| [11:19] <keesj> Hi | |
| [11:19] <Keybuk> hey | |
| [11:22] <keesj> I am playing with upstart. I am trying to implement a state machine for my system | |
| [11:23] <keesj> I wonder if it makes sence :). the big idea would be to emit events from userland or the kernel and handle upon them in upstart | |
| [11:24] <keesj> I have a 3 gui apps that will run (not at the same time) | |
| [11:27] <keesj> I would like to be able to emit "high" level events "start_mass-storage-app" and translate that into a few command (insmods perhaps) and starting a gui | |
| [11:27] <keesj> can I emit such event from within a job | |
| [11:28] <keesj> simply saying.. can I emit events from withing a jobs | |
| [11:36] <Keybuk> sure | |
| [11:38] <keesj> by calling initctl ? | |
| [11:40] <Keybuk> right | |
| [11:41] <keesj> there is no "emit" command" | |
| [11:46] <Keybuk> there is | |
| [11:46] <Keybuk> initctl emit | |
| [12:12] <keesj> thanks | |
| [12:12] <keesj> I installed upstart in a different directory... I need to prefix the initctl command :( | |
| [12:12] <Keybuk> you can make an "emit" command by just symlinking to initctl :p | |
| [12:12] <Keybuk> right | |
| [12:13] <Keybuk> fixing that is on the TODO | |
| [12:13] <keesj> that's nice | |
| [12:21] <keesj> and would there be a way to store the current states so I can ask it again later? | |
| [12:22] <Keybuk> how do you mean? | |
| [12:23] <keesj> just like runlevels work ( that you can ask the current runlevel) | |
| [12:23] <Keybuk> still not 100% following | |
| [12:23] <keesj> I would like to keep some variable to implement my state | |
| [12:24] <keesj> if (in_mass_storage) and usb unplugged -> rmmod ... | |
| [12:24] <keesj> in_mass_storage would be a state | |
| [12:26] <keesj> in the sample scripts "they" do set $(runlevel --set 1 || true) | |
| [12:27] <keesj> to determine if an event gets handled based on the previous runlevel (this is sample code named rc1) | |
| [12:28] <Keybuk> right, I'm kinda trying to get to that point | |
| [12:28] <Keybuk> where upstart has states that are true or false | |
| [12:28] <keesj> you are one of the developers, cool | |
| [12:29] <Keybuk> heh, the upstart developer | |
| [12:29] <keesj> yo! | |
| [12:30] <keesj> I am currently testing by using a qemu (I first tried a chroot ) but the apparently was not the best way to do things | |
| [12:30] <Keybuk> I just have it installed by default | |
| [12:31] <Keybuk> it replaces sysvinit well enough | |
| [12:31] <Keybuk> you can carry on running the old init scripts while playing/developing | |
| [12:32] <keesj> I am playing with it for mamona so it is an embedded platform (under arm) | |
| [12:33] <keesj> do you happen to know this package? http://smc.sourceforge.net/ (state machine compiler) | |
| [12:39] <Keybuk> I don't, no | |
| [12:41] <keesj> I used it a lot to create state machines. but basicaly you need "previous_state" + event to implement this | |
| [12:42] <Keybuk> right | |
| [12:42] <Keybuk> depends what you want to do, really | |
| [12:43] <keesj> the "quick" hack would be to misues the initctl to tell init to change it's own "environement" | |
| [12:44] <keesj> thanks for your time btw (I really apreaciate it) | |
| [12:44] <Keybuk> right, but I'm not sure I fully understand what you want to achieve | |
| [12:47] <keesj> hmm . perhaps I am just thinking the wrong way around. let me try to give a simple example | |
| [12:51] <keesj> my system can have twoo states "video playback" and "mass storage". | |
| [12:52] <keesj> if somebody presses the power button while in mass storage I don't like that so I would like to ignore a "power" event when in storage mode. | |
| [12:53] <keesj> I was thinking in the line of creating a "button" event handler that listend to power_on power_off event | |
| [12:54] <keesj> other events would be something like usb_connected (being a good reason to switch to mass storage) | |
| [13:00] <keesj> I think I am taling about level events | |
| [13:00] <Keybuk> what other kinds of decision would you make based on these states though/ | |
| [13:04] <keesj> whell I have a few of those event flying in (usb state changes, button presses, system update event) I was also thinking of using this state when going in "suspend" mode | |
| [13:04] <keesj> so that when I wakeup I know what program to start again | |
| [13:05] <Keybuk> when suspending why do you need to stop programs? | |
| [13:06] <keesj> good questions :p | |
| [13:09] <keesj> currenty I had to do it because I don't get events when in suspend , so if the device is in video mode , I suspend , and plug it to a computer , I miss the "connected" event | |
| [13:09] <keesj> (just like udev meesd to cache the events generated by the kernel , I guess this is not the scop of upstart :p | |
| [13:13] <keesj> I am getting there ! | |
| [13:14] <Keybuk> not entirely sure yet what the scope of upstart is ;) | |
| [13:16] <keesj> haha | |
| [13:17] <keesj> the code looks very clean | |
| [14:12] <keesj> are you at fosdem? | |
| [14:20] <Keybuk> no | |
| [14:23] <Keybuk> I've never been to one of those | |
| [14:37] <Keybuk> http://upstart.ubuntu.com/wiki/RemoveEventArguments | |
