[modules] Add module to measure the RTT of an address

The module simply calls the external tool "ping" to retriev RTT
information and displays the average RTT in the widget.

Addresses issue #6

bumblebee/modules/ping.py

@@ -0,0 +1,98 @@
+from __future__ import absolute_import
+
+import re
+import time
+import shlex
+import threading
+import subprocess
+
+import bumblebee.module
+import bumblebee.util
+
+def description():
+    return "Periodically checks the RTT of a configurable IP"
+
+def parameters():
+    return [
+        "ping.interval: Time in seconds between two RTT checks (defaults to 60)",
+        "ping.address: IP address to check",
+        "ping.warning: Threshold for warning state, in seconds (defaults to 1.0)",
+        "ping.critical: Threshold for critical state, in seconds (defaults to 2.0)",
+        "ping.timeout: Timeout for waiting for a reply (defaults to 5.0)",
+        "ping.probes: Number of probes to send (defaults to 5)",
+    ]
+
+def get_rtt(obj):
+    loops = obj.get("interval")
+
+    for thread in threading.enumerate():
+        if thread.name == "MainThread":
+            main = thread
+
+    interval = obj.get("interval")
+    while main.is_alive():
+        loops += 1
+        if loops < interval:
+            time.sleep(1)
+            continue
+
+        loops = 0
+        try:
+            res = subprocess.check_output(shlex.split("ping -n -q -c {} -W {} {}".format(
+                obj.get("rtt-probes"), obj.get("rtt-timeout"), obj.get("address")
+            )))
+        except Exception as e:
+            obj.set("rtt-unreachable", True)
+            break
+
+        obj.set("rtt-unreachable", False)
+
+        for line in res.decode().split("\n"):
+            if not line.startswith("rtt"): continue
+            m = re.search(r'([0-9\.]+)/([0-9\.]+)/([0-9\.]+)/([0-9\.]+)\s+(\S+)', line)
+
+            obj.set("rtt-min", float(m.group(1)))
+            obj.set("rtt-avg", float(m.group(2)))
+            obj.set("rtt-max", float(m.group(3)))
+            obj.set("rtt-unit", m.group(5))
+
+class Module(bumblebee.module.Module):
+    def __init__(self, output, config, alias):
+        super(Module, self).__init__(output, config, alias)
+
+        self._counter = {}
+
+        self.set("address", self._config.parameter("address", "8.8.8.8"))
+        self.set("interval", self._config.parameter("interval", 60))
+        self.set("rtt-probes", self._config.parameter("probes", 5))
+        self.set("rtt-timeout", self._config.parameter("timeout", 5.0))
+
+        self._thread = threading.Thread(target=get_rtt, args=(self,))
+        self._thread.start()
+
+    def set(self, what, value):
+        self._counter[what] = value
+
+    def get(self, what):
+        return self._counter.get(what, 0)
+
+    def widgets(self):
+        text = "{}: {:.1f}{}".format(
+            self.get("address"),
+            self.get("rtt-avg"),
+            self.get("rtt-unit")
+        )
+
+        if self.get("rtt-unreachable"):
+            text = "{}: unreachable".format(self.get("address"))
+
+        return bumblebee.output.Widget(self, text)
+
+    def warning(self, widget):
+        return self.get("rtt-avg") > float(self._config.parameter("warning", 1.0))*1000.0
+
+    def critical(self, widget):
+        if self.get("rtt-unreachable"): return True
+        return self.get("rtt-avg") > float(self._config.parameter("critical", 2.0))*1000.0
+
+# vim: tabstop=8 expandtab shiftwidth=4 softtabstop=4