Reload watched (sub)modules automatically

Adds a new step, ReloadModules, which reloads all watched modules except for the init module.

This step needs to know which modules have changed, which is currently only available in the main loops variables (new_changed, last_changed), so I pass this information to the step if it's named "ReloadModules". Other alternatives could be some global state, or passing some general state to all the steps.

Author: tingstad

hotload.py

@@ -46,6 +46,21 @@ def _file_changed(f):
 def _all_file_changes(filepaths):
     return {path: _file_changed(path) for path in filepaths}
 
+def _changed_modules(new_changed, last_changed):
+    list = []
+    if last_changed is None:
+        return list
+    modules = {}
+    for module in sys.modules.copy().values():
+        file = getattr(module, '__file__', None)
+        if file is not None:
+            modules[file] = module
+    for path in new_changed:
+        if new_changed[path] != last_changed[path]:
+            module = modules.get(path, None)
+            if module is not None:
+                list.append(module)
+    return list
 
 def listfiles(folder, ext=""):
     fs = list()
@@ -135,6 +150,13 @@ class ClearTerminal(Runnable):
     def run(self):
         os.system("cls" if os.name == "nt" else "clear")
 
+class ReloadModules(Runnable):
+    def __init__(self, module):
+        self.main_module = module
+    def run(self, modules):
+        for module in modules:
+            if module != self.main_module:
+                _reload_module(module)
 
 def hotload(watch, steps, waittime_ms=1.0 / 144):
     """Hotload that code!"""
@@ -148,18 +170,25 @@ def hotload(watch, steps, waittime_ms=1.0 / 144):
     # Take note of when files were last changed before we start reloading
     last_changed = None
 
+    is_module_reloader = lambda step: type(step).__name__ == "ReloadModules"
+    do_reload_modules = bool(list(filter(is_module_reloader, steps)))
+
     # Begin the loop! Each Runner is responsible for handling its own exceptions.
     while True:
         new_changed = _all_file_changes(watchfiles)
         if last_changed == new_changed:
             time.sleep(waittime_ms)
         else:
             reload_begin_ms = time.time() * 1000
+            changed_modules = _changed_modules(new_changed, last_changed) if do_reload_modules else []
             last_changed = new_changed
             try:
                 for step in steps:
                     try:
-                        step.run()
+                        if is_module_reloader(step):
+                            step.run(changed_modules)
+                        else:
+                            step.run()
                     except KeyboardInterrupt:
                         raise
                     except:
@@ -210,7 +239,7 @@ def main():
     print()
     print("  ls *py | hotload hello.py")
 
-    watchfiles = [f.strip() for f in sys.stdin.readlines()]
+    watchfiles = [os.path.normpath(os.path.join(os.getcwd(), f.strip())) for f in sys.stdin.readlines()]
 
     if not watchfiles:
         print("Error: no watch files specified.")
@@ -227,7 +256,7 @@ def main():
 
     conf = {
         "watch": [watchfiles],
-        "steps": [ClearTerminal(), reloaded_module],
+        "steps": [ClearTerminal(), ReloadModules(reloaded_module.module), reloaded_module],
     }
 
     hotload(**conf)
@@ -237,3 +266,4 @@ def main():
 
 if __name__ == "__main__":
     main()
+