[#301] Merged ping backend and plugin.

Also, removed `ping` response types.

platypush/backend/ping/__init__.py

@@ -1,76 +0,0 @@
-import time
-
-from typing import List, Tuple
-
-from platypush.backend import Backend
-from platypush.context import get_plugin
-from platypush.message.event.ping import HostUpEvent, HostDownEvent
-from platypush.utils.workers import Worker, Workers
-
-
-class PingBackend(Backend):
-    """
-    This backend allows you to ping multiple remote hosts at regular intervals.
-    """
-
-    class Pinger(Worker):
-        def __init__(self, *args, **kwargs):
-            self.timeout = kwargs.pop('timeout')
-            self.count = kwargs.pop('count')
-            super().__init__(*args, **kwargs)
-
-        def process(self, host: str) -> Tuple[str, bool]:
-            pinger = get_plugin('ping')
-            response = pinger.ping(host, timeout=self.timeout, count=self.count).output
-            return host, response['success'] is True
-
-    def __init__(
-        self,
-        hosts: List[str],
-        timeout: float = 5.0,
-        interval: float = 60.0,
-        count: int = 1,
-        *args,
-        **kwargs
-    ):
-        """
-        :param hosts: List of IP addresses or host names to monitor.
-        :param timeout: Ping timeout.
-        :param interval: Interval between two scans.
-        :param count: Number of pings per host. A host will be considered down
-            if all the ping requests fail.
-        """
-
-        super().__init__(*args, **kwargs)
-        self.hosts = {h: None for h in hosts}
-        self.timeout = timeout
-        self.interval = interval
-        self.count = count
-
-    def run(self):
-        super().run()
-        self.logger.info(
-            'Starting ping backend with {} hosts to monitor'.format(len(self.hosts))
-        )
-
-        while not self.should_stop():
-            workers = Workers(10, self.Pinger, timeout=self.timeout, count=self.count)
-
-            with workers:
-                for host in self.hosts.keys():
-                    workers.put(host)
-
-            for response in workers.responses:
-                host, is_up = response
-                if is_up != self.hosts[host]:
-                    if is_up:
-                        self.bus.post(HostUpEvent(host))
-                    else:
-                        self.bus.post(HostDownEvent(host))
-
-                self.hosts[host] = is_up
-
-            time.sleep(self.interval)
-
-
-# vim:sw=4:ts=4:et:

platypush/backend/ping/manifest.yaml

@@ -1,14 +0,0 @@
-manifest:
-  events:
-    platypush.message.event.ping.HostDownEvent: if a host stops responding ping requests
-    platypush.message.event.ping.HostUpEvent: if a host starts responding ping requests
-  install:
-    apt:
-      - iputils-ping
-    dnf:
-      - iputils
-    pacman:
-      - iputils
-
-  package: platypush.backend.ping
-  type: backend

platypush/message/event/ping.py

@@ -2,21 +2,22 @@ from platypush.message.event import Event
 
 
 class PingEvent(Event):
-    """ Ping event, used for testing purposes """
+    """Ping event, used for testing purposes"""
 
-    def __init__(self, message=None, *args, **kwargs):
+    def __init__(self, *args, message=None, **kwargs):
         """
         :param message: Ping message
         :type message: object
         """
 
-        super().__init__(message=message, *args, **kwargs)
+        super().__init__(*args, message=message, **kwargs)
 
 
 class HostDownEvent(Event):
     """
     Event triggered when a remote host stops responding ping requests.
     """
+
     def __init__(self, host: str, *args, **kwargs):
         super().__init__(host=host, *args, **kwargs)
 
@@ -25,8 +26,36 @@ class HostUpEvent(Event):
     """
     Event triggered when a remote host starts responding ping requests.
     """
+
     def __init__(self, host: str, *args, **kwargs):
         super().__init__(host=host, *args, **kwargs)
 
