rev 0.6

variables to ease integration with
"cmd" module.

VERSION

@@ -1 +1 @@
-0.1
+0.6

pyproject.toml

@@ -15,9 +15,7 @@ classifiers = [
     "License :: OSI Approved :: CeCILL-C",
     "Operating System :: OS Independent",
 ]
-dependencies = [
-    "systemd-python",
-]
+dependencies = [ ]
 dynamic = ["version"]
 
 [project.urls]

src/appengine/__init__.py

@@ -5,14 +5,14 @@ import sys
 import traceback
 from configparser import ConfigParser
 import logging
-from systemd import journal
 import inspect
 from enum import Enum, auto
+import signal
 from importlib import import_module
 from threading import Thread, Lock
 
 import inspect
-from threading import Thread
+from threading import Thread, Event
 
 
 def is_number(s):
@@ -48,13 +48,15 @@ class AppEngineException(Exception):
     def __init__(self, error: AEErrs, mesg=None) -> None:
         if mesg is None:
             self.mesg = str(error)
+        else:
+            self.mesg = mesg
         super().__init__(self.mesg)
         self.value = error.value
 
 
 class Commands(Thread):
     defmod = None
-    precmd = "cmd_"
+    prefcmd = "cmd_"
 
     def __init__(self, config: ConfigParser, log: logging.Handler) -> None:
         super().__init__()
@@ -62,6 +64,7 @@ class Commands(Thread):
         self.cmods = {}
         self.config = config
         self.log = log
+        self.stop_all_event = None
         self.stopped = False
         self.nickname = None
         if not (self.config is None):
@@ -103,6 +106,12 @@ class Commands(Thread):
     def stop(self):
         self.stopped = True
 
+    def free(self):
+        """ Virtual method used to clean resources for all Commands
+        when the application is exited.
+        """
+        pass
+
     def list_modules(self):
         success = True
         ret = "List of modules:\n"
@@ -110,15 +119,24 @@ class Commands(Thread):
             ret = ret + "  " + module + "\n"
         return success, ret.strip()
 
+    def help_module(self, module, *args):
+        if module in self.cmods.keys():
+            if len(args) > 0:
+                return self.cmods[module].cmd_help(args[0])
+            else:
+                return self.cmods[module].cmd_help()
+        else:
+            return "No module with this name"
+
     def _execute_command(self, method: str, *args, **kwargs) -> tuple:
         success = False
         ret = (AEErrs.INTERNAL_ERROR.value, "function not found")
-        if hasattr(self, self.precmd + method) and inspect.ismethod(
-            getattr(self, self.precmd + method)
+        if hasattr(self, self.prefcmd + method) and inspect.ismethod(
+            getattr(self, self.prefcmd + method)
         ):
             self.lock.acquire()
             try:
-                f = getattr(self, self.precmd + method)
+                f = getattr(self, self.prefcmd + method)
                 ret = f(*args, **kwargs)
                 success = True
                 self.log.info(
@@ -158,7 +176,28 @@ class Commands(Thread):
 
         if module == "":
             if method == 'help':
-                return self.list_modules()
+                # No argument was given to the help function
+                if len(args) == 0 and len(kwargs) == 0:
+                    msg  = "Type 'help <module>' to have the list of module's functions.\n"
+                    msg += "Type 'help <module>.<function>' to documentation of a specific function.\n"
+                    success, ret = self.list_modules()
+                    return success, msg + ret
+                else:
+                    # 1 argument has been provided
+                    if len(args) > 0:
+                        arg = args[0]
+                    else:
+                        arg = list(kwargs.keys())[0]
+                    spl = arg.split(".", 1)
+
+                    # help <module>
+                    if len(spl) == 1:
+                        module = arg
+                    # help <module>.<method>
+                    else:
+                        module = spl[0]
+                        args = [spl[1]]
+                        kwargs = {}
             else:
                 module = self.defmod
 
@@ -171,6 +210,10 @@ class Commands(Thread):
 
         return self.cmods[module]._execute_command(method, *args, **kwargs)
 
+    def stop_all(self):
+        if self.stop_all_event is not None:
+            self.stop_all_event.set()
+
     def cmd_help(self, *args, **kwargs):
         """Help of module commands.
         Params:
@@ -181,12 +224,12 @@ class Commands(Thread):
 
         if len(args) == 0:
             cmds = inspect.getmembers(self, predicate=inspect.ismethod)
-            cmds = [x for x in cmds if x[0].startswith(self.precmd)]
+            cmds = [x for x in cmds if x[0].startswith(self.prefcmd)]
             for m in cmds:
-                ret = ret + m[0][len(self.precmd):] + "\n"
+                ret = ret + m[0][len(self.prefcmd):] + "\n"
         else:
             if isinstance(args[0], str):
-                cmd = self.precmd + args[0]
+                cmd = self.prefcmd + args[0]
                 c = getattr(self, cmd, None)
                 if c:
                     r = inspect.getdoc(c)
@@ -202,20 +245,21 @@ class Commands(Thread):
 
