Re^3: File Locking plus delete Lockfile question

At one point in time, this ["checkin/checkout"] system will cease to exist.

Is there any other part of your application that will be able to unambigously detect/determine this time? If so, then can the cleanup code be inserted there? Or could a customer reactivate any checkin/out system at any time in the future?

Even in the latter case, I think you should be able to clean up inactive lockfiles if the cleanup code and the lockfile creation code are both protected by another application-wide lockfile (which never needs to be deleted).

Caveat: I haven't tried any of this out! I hope that my theoretical mullings will be of some use anyway :-)

--
use JAPH;
print JAPH::asString();

Comment on Re^3: File Locking plus delete Lockfile question

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Re^4: File Locking plus delete Lockfile question by rovf (Priest) on Feb 12, 2009 at 15:21 UTC
Is there any other part of your application that will be able to unambigously detect/determine this time? Yes, but it is a bit inconvenient (that part would first have to identify the host where the respective instance had been executed, and while this is technically possible, it is a bit "against the priciples" of the dispatching tools, which adhere the principle that the manager should not care where its instances are executed). But if necessary, it can be done, and this would have been my "plan B" if the locking policy would not have worked out. Fortunately, after the precious comment of JavaFan, I think my revised design is sound and will do what I expected (I still need to test it, of course). -- Ronald Fischer <ynnor@mm.st>	[reply]

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Re^4: File Locking plus delete Lockfile question
by rovf (Priest) on Feb 12, 2009 at 15:21 UTC

Is there any other part of your application that will be able to unambigously detect/determine this time?

Yes, but it is a bit inconvenient (that part would first have to identify the host where the respective instance had been executed, and while this is technically possible, it is a bit "against the priciples" of the dispatching tools, which adhere the principle that the manager should not care where its instances are executed). But if necessary, it *can* be done, and this would have been my "plan B" if the locking policy would not have worked out.

Fortunately, after the precious comment of JavaFan, I think my revised design is sound and will do what I expected (I still need to test it, of course).

--
Ronald Fischer <ynnor@mm.st>

[reply]