 
+class PingResponseEvent(Event):
+    """
+    Event triggered when a ping response is received.
+    """
+
+    def __init__(
+        self,
+        host: str,
+        min: float,
+        max: float,
+        avg: float,
+        mdev: float,
+        *args,
+        **kwargs
+    ):
+        """
+        :param host: Remote host IP or name.
+        :param min: Minimum round-trip time (in ms).
+        :param max: Maximum round-trip time (in ms).
+        :param avg: Average round-trip time (in ms).
+        :param mdev: Standard deviation of the round-trip time (in ms).
+        """
+        super().__init__(
+            host=host, min=min, max=max, avg=avg, mdev=mdev, *args, **kwargs
+        )
+
+
 # vim:sw=4:ts=4:et:

platypush/message/response/ping.py

@@ -1,27 +0,0 @@
-from typing import Optional
-
-from platypush.message.response import Response
-
-
-class PingResponse(Response):
-    # noinspection PyShadowingBuiltins
-    def __init__(self,
-                 host: str,
-                 success: bool,
-                 *args,
-                 min: Optional[float] = None,
-                 max: Optional[float] = None,
-                 avg: Optional[float] = None,
-                 mdev: Optional[float] = None,
-                 **kwargs):
-        super().__init__(*args, output={
-            'host': host,
-            'success': success,
-            'min': min,
-            'max': max,
-            'avg': avg,
-            'mdev': mdev,
-        }, **kwargs)
-
-
-# vim:sw=4:ts=4:et:

platypush/plugins/ping/__init__.py

@@ -1,43 +1,113 @@
+import logging
 import re
 import subprocess
 import sys
+from concurrent.futures import ProcessPoolExecutor
+from typing import Dict, Optional, List
 
-from typing import Optional, List
-
-from platypush.message.response.ping import PingResponse
-from platypush.plugins import Plugin, action
+from platypush.message.event.ping import HostUpEvent, HostDownEvent, PingResponseEvent
+from platypush.plugins import RunnablePlugin, action
+from platypush.schemas.ping import PingResponseSchema
 
 PING_MATCHER = re.compile(
     r"(?P<min>\d+.\d+)/(?P<avg>\d+.\d+)/(?P<max>\d+.\d+)/(?P<mdev>\d+.\d+)"
 )
 
-PING_MATCHER_BUSYBOX = re.compile(
-    r"(?P<min>\d+.\d+)/(?P<avg>\d+.\d+)/(?P<max>\d+.\d+)"
-)
+PING_MATCHER_BUSYBOX = re.compile(r"(?P<min>\d+.\d+)/(?P<avg>\d+.\d+)/(?P<max>\d+.\d+)")
 
 WIN32_PING_MATCHER = re.compile(r"(?P<min>\d+)ms.+(?P<max>\d+)ms.+(?P<avg>\d+)ms")
 