 
 class CommandsLoader:
-    def __init__(self, config: ConfigParser, log: logging.Handler, modpath: str):
+    def __init__(self, stop_event: Event, config: ConfigParser, log: logging.Handler, modpath: str):
         self.config = config
         self.modpath = modpath
         sys.path.append(os.path.join(modpath))
         Commands.defmod = self.config["general"].get("default")
-        precmd = self.config["general"].get("methods_prefix")
-        if not precmd is None:
-            Commands.precmd = precmd
-        self.precmds = "cmds_"
-        precmds = self.config["general"].get("modules_prefix")
-        if not precmds is None:
-            self.precmds = precmds
+        prefcmd = self.config["general"].get("methods_prefix")
+        if not prefcmd is None:
+            Commands.prefcmd = prefcmd
+        self.prefcmds = "cmds_"
+        prefcmds = self.config["general"].get("modules_prefix")
+        if not prefcmds is None:
+            self.prefcmds = prefcmds
         self.log = log
         self.lock = Lock()
+        self.stop_event = stop_event
         self._load_commands()
         self._set_cmods()
 
@@ -224,7 +268,7 @@ class CommandsLoader:
         with os.scandir(self.modpath) as it:
             for entry in it:
                 if (
-                    entry.name.startswith(self.precmds)
+                    entry.name.startswith(self.prefcmds)
                     and entry.name.endswith(".py")
                     and entry.is_file()
                 ):
@@ -232,7 +276,7 @@ class CommandsLoader:
                     if not obj is None:
                         nmod = obj.nickname
                         if nmod is None:
-                            nmod = (entry.name[:-3])[len(self.precmds):]
+                            nmod = (entry.name[:-3])[len(self.prefcmds):]
                         cmds.update({nmod: obj})
                         self.log.info('module "{}" loaded'.format(nmod))
                     else:
@@ -251,15 +295,20 @@ class CommandsLoader:
 
         members = inspect.getmembers(module, inspect.isclass)
         conf = None
-        if name[len(self.precmds):] in self.config.sections():
-            conf = self.config[name[len(self.precmds):]]
+        if name[len(self.prefcmds):] in self.config.sections():
+            conf = self.config[name[len(self.prefcmds):]]
 
         obj = None
         for n, c in members:
             if issubclass(c, Commands) and (n != "Commands"):
+                try:
                     obj = c(conf, self.log)
+                except:
+                    self.log.error(f"The object '{c.__name__}' could not be instantiated.")
+                    continue
                 obj.log = self.log
                 obj.lock = self.lock
+                obj.stop_all_event = self.stop_event
                 break
 
         return obj
@@ -271,9 +320,15 @@ class CommandsLoader:
     def _load_dependencies(self):
         for k, v in self.cmods.items():
             if hasattr(v, "dependencies"):
-                for p in v.dependencies:
-                    if p in self.cmods.keys():
-                        setattr(v, p, self.cmods[p])
+                deps = v.dependencies
+                # dependencies can be a list or dictionary
+                if isinstance(v.dependencies, list):
+                    deps = {}
+                    for d in v.dependencies:
+                        deps[d] = d
+                for p, pv in deps.items():
+                    if pv in self.cmods.keys():
+                        setattr(v, p, self.cmods[pv])
                     else:
                         self.log.error(
                             'Dependency "{}" of module "{}" could not be satisfied'.format(
@@ -287,11 +342,20 @@ class CommandsLoader:
             if v.threaded:
                 v.start()
 
+    def stop(self):
+        for k, v in self.cmods.items():
+            if v.threaded:
+                v.stop()
+
     def join(self):
         for k, v in self.cmods.items():
             if v.threaded:
                 v.join()
 
+    def free(self):
+        for k, v in self.cmods.items():
+            v.free()
+
 
 class AppEngine:
     def __init__(
@@ -301,16 +365,25 @@ class AppEngine:
         log_file: str = "",
         debug: bool = False,
     ) -> None:
+        self.cl = None
         self.app_name = app_name
         self.conf = ConfigParser()
         if conf_file != "":
             self.parse_config(conf_file)
         self.def_log(log_file)
-
+        signal.signal(signal.SIGINT, self.signal_handler)
         if debug:
             self.log.setLevel(logging.DEBUG)
         else:
             self.log.setLevel(logging.WARNING)
+        # Mechanism to stop the application
+        self.stop_event = Event()
+        self.stop_thread = Thread(target=self.wait_stop, args=(self.stop_event,))
+        self.stop_thread.start()
+
+    def signal_handler(self, sig, frame):
+        print("\nExiting.")
+        self.stop()
 
     def parse_config(self, cf: str):
         if os.path.exists(cf) and os.path.isfile(cf):
@@ -333,13 +406,17 @@ class AppEngine:
             if is_writeable:
                 self.log.addHandler(logging.FileHandler(fname))
             else:
-                self.log.addHandler(journal.JournalHandler())
                 self.log.error('No write permissions: "{}"'.format(fname))
 
-        else:
-            self.log.addHandler(journal.JournalHandler())
-
     def exec(self, modpath: str = ""):
-        cl = CommandsLoader(self.conf, self.log, modpath)
-        cl.start()
-        cl.join()
+        self.cl = CommandsLoader(self.stop_event, self.conf, self.log, modpath)
+        self.cl.start()
+        self.cl.join()
+        self.cl.free()
+
+    def wait_stop(self, evnt):
+        evnt.wait()
+        self.cl.stop()
+
+    def stop(self):
+        self.stop_event.set()