netstats2lcd.py

import copy
import time
import Adafruit_CharLCD as LCD

ifstats = {
    "eth0": { "tx": 0, "rx": 0 },
    "eth1": { "tx": 0, "rx": 0 }
}

ifstats_prev = copy.deepcopy(ifstats)

def get_ifstats(line, ifname):
    """if ifname found on this line, insert counters into dict"""
    fields = line.split()
    if fields[0] == (ifname + ":"):
        ifstats[ifname]["rx"] = int(fields[1])
        ifstats[ifname]["tx"] = int(fields[9])

# we only have 8 characters for the number, so display up to 1 Gbps in kbps

def scale_bps(bytesNow, bytesPrev, deltaTimeNS):
    deltaBits = 8 * (bytesNow - bytesPrev)
    bytesPerNS = deltaBits / deltaTimeNS
    kbytesPerSec = 1000000 * bytesPerNS
    return int(kbytesPerSec)

try:
    # Initialize the LCD using the pins
    lcd = LCD.Adafruit_CharLCDBackpack(address=0x21)
    # turn LCD backlight on
    lcd.set_backlight(0)
    lastTime = time.time_ns()

    while True:
        lcd.clear()
        # find the time delta since last reading
        now = time.time_ns()
        deltaTime = now - lastTime
        lastTime = now
        # avoid divide by zero in rate calculation
        if 0 == deltaTime:
            deltaTime = 1
        # parse the current stats (pseudo-file has one line per interface, including lo and wlan0)
        with open("/proc/net/dev", "r") as f:
            for index, line in enumerate(f):
                get_ifstats(line, "eth0")
                get_ifstats(line, "eth1")
        eth0_tx_bps = scale_bps(ifstats["eth0"]["tx"], ifstats_prev["eth0"]["tx"], deltaTime)
        eth0_rx_bps = scale_bps(ifstats["eth0"]["rx"], ifstats_prev["eth0"]["rx"], deltaTime)
        eth1_tx_bps = scale_bps(ifstats["eth1"]["tx"], ifstats_prev["eth1"]["tx"], deltaTime)
        eth1_rx_bps = scale_bps(ifstats["eth1"]["rx"], ifstats_prev["eth1"]["rx"], deltaTime)
        ifstats_prev = copy.deepcopy(ifstats)
        lcdline = "{:>8}{:>8}\n{:>8}{:>8}".format(eth0_rx_bps, eth0_tx_bps, eth1_rx_bps, eth1_tx_bps)
        lcd.message(lcdline)
        print(lcdline + "\n")
        time.sleep(2)
except KeyboardInterrupt:
    pass
finally:
    lcd.set_backlight(1)