Add network traffic module

This module allows to display packets/bytes sent/received per second.
The implementation uses `psutil.net_io_counters`.

i3pystatus/network_traffic.py

@@ -0,0 +1,49 @@
+from . import IntervalModule
+from .core.util import round_dict
+import psutil
+
+class NetworkTraffic(IntervalModule):
+    """
+    Network traffic per interface, i.e., packets/bytes sent/received per second.
+
+    Requires the PyPI packages `psutil`.
+
+    Available formatters:
+
+    * `{interface}` — the configured network interface
+    * `{bytes_sent}` — bytes sent per second (divided by divisor)
+    * `{bytes_recv}` — bytes received per second (divided by divisor)
+    * `{packets_sent}` — bytes sent per second (divided by divisor)
+    * `{packets_recv}` — bytes received per second (divided by divisor)
+    """
+
+    interval = 1
+    settings = (
+        ("format", "format string"),
+        ("interface", "network interface"),
+        ("divisor", "divide all byte values by this value"),
+        ("round_size", "defines number of digits in round"),
+    )
+ 
+    format = "{interface} \u2197{bytes_sent}kB/s \u2198{bytes_recv}kB/s"
+    interface = "eth0"
+    divisor = 1024
+    round_size = None
+ 
+    pnic = None
+    def run(self):
+        pnic_before = self.pnic
+        self.pnic = psutil.net_io_counters(pernic=True)[self.interface]
+        if not pnic_before: return None
+        cdict = {
+            "bytes_sent": (self.pnic.bytes_sent - pnic_before.bytes_sent) / self.divisor,
+            "bytes_recv": (self.pnic.bytes_recv - pnic_before.bytes_recv) / self.divisor,
+            "packets_sent": self.pnic.packets_sent - pnic_before.packets_sent,
+            "packets_recv": self.pnic.packets_recv - pnic_before.packets_recv,
+        }
+        round_dict(cdict, self.round_size)
+        cdict["interface"] = self.interface
+        self.output = {
+            "full_text": self.format.format(**cdict),
+            "instance": self.interface,
+        }