 
-class PingPlugin(Plugin):
+def ping(host: str, ping_cmd: List[str], logger: logging.Logger) -> dict:
+    err_response = dict(
+        PingResponseSchema().dump(
+            {
+                "host": host,
+                "success": False,
+            }
+        )
+    )
+
+    with subprocess.Popen(
+        ping_cmd,
+        stdout=subprocess.PIPE,
+        stderr=subprocess.PIPE,
+    ) as pinger:
+        try:
+            out = pinger.communicate()
+            if sys.platform == "win32":
+                match = WIN32_PING_MATCHER.search(str(out).rsplit("\n", maxsplit=1)[-1])
+                min_val, avg_val, max_val = match.groups()
+                mdev_val = None
+            elif "max/" not in str(out):
+                match = PING_MATCHER_BUSYBOX.search(
+                    str(out).rsplit("\n", maxsplit=1)[-1]
+                )
+                assert match is not None, f"No match found in {out}"
+                min_val, avg_val, max_val = match.groups()
+                mdev_val = None
+            else:
+                match = PING_MATCHER.search(str(out).rsplit("\n", maxsplit=1)[-1])
+                assert match is not None, f"No match found in {out}"
+                min_val, avg_val, max_val, mdev_val = match.groups()
+
+            return dict(
+                PingResponseSchema().dump(
+                    {
+                        "host": host,
+                        "success": True,
+                        "min": float(min_val),
+                        "max": float(max_val),
+                        "avg": float(avg_val),
+                        "mdev": float(mdev_val) if mdev_val is not None else None,
+                    }
+                )
+            )
+        except Exception as e:
+            if not isinstance(e, (subprocess.CalledProcessError, KeyboardInterrupt)):
+                logger.warning("Error while pinging host %s: %s", host, e)
+                logger.exception(e)
+
+            pinger.kill()
+            pinger.wait()
+            return err_response
+
+
+class PingPlugin(RunnablePlugin):
     """
-    Perform ICMP network ping on remote hosts.
+    This integration allows you to:
+
+        1. Programmatic ping a remote host.
+        2. Monitor the status of a remote host.
+
     """
 
-    def __init__(self, executable: str = 'ping', count: int = 1, timeout: float = 5.0, **kwargs):
+    def __init__(
+        self,
+        executable: str = 'ping',
+        count: int = 1,
+        timeout: float = 5.0,
+        hosts: Optional[List[str]] = None,
+        poll_interval: float = 10.0,
+        **kwargs,
+    ):
         """
         :param executable: Path to the ``ping`` executable. Default: the first ``ping`` executable found in PATH.
         :param count: Default number of packets that should be sent (default: 1).
         :param timeout: Default timeout before failing a ping request (default: 5 seconds).
+        :param hosts: List of hosts to monitor. If not specified then no hosts will be monitored.
+        :param poll_interval: How often the hosts should be monitored (default: 10 seconds).
         """
 
-        super().__init__(**kwargs)
+        super().__init__(poll_interval=poll_interval, **kwargs)
         self.executable = executable
         self.count = count
         self.timeout = timeout
+        self.hosts: Dict[str, Optional[bool]] = {h: None for h in (hosts or [])}
 
     def _get_ping_cmd(self, host: str, count: int, timeout: float) -> List[str]:
         if sys.platform == 'win32':
-            return [
+            return [  # noqa
                 self.executable,
                 '-n',
                 str(count or self.count),
@@ -58,38 +128,78 @@ class PingPlugin(Plugin):
         ]
 
     @action
-    def ping(self, host: str, count: Optional[int] = None, timeout: Optional[float] = None) -> PingResponse:
+    def ping(
+        self, host: str, count: Optional[int] = None, timeout: Optional[float] = None
+    ) -> dict:
         """
         Ping a remote host.
         :param host: Remote host IP or name
-        :param count: Number of packets that should be sent (default: 1).
-        :param timeout: Timeout before failing a ping request (default: 5 seconds).
+        :param count: Overrides the configured number of packets that should be
+            sent (default: 1).
+        :param timeout: Overrides the configured timeout before failing a ping
+            request (default: 5 seconds).
+        :return: .. schema:: ping.PingResponseSchema
         """
+        return self._ping(host=host, count=count, timeout=timeout)
 
-        count = count or self.count
-        timeout = timeout or self.timeout
+    def _ping(
+        self, host: str, count: Optional[int] = None, timeout: Optional[float] = None
+    ) -> dict:
+        return ping(
+            host=host,
+            ping_cmd=self._get_ping_cmd(
+                host=host, count=count or self.count, timeout=timeout or self.timeout
+            ),
+            logger=self.logger,
+        )
 
-        pinger = subprocess.Popen(
-            self._get_ping_cmd(host, count=count, timeout=timeout),
-            stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+    def _process_ping_result(self, result: dict):
+        host = result.get("host")
+        if host is None:
+            return
 
