monitor_app.py

import os
import time


def get_memory(key="total"):
    key_to_index = {
        "total": 1,
        "used": 2,
        "free": 3,
        "shared": 4,
        "buff/cache": 5,
        "available": 6,
    }
    if key.startswith("swap"):
        totalMemory = os.popen("free -m").readlines()[2].split()[key_to_index[key[4:]]]
    else:
        totalMemory = os.popen("free -m").readlines()[1].split()[key_to_index[key]]

    return int(totalMemory)


def get_pids(appname):
    pids = os.popen("pidof {}".format(appname)).readlines()
    if len(pids) == 0:
        return None
    pids = pids[0].split()
    return pids


def get_process_memory(pids, key="resident"):
    if pids is None:
        return 0
    # See https://askubuntu.com/a/392274/859660
    key_to_index = {
        "size": 0,
        "resident": 1,
        "share": 2,
        "trs": 3,
        "drs": 4,
        "lrs": 5,
        "dt": 6,
    }
    total = 0
    for pid in pids:
        lines = os.popen("cat /proc/{}/statm".format(pid)).readlines()
        if len(lines) == 1:
            result = int(lines[0].split()[key_to_index[key]])
            if key in {"size", "resident", "trs", "lrs", "share"}:
                result = result * 4096 // 1024 // 1024 # Mb
            elif key in {"drs", "dt"}:
                pass
        else:
            result = 0
        total += result
    return total


if __name__ == '__main__':
    delay_seconds = 1
    appname = "metashape"

    pids = get_pids(appname)
    if pids is not None:
        for pid in pids:
            print("{} PID={} resident memory: {} Mb".format(appname, pid, get_process_memory([pid])))
    else:
        print("Failed to establish PID for {}".format(appname))

    line_format = "[{: <20}, {: <20}, {: <20}, {: <20}, {: <20}, {: <20}, {: <20}, {: <20}, {: <20}, {: <20}, {: <20}],"
    print(line_format.format("[Time, hh:mm:ss]", "[Total memory, Mb]", "[Used memory, Mb]", "[Free memory, Mb]", "[Shared memory, Mb]", "[Buff/cache, Mb]", "[Avail, Mb]", "[MS size, Mb]", "[MS resident, Mb]", "[MS share, Mb]", "[MS PIDs]", ))
    while True:
        cur_time = time.strftime("%H:%M:%S", time.localtime())
        pids = get_pids(appname)
        print(line_format.format(cur_time, get_memory("total"), get_memory("used"), get_memory("free"), get_memory("shared"), get_memory("buff/cache"), get_memory("available"), get_process_memory(pids, "size"), get_process_memory(pids, "resident"), get_process_memory(pids, "share"), str(pids) if pids is not None else "None"))
        time.sleep(delay_seconds)