Re: [systemd-devel] start service only on specific exit status of some prog
On Thu, 25.08.11 13:09, Nick Jones (nick.jo...@network-box.com) wrote: On Wed, 2011-08-24 at 21:21 +0200, Lennart Poettering wrote: On Wed, 24.08.11 21:12, Marius Tolzmann (tolzm...@molgen.mpg.de) wrote: On 24.08.2011 18:52, Lennart Poettering wrote: Hmm, yeah, if ExecStartPre= we put the unit in failure mode. So, let me see if I got this right: you are looking for something like ExecStartPre= but twhere the program when it returns non-zero should just cause the service to be skipped but not be put in failure state? Yes. that's my request. something like ConditionExec=/bin/true and ConditionExec=/bin/false so i can implement any thinkable logic outside of systemd and still maintain access to all features like Restart= etc. I thought this may be an easy way to expand the already existent conditions (ConditionPathExists= etc.) without implementing too many special conditional tests in systemd itself. (e.g. check if the current hostname matches some pattern - which was my original issue i tried to solve) 8) I have now added this to the TODO list. It won't be easy to add this though, as execution extrernal processes synchronously is not an option. More likely I'll add an additional prefix char to ExecStart= (like -) which would indicate skip-on-fail or so. Lennart Would it make sense to emit a virtual unit label if a given unit fails? That already exists with OnFailure=. Lennart -- Lennart Poettering - Red Hat, Inc. ___ systemd-devel mailing list systemd-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/systemd-devel
Re: [systemd-devel] start service only on specific exit status of some prog
On Wednesday 24 August 2011 17:25:40 Marius Tolzmann wrote: On 24.08.2011 16:01, Lennart Poettering wrote: On Tue, 02.08.11 17:06, Marius Tolzmann (tolzm...@molgen.mpg.de) wrote: is there a way to execute a program and take its exit status to evaluate the condition? like ConditionExec or whatever. is this already possible without getting a failed service? Hmm, so I think we should make sure that systemd unit files don't become a programming language. i.e. there needs to be a limit on what we want to allow to be expressed in unit files. I am tempted to say that checks like this are probably beyond that limit, and fall into the domain where shell scripts should be used. I.e. write a tiny shell script that is executed in ExecStartPre invokes your tool, checks the return code and then fails if needed. Hi... thanks for the reply.. i really don't want to implement complex checks within unit files.. but currently systemd lacks a clean possibility to implement complex checks outside of unit files. snip... Why not have the complex logic run before the system reboots and chaneg the systemd dependancies? For example in our application a TV card is optional. We could check at run time during boot, but it seemed cleaner to us to change the dependancies. Barry ___ systemd-devel mailing list systemd-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/systemd-devel
Re: [systemd-devel] start service only on specific exit status of some prog
On Tue, 02.08.11 17:06, Marius Tolzmann (tolzm...@molgen.mpg.de) wrote: hi.. since conditions specifying wheter a service should start are somehow limited to the existence of some files/directories/etc. i was searching for something more complex to handle conditional service starts. is there a way to execute a program and take its exit status to evaluate the condition? like ConditionExec or whatever. currently we need a service that only starts if the current hostname matches some value, i.e. only start service on hostA. or we need to start a service only if some special IP is configured on a network interface. is this already possible without getting a failed service? Hmm, so I think we should make sure that systemd unit files don't become a programming language. i.e. there needs to be a limit on what we want to allow to be expressed in unit files. I am tempted to say that checks like this are probably beyond that limit, and fall into the domain where shell scripts should be used. I.e. write a tiny shell script that is executed in ExecStartPre invokes your tool, checks the return code and then fails if needed. Lennart -- Lennart Poettering - Red Hat, Inc. ___ systemd-devel mailing list systemd-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/systemd-devel
Re: [systemd-devel] start service only on specific exit status of some prog
On 24.08.2011 16:01, Lennart Poettering wrote: On Tue, 02.08.11 17:06, Marius Tolzmann (tolzm...@molgen.mpg.de) wrote: is there a way to execute a program and take its exit status to evaluate the condition? like ConditionExec or whatever. is this already possible without getting a failed service? Hmm, so I think we should make sure that systemd unit files don't become a programming language. i.e. there needs to be a limit on what we want to allow to be expressed in unit files. I am tempted to say that checks like this are probably beyond that limit, and fall into the domain where shell scripts should be used. I.e. write a tiny shell script that is executed in ExecStartPre invokes your tool, checks the return code and then fails if needed. Hi... thanks for the reply.. i really don't want to implement complex checks within unit files.. but currently systemd lacks a clean possibility to implement complex checks outside of unit files. I first tried the StartExecPre= approach.. but it turns out to be somehow destructive in combination with Restart=always.. and you end with a failed service. Currently we have a unit that starts a script which starts other units via systemctl.. it works.. but this too is not really nice, because you can still directly start those unit files by mistake and they won't complain about any external conditions.. since i can't figure out a nice way to evaluate complex conditions i asked for some help here and proposed something like ConditionExec=/some/prog to be able to implement some small c-program to do complex condition checking outside of systemd... We just need a way to integrate the result without loosing some cool systemd features.. 8) may be this could be implemented in future releases or is this a real no-go? regards, marius.. ___ systemd-devel mailing list systemd-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/systemd-devel
