[tor-bugs] #16296 [Onionoo]: Implement lock file in a more robust way

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#16296: Implement lock file in a more robust way
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     Reporter:  karsten  |      Owner:
         Type:  defect   |     Status:  needs_review
     Priority:  normal   |  Milestone:
    Component:  Onionoo  |    Version:
   Resolution:           |   Keywords:
Actual Points:           |  Parent ID:
       Points:           |
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Comment (by leeroy):

 True it does stick to the 4GB. That's what the -Xmx flag does. It says to
 the JVM, you may use 4GB, even if you don't need it, which is most of the
 time for one-time update, or hourly periodic. In fact, the only time when
 4GB is actually needed is for processing archives (~3.7GB/avg for a single
 month). The problem is this trashes the OS cache which could be used for
 better things (like disk cache), or web frontend cache. Not to mention
 what would happen if you introduce another dependency, like a db process.
 which relies on the OS memory management and caching.

 I've touched on this topic elsewhere so not to worry--it's a major
 concern.

 Oh, I've also made the LockFile even more robust for permission like
 problems. I attach the revision here (and I'm testing it on a running
 instance). I see there aren't any unit tests for this component. If you
 would like some just mention it here. The permission handling addition
 additionally deals with #16401. If you would prefer more separation please
 do mention it here as well.

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/16296#comment:6>
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