.GetShortPathName(arg)
+        return arg            
+            
+def _turn_sigterm_into_systemexit():
+    """
+    Attempts to turn a SIGTERM exception into a SystemExit exception.
+    """
+    try:
+        import signal
+    except ImportError:
+        return
+    def handle_term(signo, frame):
+        raise SystemExit
+    signal.signal(signal.SIGTERM, handle_term)

pecan/pecan.py

@@ -1,3 +1,5 @@
+from configuration      import _runtime_conf
+from monitor            import MonitorableProcess
 from templating         import renderers
 from routing            import lookup_controller
 
@@ -50,7 +52,7 @@ def error_for(field):
     return request.validation_error.error_dict.get(field, '')
 
 
-class Pecan(object):
+class Pecan(MonitorableProcess):
     def __init__(self, root, 
                  renderers        = renderers, 
                  default_renderer = 'kajiki', 
@@ -62,6 +64,10 @@ class Pecan(object):
         self.default_renderer = default_renderer
         self.hooks            = hooks
         self.template_path    = template_path
+        
+        MonitorableProcess.__init__(self)
+        if getattr(_runtime_conf.app, 'reload', False) is True:
+            self.start_monitoring()
     
     def get_content_type(self, format):
         return {

templates/project/config.py_tmpl

@@ -12,6 +12,7 @@ app = {
     'root' : RootController(),
     'static_root' : 'public', 
     'template_path' : '${egg}/templates',
+    'reload': True,
     'debug' : True 
 }