Re: [systemd-devel] start service only on specific exit status of some prog
On 24.08.2011 18:52, Lennart Poettering wrote: Hmm, yeah, if ExecStartPre= we put the unit in failure mode. So, let me see if I got this right: you are looking for something like ExecStartPre= but twhere the program when it returns non-zero should just cause the service to be skipped but not be put in failure state? Yes. that's my request. something like ConditionExec=/bin/true and ConditionExec=/bin/false so i can implement any thinkable logic outside of systemd and still maintain access to all features like Restart= etc. I thought this may be an easy way to expand the already existent conditions (ConditionPathExists= etc.) without implementing too many special conditional tests in systemd itself. (e.g. check if the current hostname matches some pattern - which was my original issue i tried to solve) 8) bye, marius.. ___ systemd-devel mailing list systemd-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/systemd-devel
Re: [systemd-devel] start service only on specific exit status of some prog
On Wed, 24.08.11 21:12, Marius Tolzmann (tolzm...@molgen.mpg.de) wrote: On 24.08.2011 18:52, Lennart Poettering wrote: Hmm, yeah, if ExecStartPre= we put the unit in failure mode. So, let me see if I got this right: you are looking for something like ExecStartPre= but twhere the program when it returns non-zero should just cause the service to be skipped but not be put in failure state? Yes. that's my request. something like ConditionExec=/bin/true and ConditionExec=/bin/false so i can implement any thinkable logic outside of systemd and still maintain access to all features like Restart= etc. I thought this may be an easy way to expand the already existent conditions (ConditionPathExists= etc.) without implementing too many special conditional tests in systemd itself. (e.g. check if the current hostname matches some pattern - which was my original issue i tried to solve) 8) I have now added this to the TODO list. It won't be easy to add this though, as execution extrernal processes synchronously is not an option. More likely I'll add an additional prefix char to ExecStart= (like -) which would indicate skip-on-fail or so. Lennart -- Lennart Poettering - Red Hat, Inc. ___ systemd-devel mailing list systemd-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/systemd-devel
Re: [systemd-devel] start service only on specific exit status of some prog
On 24.08.2011 21:21, Lennart Poettering wrote: On Wed, 24.08.11 21:12, Marius Tolzmann (tolzm...@molgen.mpg.de) wrote: On 24.08.2011 18:52, Lennart Poettering wrote: Hmm, yeah, if ExecStartPre= we put the unit in failure mode. So, let me see if I got this right: you are looking for something like ExecStartPre= but twhere the program when it returns non-zero should just cause the service to be skipped but not be put in failure state? Yes. that's my request. I have now added this to the TODO list. It won't be easy to add this though, as execution extrernal processes synchronously is not an option. More likely I'll add an additional prefix char to ExecStart= (like -) which would indicate skip-on-fail or so. I think you mean ExecStartPre= here!? And thanks for considering implementing this feature sometime.. 8) regards, marius.. ___ systemd-devel mailing list systemd-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/systemd-devel
Re: [systemd-devel] start service only on specific exit status of some prog
On Wed, 24.08.11 23:54, Marius Tolzmann (tolzm...@molgen.mpg.de) wrote: On 24.08.2011 21:21, Lennart Poettering wrote: On Wed, 24.08.11 21:12, Marius Tolzmann (tolzm...@molgen.mpg.de) wrote: On 24.08.2011 18:52, Lennart Poettering wrote: Hmm, yeah, if ExecStartPre= we put the unit in failure mode. So, let me see if I got this right: you are looking for something like ExecStartPre= but twhere the program when it returns non-zero should just cause the service to be skipped but not be put in failure state? Yes. that's my request. I have now added this to the TODO list. It won't be easy to add this though, as execution extrernal processes synchronously is not an option. More likely I'll add an additional prefix char to ExecStart= (like -) which would indicate skip-on-fail or so. I think you mean ExecStartPre= here!? Indeed. Sorry for the confusion. And thanks for considering implementing this feature sometime.. 8) Lennart -- Lennart Poettering - Red Hat, Inc. ___ systemd-devel mailing list systemd-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/systemd-devel
[systemd-devel] start service only on specific exit status of some prog
hi.. since conditions specifying wheter a service should start are somehow limited to the existence of some files/directories/etc. i was searching for something more complex to handle conditional service starts. is there a way to execute a program and take its exit status to evaluate the condition? like ConditionExec or whatever. currently we need a service that only starts if the current hostname matches some value, i.e. only start service on hostA. or we need to start a service only if some special IP is configured on a network interface. is this already possible without getting a failed service? bye m. -- Dipl.-Inf. Marius Tolzmann marius.tolzm...@molgen.mpg.de --.-- MPI f. molekulare Genetik | Ihnestrasse 63-73, D-14195 Berlin | == MarIuX GNU/Linux == Phone: +49 (0)30 8413 1709| --^-- God put me on earth to accomplish a certain number of things. Right now I am so far behind.. ..I will never die. by calvin from calvinhobbes ;) ___ systemd-devel mailing list systemd-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/systemd-devel
