SPMI

Simple Process Management Interface

Important

This project may be buggy because I haven't tested it much.

TODO

• Document code more accurate
• Develop SLURM backend
• Create PyPI package

What is SPMI

SPMI (Simple Process Management Interface) is a Python package which provides an application and library to start and manage processes via different process managers (now GNU Screen is supported and I am going to add SLURM support).

Important

Only UNIX-like systems are supported.

Installation

Clone git repository

$ git clone https://github.com/LeonidPilyugin/spmi
$ cd spmi

Switch to version

$ git checkout v0.0.1

Install dependencies

$ pip install -r requirements.txt

Add spmi/src to $PYTHONPATH variable and create link to spmi/src/app.py

$ ln -s $PWD/src/spmi/app.py ~/.local/bin/spmi

Basic usage

To start a new process, you need to create a descriptor file. SPMI supports 3 types of descriptor files: JSON, TOML and YAML. There are some examples for each format in examples folder.

Descritor cal.toml:

[task]
id = "cal"
comment = "Prints calendar to stdout."

[task.backend]
type = "screen"

[task.wrapper]
type = "default"
command = "cal"
mixed_stdout = true

View documentation to learn about descriptor structure.

Before starting a new process, ensure that GNU Screen is installed

$ screen -v
Screen version 4.09.01 (GNU) 20-Aug-23

Load descriptor to SPMI

$ spmi load cal.toml
[2024-07-13 18:21:00,240 - Spmi - INFO]
Loaded 1 manageable

View list of tasks

$ spmi list
[2024-07-13 18:21:55,432 - Spmi - INFO]
Registered 1 manageable
ID        ACTIVE    COMMENT
cal       inactive  Prints calendar to stdout.

Start cal task

$ spmi start cal
[2024-07-13 18:24:48,337 - Spmi - INFO]
Starting manageable "cal"
[2024-07-13 18:24:48,344 - Spmi - INFO]
Started 1 manageables

And view its status

$ spmi status cal
cal (task) - Prints calendar to stdout.
      Active: inactive since 2024-07-13 18:24:49 (0:01:03 ago)
        Path: "/home/leonid/.spmi/cal"
Backend type: screen
  Backend ID: 74870
Wrapper type: default
     Command: cal
         PID: 74915
   Exit code: 0

 7  8  9 10 11 12 13
14 15 16 17 18 19 20
21 22 23 24 25 26 27
28 29 30 31


[2024-07-13 18:25:52,255 - Spmi - INFO]
Showed 1 manageables

Next, load ping.toml example

$ spmi load ping.toml
[2024-07-13 18:32:20,105 - Spmi - INFO]
Loaded 1 manageable

And start it

$ spmi start ping
[2024-07-13 18:33:12,546 - Spmi - INFO]
Starting manageable "ping"
[2024-07-13 18:33:12,554 - Spmi - INFO]
Started 1 manageables

If you do instructions fast, you may see that this task is active

$ spmi status ping
ping (task) - Pinges localhost 10 times.
      Active: active since 2024-07-13 18:33:12 (0:00:01 ago)
        Path: "/home/leonid/.spmi/ping"
Backend type: screen
  Backend ID: 75810
Wrapper type: default
     Command: ping -c 10 -i 1 localhost
         PID: 75855

PING localhost (::1) 56 data bytes
64 bytes from localhost (::1): icmp_seq=1 ttl=64 time=0.011 ms
64 bytes from localhost (::1): icmp_seq=2 ttl=64 time=0.034 ms

[2024-07-13 18:33:13,794 - Spmi - INFO]
Showed 1 manageables

If you don't, start echo.toml example

$ spmi load echo.toml
[2024-07-13 18:36:13,794 - Spmi - INFO]
Loaded 1 manageable
$ spmi start echo

And view its status

$ spmi status echo
echo (task) - A forever echo command.
      Active: active since 2024-07-13 18:36:49 (0:00:44 ago)
        Path: "/home/leonid/.spmi/echo"
Backend type: screen
  Backend ID: 76113
Wrapper type: default
     Command: cat -
         PID: 76158



[2024-07-13 18:37:33,406 - Spmi - INFO]
Showed 1 manageables

SPMI allows you to communicate with started process (but now only write a single line to its stdin)

$ spmi connect echo
Hello

View status again

$ spmi status echo
echo (task) - A forever echo command.
      Active: active since 2024-07-13 18:36:49 (0:03:46 ago)
        Path: "/home/leonid/.spmi/echo"
Backend type: screen
  Backend ID: 76113
Wrapper type: default
     Command: cat -
         PID: 76158

Hello

[2024-07-13 18:40:35,153 - Spmi - INFO]
Showed 1 manageables

cat - printed your line to stdout! Also you can see that screen is in screen -ls

$ screen -ls
        76113.SPMI screen echo   (Detached)
1 Socket in /run/screens/S-leonid.

Next, stop echo task

$ spmi stop echo
[2024-07-13 18:42:04,887 - Spmi - INFO]
Stopping manageable "echo"
[2024-07-13 18:42:04,894 - Spmi - INFO]
Stopped 1 manageables

And look at its status one more time

$ spmi status echo
echo (task) - A forever echo command.
      Active: inactive since 2024-07-13 18:42:05 (0:00:54 ago)
        Path: "/home/leonid/.spmi/echo"
Backend type: screen
  Backend ID: 76113
Wrapper type: default
     Command: cat -
         PID: 76158
   Exit code: -2

first

[2024-07-13 18:42:59,899 - Spmi - INFO]
Showed 1 manageables

To remove task, you don't want to use, execute spmi clean

$ spmi clean cal
[2024-07-13 18:44:26,503 - Spmi - INFO]
Cleaning manageable "cal"
[2024-07-13 18:44:26,510 - Spmi - INFO]
Cleaned 1 manageables

SPMI uses regex to match IDs. To remove all loaded examples, execute

$ spmi clean '.*'
[2024-07-13 18:46:38,954 - Spmi - INFO]
Cleaning manageable "ping"
[2024-07-13 18:46:38,962 - Spmi - INFO]
Cleaning manageable "echo"
[2024-07-13 18:46:38,969 - Spmi - INFO]
Cleaned 2 manageables

For advanced usage, read SPMI documentation.