| [14:37] <keesj> I can be nice :op | |
| [14:37] <Keybuk> Any objection? no? good! :o) | |
| [14:39] <keesj> haha | |
| [14:39] <keesj> it | |
| [14:41] <keesj> I really just should al be programmed in lua | |
| [14:42] <Keybuk> why? | |
| [14:44] <keesj> I see plenty discussion about creating, "combined events" or other other structs that would be possible if upstart used a scripting language for the events definitions | |
| [14:44] <keesj> but the current aproach is also pretty clean i guess | |
| [14:46] <keesj> >>from (tty-added or cua-added) and foo<< does that get interpreted every time an event would come? | |
| [14:52] <Keybuk> the string? no | |
| [14:52] <Keybuk> it's compiled into a match tree in memory | |
| [14:53] <keesj> hmm that you can not replace by lua :) | |
| [14:53] <Keybuk> what would lua gain though? | |
| [14:56] <keesj> in this case nothing. but just like the current script command you could script the behaviour (if an event is consummed by an handler) | |
| [15:04] <keesj> my system looks a little like the stoplight (the left image) http://smc.sourceforge.net/Images/SmcEx4_Stoplight.png I get the same type of events (like a timeout ). I see very whell how to perform the "start,turn light etc" . | |
| [15:05] <keesj> you get the same "message" but want to perform something different(if you want me to stop just say so , I am really trying to find a awy to do it) | |
| [15:06] <keesj> I have put the different events in an event_handler that performs the few functions | |
| [15:06] <keesj> so I can not emit "switch_from_a_to_b" | |
| [15:08] <Keybuk> hmm | |
| [15:08] <Keybuk> currently Upstart's event matching is more functional than procedural | |
| [15:09] <Keybuk> ie. you describe the state in which the job is running | |
| [15:09] <Keybuk> inside the job itself, you have a shell script, so it's procedural | |
| [15:09] <keesj> Yes , I Have the feeling I really am missing the point :p | |
| [15:09] <Keybuk> I'm not sure I've got the point ;) | |
| [15:09] <keesj> AM I trying to misue the system? | |
| [15:09] <keesj> missue | |
| [15:09] <Keybuk> I'm not quite sure what you're trying to do yet | |
| [15:11] <keesj> in a perfect work I would like to say "emit go_into_mass_storage" where ever you come from | |
| [15:12] <Keybuk> you wouldn't use an event like that | |
| [15:12] <Keybuk> I'd define mass_storage as a state/job | |
| [15:12] <Keybuk> so "start mass_storage" | |
| [15:14] <keesj> yes I have this part http://paste-it.net/6595 | |
| [15:15] <keesj> so do I need to create a userland progress saying "emit stop_mass_storage" "emit start_video" | |
| [15:17] <keesj> with just the start/stop the system looks like /etc/init.d/mass_storage [start|stop] | |
| [15:18] <keesj> or would start mass_storage stop video? | |
| [15:19] <keesj> the backwards compatible scripts use wmtp to "know" what the current runlevel is | |
| [15:29] <keesj> I am getting there ... /initctl list | |
| [15:29] <keesj> shows a list of active tasks, I can only have one state active at the time..... | |
| [15:30] <Keybuk> so you'd make your states start and stop each other? | |
| [15:30] <Keybuk> or be started and stopped by the same events | |
| [15:31] <keesj> I will listen for event use the initctl to know the current state and react as supposed | |
| [15:32] <keesj> I currently implemented it a separate jobs that are triggered by events (the switching between states) | |
| [15:33] <keesj> So I guess the second option | |
| [15:34] <keesj> perhaps I might even use the list to do sanity checks | |
| [15:53] <keesj> I will try to hack a version and try to post it to the list | |
| [16:01] <Keybuk> shiny | |
| [16:05] <keesj> I hope it wil work. (that there are no race cases...) | |
| [16:06] <keesj> it requires a state to keep running apparently a jobs that is started and exits is in a "stop" state again | |
| [16:14] <Keybuk> (gdb) p *((EventOperator *)job->start_on->node->left) | |
| [16:14] <Keybuk> $5 = {node = {parent = 0x662720, left = 0x0, right = 0x0}, type = EVENT_MATCH, | |
| [16:14] <Keybuk> value = 0, name = 0x662670 "wibble=foo bar", env = 0x0, event = 0x0, | |
| [16:14] <Keybuk> blocked = 0} | |
| [16:14] <Keybuk> (gdb) p *((EventOperator *)job->start_on->node->right) | |
| [16:14] <Keybuk> $6 = {node = {parent = 0x662720, left = 0x0, right = 0x0}, type = EVENT_MATCH, | |
| [16:14] <Keybuk> value = 0, name = 0x6628a0 "wobble=foo bar", env = 0x0, event = 0x0, | |
| [16:14] <Keybuk> blocked = 0} | |
| [16:14] <Keybuk> (tangent: | |
| [16:14] <Keybuk> damn I was on good form when I wrote this, I predicted I'd need something a year down the line) | |
| [16:14] <Keybuk> that was from | |
| [16:15] <Keybuk> "wibble=foo bar" or wobble="foo bar" | |
| [16:15] <Keybuk> so it handles quoting sensibly | |
| [16:21] <keesj> can I get the event name inside my scripts? | |
| [16:22] <keesj> UPSTART_EVENT... | |
| [16:22] <Keybuk> right | |
| [16:22] <Keybuk> $UPSTART_EVENTS in trunk | |
| [16:33] <keesj> week-end here. thanks a lot for the help! | |
| [16:33] <Keybuk> enjoy | |
| [16:33] <keesj> thanks | |
| === ion___ is now known as ion_ | |