-        try:
-            out = pinger.communicate()
-            if sys.platform == "win32":
-                match = WIN32_PING_MATCHER.search(str(out).split("\n")[-1])
-                min_val, avg_val, max_val = match.groups()
-                mdev_val = None
-            elif "max/" not in str(out):
-                match = PING_MATCHER_BUSYBOX.search(str(out).split("\n")[-1])
-                min_val, avg_val, max_val = match.groups()
-                mdev_val = None
-            else:
-                match = PING_MATCHER.search(str(out).split("\n")[-1])
-                min_val, avg_val, max_val, mdev_val = match.groups()
+        success = result.get("success")
+        if success is None:
+            return
 
-            return PingResponse(host=host, success=True, min=min_val, max=max_val, avg=avg_val, mdev=mdev_val)
-        except (subprocess.CalledProcessError, AttributeError):
-            return PingResponse(host=host, success=False)
+        if success:
+            if self.hosts.get(host) in (False, None):
+                self._bus.post(HostUpEvent(host=host))
+
+            result.pop("success", None)
+            self._bus.post(PingResponseEvent(**result))
+            self.hosts[host] = True
+        else:
+            if self.hosts.get(host) in (True, None):
+                self._bus.post(HostDownEvent(host=host))
+            self.hosts[host] = False
+
+    def main(self):
+        # Don't start the thread if no monitored hosts are configured
+        if not self.hosts:
+            self.wait_stop()
+            return
+
+        while not self.should_stop():
+            try:
+                with ProcessPoolExecutor() as executor:
+                    for result in executor.map(
+                        ping,
+                        self.hosts.keys(),
+                        [
+                            self._get_ping_cmd(h, self.count, self.timeout)
+                            for h in self.hosts.keys()
+                        ],
+                        [self.logger] * len(self.hosts),
+                    ):
+                        self._process_ping_result(result)
+            except KeyboardInterrupt:
+                break
+            except Exception as e:
+                self.logger.warning("Error while pinging hosts: %s", e)
+                self.logger.exception(e)
+            finally:
+                self.wait_stop(self.poll_interval)
 
 
 # vim:sw=4:ts=4:et:

platypush/plugins/ping/manifest.yaml

@@ -1,5 +1,8 @@
 manifest:
-  events: {}
+  events:
+    - platypush.message.event.ping.HostDownEvent
+    - platypush.message.event.ping.HostUpEvent
+    - platypush.message.event.ping.PingResponseEvent
   install:
     apt:
       - iputils-ping
@@ -7,6 +10,5 @@ manifest:
       - iputils
     pacman:
       - iputils
-
   package: platypush.plugins.ping
   type: plugin

platypush/schemas/ping.py

@@ -0,0 +1,56 @@
+from marshmallow import fields
+from marshmallow.schema import Schema
+
+
+class PingResponseSchema(Schema):
+    """
+    Ping response schema.
+    """
+
+    host = fields.String(
+        required=True,
+        metadata={
+            "description": "Remote host IP or name",
+            "example": "platypush.tech",
+        },
+    )
+
+    success = fields.Boolean(
+        required=True,
+        metadata={
+            "description": "True if the ping was successful, False otherwise",
+            "example": True,
+        },
+    )
+
+    min = fields.Float(
+        required=False,
+        metadata={
+            "description": "Minimum round-trip time (in ms)",
+            "example": 0.1,
+        },
+    )
+
+    max = fields.Float(
+        required=False,
+        metadata={
+            "description": "Maximum round-trip time (in ms)",
+            "example": 0.2,
+        },
+    )
+
+    avg = fields.Float(
+        required=False,
+        metadata={
+            "description": "Average round-trip time (in ms)",
+            "example": 0.15,
+        },
+    )
+
+    mdev = fields.Float(
+        required=False,
+        metadata={
+            "description": "Standard deviation of the round-trip time (in ms)",
+            "example": 0.05,
+        },
+    )