ipctools 0.2.1

Inter-process communication tools.

Ipctools is a library to facilitate inter-process communication.

Installation

pip install ipctools

Usage

The store API is used to get or set values in a key-value store. This store is implemented as a temporary file on the system. The default file location may be overridden with the IPCTOOLS_STORE environment variable.

Set, and get a value from the store.

from ipctools import store

store.set_value("my_key", "my_value")
value = store.get_value("my_key")
assert value == "my_value"

Setting a value updates it if exists.

store.set_value("my_key", "my_value_1")
store.set_value("my_key", "my_value_2")
value = store.get_value("my_key")
assert value == "my_value_2"

However, creating a value will fail if it already exits. You can perform leader election across multiple processes by having each one try to set a value. Only one process will succeed, so that one can be the leader.

import os

from ipctools import store

is_leader = store.create_value("leader", str(os.getpid()))

Since the value of leader was set to the process ID of a single process, any process can also determine who the leader is.

def am_i_the_leader() -> bool:
    return store.get_value("leader") == str(os.getpid())

If mutliple processes try to set a value at the same time, some of them may fail. You can try to set a value with retries.

store.try_set_value("my_key", "my_value", retries=2)