How do I count the messages of Postfix's mailq?

Question

I'm writing a full body detection script with automatic img safe when body is detected via webcam (logitech c170) using a RaspberryPi3, Opencv3 and Python3.5

This is what I have so far

import numpy as np
import cv2
import os


def inside(r, q):
    rx, ry, rw, rh = r
    qx, qy, qw, qh = q
    return rx > qx and ry > qy and rx + rw < qx + qw and ry + rh < qy + qh


def draw_detections(img, rects, thickness = 1):
    for x, y, w, h in rects:

        pad_w, pad_h = int(0.15*w), int(0.05*h)
        cv2.rectangle(img, (x+pad_w, y+pad_h), (x+w-pad_w, y+h-pad_h), (0, 255, 0), thickness)


if __name__ == '__main__':

    num = 0
    hog = cv2.HOGDescriptor()
    hog.setSVMDetector( cv2.HOGDescriptor_getDefaultPeopleDetector() )
    cap=cv2.VideoCapture(0)
    previously_found = False

    while True:
        _,frame=cap.read()
        found,w=hog.detectMultiScale(frame, winStride=(8,8), padding=(32,32), scale=1.05)
        if all(found) and not previously_found:
            previously_found = True
            cv2.imwrite('/home/pi/jebenter/'+'opencv'+str(num)+'.jpg',frame)
            num = num+1
        elif not all(found):
            previously_found = False

        draw_detections(frame,found)
        cv2.imshow('feed',frame)
        ch = 0xFF & cv2.waitKey(1)
        if ch == 27:
            break

    cv2.destroyAllWindows()

When executed I get the following error:

Traceback (most recent call last):
  File "peopledetectF.py, line 30, in <module>
    if all(found) and not previously_found:
ValueError: The truth value of an array with more than one element is ambiguous. Use a.any() or a.all()  

I tried replacing the all with any, didn't work. I read something about using & and * instead of and or

But do not really know how to apply this. Does someone know how to fix this?

Solution 1

I use this:

mailq | grep -c "^[A-F0-9]"

You can pipe the output of mailq through various other filters such as uniq, sort and wc to get other statistics.

Solution 2

either mailq | tail -n 1 or find /var/spool/postfix/deferred -type f | wc -l

both works

Comments

[andy]

This is not accurate. When the Postfix queue is empty, then run 'mailq', we will get "Mail queue is empty" which also match "^[0-9A-Z]". And in such a situation it is not accurate.

[Ladadadada]

A better regex is ^[A-F0-9] which correctly results in 0 when the mail queue is empty. I've edited the answer.

[Geoffrey]

How silly, the last line of the output is the count

[rob]

I get "682430 Kbytes in 26472 Requests." for the first one and "23" for the second one.

[Marije Miedema]

Tried but I get the following error: Traceback (most recent call last): File "peopledetectF.py", line 30, in <module> if found.all() and not previously_found: AttributeError: 'tuple' object has no attribute 'all'

[Mike Müller]

Check the content of found. It is a tuple that contains a NumPy array. So maybe found[0].all() works.

[Marije Miedema]

Tried but I'm now getting this. I just started working with python a week ago, I'm sorry if I'm stating obvious problems but I'm a bit lost (and on a deadline..) Traceback (most recent call last): File "peopledetectF.py", line 30, in <module> if found[0].all() and not previously_found: IndexError: tuple index out of range

[Mike Müller]

Does not make sense to me. Either the tuple is empty, than there is no such error message abou tall, or it contains a NumPy array, than it should be index-able.

[Shawn Mathew]

Awesome. Hopefully you made your deadline

[royarisse]

The second one only shows deferred messages, adding the active queue the counts should match up: find /var/spool/postfix/active /var/spool/postfix/deferred -type f | wc -l.