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Re: Best (simplest) way to share data (Posting On Python-List Prohibited)

From Lawrence D'Oliveiro <ldo@nz.invalid>
Newsgroups comp.lang.python
Subject Re: Best (simplest) way to share data (Posting On Python-List Prohibited)
Date 2024-07-07 01:43 +0000
Organization A noiseless patient Spider
Message-ID <v6crrk$1kfb$6@dont-email.me> (permalink)
References <9a8nlk-jb81.ln1@q957.zbmc.eu>

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On Sat, 6 Jul 2024 08:28:41 +0100, Chris Green wrote:

> One fairly obvious way is to have single process/script which reads the
> A2D values continuously and writes them to a file.  All other scripts
> then read from the file as needed, a simple file lock can then be used
> to prevent simultaneous access (well, simultaneous access when the
> writing process is writing).

The thing with a file is, it persists even when the collector process is 
not running. Do you want data that persists when the collector process is 
not running?

Is this a history of values, or just a snapshot of current values? A 
history of values could be written to a database. Databases provide their 
own transactions and interlocking to prevent readers from reading partial 
updates.

If it’s a snapshot of current values, that does not persist when the 
collector process is not running, then why not just keep the data in the 
memory of the collector process, and have it concurrently listen on a 
socket for connections from readers requesting a copy of the current data?

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Thread

Best (simplest) way to share data between processes Chris Green <cl@isbd.net> - 2024-07-06 08:28 +0100
  Re: Best (simplest) way to share data between processes Gordinator <gordinator@gordinator.org> - 2024-07-06 20:03 +0100
  Re: Best (simplest) way to share data between processes Piergiorgio Sartor <piergiorgio.sartor.this.should.not.be.used@nexgo.REMOVETHIS.de> - 2024-07-06 21:32 +0200
    Re: Best (simplest) way to share data between processes Chris Green <cl@isbd.net> - 2024-07-08 13:52 +0100
  Re: Best (simplest) way to share data (Posting On Python-List Prohibited) Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-07-07 01:43 +0000
    Re: Best (simplest) way to share data (Posting On Python-List Prohibited) Chris Green <cl@isbd.net> - 2024-07-08 13:56 +0100
      Re: Best (simplest) way to share data (Posting On Python-List Prohibited) Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-07-09 05:52 +0000
      Re: Best (simplest) way to share data Chris Green <cl@isbd.net> - 2024-07-09 11:02 +0100
  Re: Best (simplest) way to share data between processes Barry <barry@barrys-emacs.org> - 2024-07-07 23:27 +0100
  Re: Best (simplest) way to share data between processes MRAB <python@mrabarnett.plus.com> - 2024-07-07 23:47 +0100
  Re: Best (simplest) way to share data between processes Barry Scott <barry@barrys-emacs.org> - 2024-07-08 09:34 +0100
  Re: Best (simplest) way to share data between processes Left Right <olegsivokon@gmail.com> - 2024-07-07 23:55 +0200

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