Service and Periodic execution of ping

agent/__main__.py

@@ -1,6 +1,6 @@
 import argparse
 from . import run, get_device_id, get_open_ports, say_hello,\
-    get_claim_token, get_claim_url
+    get_claim_token, get_claim_url, executor
 
 
 def main():
@@ -9,7 +9,8 @@ def main():
         'portscan': (get_open_ports, "Print open ports."),
         'test-cert': (say_hello, "Validate device certificate."),
         'claim-token': (get_claim_token, "Print claim token."),
-        'claim-url': (get_claim_url, "Print claim URL.")
+        'claim-url': (get_claim_url, "Print claim URL."),
+        'daemon': (run_daemon, "Run as daemon")
     }
     help_string = "One of the following:\n\n" + "\n".join(
         ["{: <12} {: <}".format(k, v[1]) for k, v in actions.items()])
@@ -37,12 +38,26 @@ def main():
         action="store_true",
         help="Developer mode: work with locally running server.")
     args = parser.parse_args()
+
     if not args.action:
         run(ping=True, debug=args.debug, dev=args.dev)
+    elif args.action == 'daemon':
+        run_daemon(debug=args.debug, dev=args.dev)
     else:
         run(ping=False, debug=args.debug, dev=args.dev)
         print(actions[args.action][0]())
 
 
+PING_INTERVAL = 60 * 60
+PING_TIMEOUT = 10 * 60
+
+
+def run_daemon(debug, dev):
+    exe = executor.Executor(PING_INTERVAL, run, (True, debug, dev),
+                            timeout=PING_TIMEOUT, debug=debug)
+    executor.schedule(exe)
+    executor.spin()
+
+
 if __name__ == '__main__':
     main()

agent/executor.py

@@ -0,0 +1,129 @@
+import asyncio
+import os
+from concurrent.futures import ThreadPoolExecutor
+from multiprocessing import Process
+from multiprocessing import Queue
+from typing import Callable
+from typing import Dict
+from typing import Any
+
+
+class Executor():
+    MAX_WORKERS = 10
+    processes = MAX_WORKERS or os.cpu_count()
+    executor = ThreadPoolExecutor(max_workers=processes)
+
+    def __init__(self,
+                 interval,
+                 func, fargs,
+                 timeout=None,
+                 callback_timeout=None,
+                 daemon=False,
+                 debug=False):
+        """
+        Periodic process executor. Calls func and sleeps for interval,
+        repeatedly. Kills the process after a timeout.
+        Call schedule() to put it into asyncio loop.
+        :param interval: sleep interval between calls, in seconds. If None, Executor will only execute once.
+        :param func: the function to call
+        :param fargs: function args (tuple) or a single arg
+        :param timeout: kill the process after this many seconds
+        :param callback_timeout: will be called if the process gets killed on timeout
+        :param daemon:
+        """
+        self.interval = interval
+        self.params = {'func': func, 'fn_args': fargs, "p_kwargs": {},
+                       'timeout': timeout, 'callback_timeout': callback_timeout,
+                       'daemon': daemon}
+        self.process = None
+        self.oneshot = interval is None
+        self.should_stop = False
+        self.debug = debug
+
+    async def start(self):
+        """ start calling the process periodically """
+        while not self.should_stop:
+            self.executor.submit(self._submit_unpack_kwargs, self.params)
+            if self.oneshot:
+                break
+            await asyncio.sleep(self.interval)
+
+    def stop(self):
+        """ terminate running process """
+        self.should_stop = True
+        if self.process:
+            self.process.terminate()
+
+    def _submit_unpack_kwargs(self, params):
+        """ unpack the kwargs and call submit """
+        return self._submit(**params)
+
+    def _submit(self,
+                func: Callable,
+                fn_args: Any,
+                p_kwargs: Dict,
+                timeout: float,
+                callback_timeout: Callable[[Any], Any],
+                daemon: bool):
+        """
+        Submits a callable to be executed with the given arguments.
+        Schedules the callable to be executed as func(*args, **kwargs) in a new
+         process.
+        :param func: the function to execute
+        :param fn_args: the arguments to pass to the function. Can be one argument
+                or a tuple of multiple args.
+        :param p_kwargs: the kwargs to pass to the function
+        :param timeout: after this time, the process executing the function
+                will be killed if it did not finish
+        :param callback_timeout: this function will be called with the same
+                arguments, if the task times out.
+        :param daemon: run the child process as daemon
+        :return: the result of the function, or None if the process failed or
+                timed out
+        """
+        p_args = fn_args if isinstance(fn_args, tuple) else (fn_args,)
+        queue = Queue()
+        if self.debug:
+            print("Executor: starting {} {}".format(func.__name__, p_args))
+        p = Process(target=self._process_run,
+                    args=(queue, func, *p_args,), kwargs=p_kwargs)
+
+        if daemon:
+            p.daemon = True
+        self.process = p
+
+        p.start()
+        p.join(timeout=timeout)
+        if not queue.empty():
+            return queue.get()
+        if callback_timeout:
+            callback_timeout(*p_args, **p_kwargs)
+        if p.is_alive():
+            if self.debug:
+                print('Executor: terminating by timeout')
+            p.terminate()
+            p.join()
+
+    @staticmethod
+    def _process_run(queue: Queue, func: Callable[[Any], Any] = None,
+                     *args, **kwargs):
+        """
+        Executes the specified function as func(*args, **kwargs).
+        The result will be stored in the shared dictionary
+        :param func: the function to execute
+        :param queue: a Queue
+        """
+        queue.put(func(*args, **kwargs))
+
+
+def schedule(executor: Executor) -> asyncio.Future:
+    """
+    Put executor into asyncio loop.
+    :param executor:
+    :return: executor.start() wrapped in Future
+    """
+    return asyncio.ensure_future(executor.start())
+
+
+def spin():
+    asyncio.get_event_loop().run_forever()

debian/changelog

@@ -1,3 +1,9 @@
+wott-agent (0.1.5.0) stable; urgency=medium
+
+  * Homegrown periodic process runner.
+
+ -- Artem Martynovich <artem.martynovich@gmail.com>  Mon, 20 May 2019 19:22:32 +0000
+
 wott-agent (0.1.4.9) stable; urgency=medium
 
   * Merges in multiple PRs.

debian/install

@@ -1,2 +1 @@
-debian/wott-agent.timer lib/systemd/system
 misc/pass_hashes.txt opt/wott

debian/wott-agent.service

@@ -1,6 +1,16 @@
 [Unit]
 Description=WoTT Agent
+Wants=network-online.target
+After=network-online.target
+StartLimitIntervalSec=200
+StartLimitBurst=5
 
 [Service]
 Type=simple
-ExecStart=/usr/bin/wott-agent
+ExecStart=/usr/bin/wott-agent daemon
+Restart=always
+RestartSec=1
+
+[Install]
+Alias=wott-agent
+WantedBy=multi-user.target

setup.py

@@ -3,7 +3,7 @@
 
 setup(
     name="wott-agent",
-    version='0.1.4',
+    version='0.1.5',
 
     author="Viktor Petersson",
     author_email="v@viktopia.io",