From 5ba255f635a0af422be55678f4061cd9cf09c113 Mon Sep 17 00:00:00 2001
From: Anton Ermak <anton@ermak.us>
Date: Thu, 28 Dec 2017 12:14:34 +0700
Subject: [PATCH] Watchdog for bot process

---
 freqtrade/main.py     |  9 +++++
 freqtrade/misc.py     |  6 ++++
 freqtrade/watchdog.py | 79 +++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 94 insertions(+)
 create mode 100644 freqtrade/watchdog.py

diff --git a/freqtrade/main.py b/freqtrade/main.py
index 5e8680b85..3f929b0a7 100755
--- a/freqtrade/main.py
+++ b/freqtrade/main.py
@@ -19,6 +19,7 @@ from freqtrade.misc import State, get_state, update_state, parse_args, throttle,
     load_config
 from freqtrade.persistence import Trade
 from freqtrade.fiat_convert import CryptoToFiatConverter
+from freqtrade.watchdog import Watchdog
 
 logger = logging.getLogger('freqtrade')
 
@@ -441,6 +442,13 @@ def main(sysargv=sys.argv[1:]) -> None:
         else:
             logger.info('Dry run is disabled. (--dry_run_db ignored)')
 
+    watchdog = Watchdog()
+
+    if args.watchdog_enable:
+        logger.info('Using watchdog to monitor process (--watchdog)')
+        if not watchdog.start():
+            return
+
     try:
         init(_CONF)
         old_state = None
@@ -460,6 +468,7 @@ def main(sysargv=sys.argv[1:]) -> None:
                     nb_assets=args.dynamic_whitelist,
                 )
             old_state = new_state
+            watchdog.heartbeat()
     except KeyboardInterrupt:
         logger.info('Got SIGINT, aborting ...')
     except BaseException:
diff --git a/freqtrade/misc.py b/freqtrade/misc.py
index afc4334e8..f2d4433ae 100644
--- a/freqtrade/misc.py
+++ b/freqtrade/misc.py
@@ -142,6 +142,12 @@ def parse_args(args: List[str], description: str):
         metavar='INT',
         nargs='?',
     )
+    parser.add_argument(
+        '-w', '--watchdog',
+        help='Run under watchdog (restart process if main loop is stalled)',  # noqa
+        action='store_true',
+        dest='watchdog_enable',
+    )
 
     build_subcommands(parser)
     return parser.parse_args(args)
diff --git a/freqtrade/watchdog.py b/freqtrade/watchdog.py
new file mode 100644
index 000000000..b0fde770e
--- /dev/null
+++ b/freqtrade/watchdog.py
@@ -0,0 +1,79 @@
+import os
+import signal
+import time
+import logging
+from multiprocessing import Value
+
+logger = logging.getLogger('freqtrade.watchdog')
+
+WATCHDOG_TIMEOUT = 300
+
+
+class Watchdog:
+
+    shared_heartbeat = Value('d', 0.0)
+    kill_signal = None
+
+    def heartbeat(self) -> None:
+        logger.debug("Heartbeat")
+        self.shared_heartbeat.value = time.time()
+
+    def exit_gracefully(self, signum, frame):
+        logger.warning("Kill signal: {}".format(signum))
+        self.kill_signal = signum
+
+    def kill(self, pid):
+        logger.info("Stopping pid {}".format(pid))
+        os.kill(pid, signal.SIGTERM)  # Better use sigint and then sigterm?
+        os.wait()
+
+    def start(self) -> bool:
+        self.heartbeat()
+        pid = os.fork()
+        if pid != 0:
+            # In watchdog proces, run it
+            if not self.run(pid):
+                # Got exit signal
+                return False
+            else:
+                # Forked new children, continue to main
+                self.heartbeat()
+                return True
+        else:
+            # In children process, continue to main
+            return True
+
+    def run(self, pid) -> bool:
+        logger.info("Watchdog started")
+        self.orig_SIGINT = signal.signal(signal.SIGINT, self.exit_gracefully)
+        self.orig_SIGTERM = signal.signal(signal.SIGTERM, self.exit_gracefully)
+        try:
+            while True:
+                if self.kill_signal:
+                    raise KeyboardInterrupt()
+
+                timeout = time.time() - self.shared_heartbeat.value
+
+                if timeout > WATCHDOG_TIMEOUT:
+                    logger.warning("Kill process due to timeout: {}".format(timeout))
+                    self.kill(pid)
+                    new_pid = os.fork()
+                    if new_pid == 0:
+                        logger.info("New children forked")
+                        signal.signal(signal.SIGINT, self.orig_SIGINT)
+                        signal.signal(signal.SIGTERM, self.orig_SIGTERM)
+                        return True
+                    else:
+                        pid = new_pid
+
+                time.sleep(1)
+
+        except Exception as ex:
+            logger.exception(ex)
+            self.kill(pid)
+            return False
+
+        except KeyboardInterrupt:
+            logger.info("Watchdog stopped")
+            self.kill(pid)
+            return False