Even in 2020, I am still alive while worrying about memory

On an 8GB laptop, VSCode + some build + 20 tabs open in Chrome ** will run out of memory in a blink of an eye **. It is a very strict user experience such as stall for each OS.

When I think about it, since I was a child, I was often reprimanded by my mother for leaving things out. Rather than just a lack of memory capacity, it may be due to the difficult-to-heal childhood.

I feel that it would be better to get angry with my mother each time than to correct my behavior. So, create a ** mother-like app ** that warns you to close unnecessary software on your desktop when memory is tight.

Environment / Language

--Ubuntu18.04 + gnome3 environment

python3 -* It is possible to connect commands with a pipe, but since python3 is already running on the ubuntu system, there is a negative reason why python3 is okay.

Get the available memory capacity

To get the amount of memory available on Linux, you generally use the ** free command **.

$ free
              total        used        free      shared  buff/cache   available
Mem:        8124668     4831144      267628      201468     3025896     2774924
Swap:       2097148         512     2096636

Of these, the available real memory capacity is ** the available column in the Mem row **. Roughly speaking, this value is calculated by ** [free space + capacity that can be released immediately such as used cache] **.

The content of this free command is a formatted version of the content of the / proc / meminfo pseudo file. Files are easier to handle to use from python, so pick up information from ** / proc / meminfo **.

~$ cat /proc/meminfo 
MemTotal:        8124668 kB
MemFree:          328384 kB
MemAvailable:    2640012 kB
Buffers:          740992 kB
・ ・ ・(Abbreviation)

Try opening the file on the interactive shell. Use the split () function to separate line breaks and spaces, and check the order in which Available comes.

>>> f = open('/proc/meminfo')
>>> f.read().split()
['MemTotal:', '8124668', 'kB', 'MemFree:', '318860', 'kB', 'MemAvailable:', '2631456', 'kB', ...]
>>> f.seek(0)
0
>>> f.read().split()[7]
'2625528'

** A notification should be given when an element with an index of 7 falls below 0.5GB (500,000kB). ** ** (The basis for 0.5GB is somehow)

By the way, as you can see from the above example, the contents are updated ** every time you read ** even after opening.

Skip notifications to the desktop

Use the notify-send command. The format is as follows.

$ notify-send -u critical --icon=Icon name"title" "message"

--Specify the notification type in -u. I'm angry at the content, so I think it's okay to be critical. --You can specify the icon with --icon. You can also specify a custom icon. See below. --You can use simple markup in your messages.

Make an icon

I borrowed a mother icon from Mr. Irasutoya and used it (I also considered a live-action mother, but it was powerful and I felt the emotional resentment).

Place the completed icon as ** shikaruhaha.png ** under ** / usr / share / pixmap . (If you place it in a place other than / usr / share / pixmap, you must specify the path). - Omit the extension when specifying with icon. ** **

$ notify-send -u critical --icon=shikaruhaha "Mother's voice" "<b>J( 'д')Takashi! You're not leaving it messy!</b>"

When you execute the above, it becomes like this.

code

`memwarn.py`


#!/usr/bin/python3
import time
import subprocess

with open("/proc/meminfo") as f:
    while(True):
        f.seek(0)
        arr = f.read().split()
        available = int(arr[7])
        if available < 500000:
            subprocess.call(['notify-send', "-u", "critical", "--icon=shikaruhaha", "Mother's voice", "<b>J( 'д')Takashi! You're not leaving it messy!</b>"])
        time.sleep(2)

--Loop every 2 seconds --Forcibly return the read position with f.seek (0) (because once read, the read position will be at the end) --Use ** subprocess.call ** to execute the shell. Pass shell commands in a space-separated list of strings. -Give execute permission with the file name ** memwarn.py ** and place it under ** / usr / libexec / **.

Deploy

Start after logging in in the X environment. Place the following files under / etc / xdg / autostart /. After logging in, it will start automatically.

`/etc/xdg/autostart/memwarn.desktop`


[Desktop Entry]
Name=MemoryMother
Type=Application
Exec=/usr/libexec/memwarn.py
OnlyShowIn=GNOME;
NoDisplay=true

That's it

Summary

--Don't tell me to add more memory ――No matter how much you are too dependent -** Actually, it's not the name "Takashi" **

reference

https://ota42y.com/blog/2015/09/09/free-command/
http://www.nowhere.co.jp/blog/archives/20171004-065710.html
https://wiki.archlinux.jp/index.php/%E3%83%87%E3%82%B9%E3%82%AF%E3%83%88%E3%83%83%E3%83%97%E3%82%A8%E3%83%B3%E3%83%88%E3%83%AA

[PYTHON] I want to get angry with my mom when my memory is tight