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Talk:Run as a daemon or service: Difference between revisions
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Simplified description
(→Doh, use screen!: it is not about existing tools to daemonize a program but about about the capability to build such a tool) |
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:: This is not about cluttering your interactive screen sessions with daemons, but screen as a dedicated tool for having daemons running. Like under a different user ID from your account, etc! To interact with the daemons, you might "su" to a different account and attach a different screen session. Such screen sessions can be arranged to start at boot time with daemons in them. [[Special:Contributions/24.85.131.247|24.85.131.247]] 04:51, 17 January 2012 (UTC)
::: two screens is also clutter. if i want to run the daemon as a user that is already running screen, i get an additional screen session which adds an extra step every time i want to connect to the interactive session. and if i want to run multiple daemons do i run a separate screen session for each? or all in one session with multiple terminals? what if screen gets stuck and you can no longer connect to it to run additional daemons? yes, i have seen that happen. the only way out was to kill screen which would bring down all the daemons inside.
:::: I haven't used screen in many years, yet I certainly do remember bugs like that. But, surprisingly, it seems to be quite actively maintained.There is quite a bit of recent activity in the GIT repo: http://git.savannah.gnu.org/cgit/screen.git What version are you using? [[Special:Contributions/24.85.131.247|24.85.131.247]] 07:31, 17 January 2012 (UTC)
:::: Then again, there are a LOT of un-investigated bugs in the database also (including one generic one about the hangs and one about attaching from another user and tty permissiosn). The most recent bug was reported a few days ago: someone ran gcc -Wall and found a few issues. That's pretty terrible for an old project.[[Special:Contributions/24.85.131.247|24.85.131.247]] 08:02, 17 January 2012 (UTC)
:::if you "su" to a user other than root, then you keep using your existing terminal and screen can't connect because the new user does not have permission to access the terminal:
$ screen
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::: so multiple daemons in one screen session is not practical either. there are ways around it (eg. by running <code>script</code>) but that's just another complication.
::: i am afraid we just have to agree to disagree. in my view screen is for interactive sessions. a daemon is not interactive, and there are better tools out there to run programs in the background than screen. either way, this task is not about any of those existing tools but about the capability of a language to build such a tool--[[User:EMBee|eMBee]] 06:29, 17 January 2012 (UTC)
: From my perspective, the problem with screen is that it is a manual solution at all. Daemons should run without having someone start them up by hand; after all, if it is a true daemon then it will have been set to be started automatically upon reboot of the machine (or on demand by some automated code that is itself auto-started). While I suppose I could automate screen's startup with the use of expect, the resulting hacked together lash up(/ball of mud/screaming horror from the depths) is enough to give me shivers just thinking about it. Screen is ''not'' a solution to this problem. –[[User:Dkf|Donal Fellows]] 09:43, 17 January 2012 (UTC)
:: screen has arguments to start a detached session, and run a command in that session. <code>screen -dmS <session_name> /path/to/your/server</code>. [[Special:Contributions/24.85.131.247|24.85.131.247]] 04:24, 18 January 2012 (UTC)
===Simplified description===
I propose we just simplify the task description as follows:
A daemon is a service that runs in the background independent of a users login session. The task is to demonstrate the steps that a program needs to take run as a background daemon or service.
[[User:Markhobley|Markhobley]] 12:49, 29 March 2013 (UTC)
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