Multiple dependency proposal online in Wiki

[paul]

Scott James Remnant wrote:
> On Tue, 2006-10-31 at 15:19 -0500, Sean Russell wrote:
>
>   
>> I've put my proposal up on the Upstart Wiki, for those who are 
>> interested.
>>
>>         https://wiki.ubuntu.com/in-Upstart_proposal
>>
>>     
> A good start, but ... this doesn't address a few things:
>
>   
>  * What state will the jobs be in?  How can a sysadmin tell what the job
>    is waiting for?
>   
Can you list the events it waits for?
If the job A has:

    start on B,C

then status would give

    job A waits B,C

if job C has already been full filed:

    job A waits B received C

if job C does not exists on the file system:

    job A waits B ignoring C

or plain simple:

    job A waits B

>  * If a job needs both "network-device-up eth0" and "fhs-filesystems",
>    do they have to arrive in a particular order?
>   
No, for the waiting job it self it should not matter in which order the 
events come. I can not think of a job that needs to have received the 
events in a specific order.
>  * How does one "cancel" an event?  The "network-device-down eth0" event
>    would need to cancel out the network-device-up event, and cause it to
>    wait for longer
>   
Would it not be better to change the events to 
"network-device.eth0.down" (or "network-device/eth0/down") and thus also 
"network-device.eth0.up" (or "network-device/eth0/up").

Therefore the basic event is "network-device" with as 'arguments' the 
device and the status. When a "network-device" event is received the 
script checks for which device (eth0) and what it status is (up or 
down). Therefore an "up" cancels automatically a "down" and the other 
way around. This sounds logical to me but I have not thought about the 
implementation of this ;-)

Other similar events I am thinking off:
network-device.[port].[up/down]          eg: network-device.eth0.down
file-system.[fs].[checked/writable/mounted/unmounted]    eg: 
file-system.root.writable
block-device.[block].[added/removed]     eg: block-device.sda.removed

Paul
> Scott
>   
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