74 lines
2.0 KiB
Markdown
74 lines
2.0 KiB
Markdown
timeout-interrupt
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=================
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Works like ruby's timeout, but interrupts *every call*, also syscalls, which blocks the hole ruby-process.
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It uses POSIX's alarm and traps ALRM-signals.
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Known limitations bacause of alarm and ALRM are, that you can not use alarm or trap ALRM in the same time.
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Scopes
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======
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If you need scopes with inner and outer time outs, you should know:
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The first timed out Timeout will be raised:
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include TimeoutInterrupt
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timeout(1) { # Will be raised
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timeout(10) { sleep 2 } # Will not be raised
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}
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If you want to know, which was raised, you need custom exceptions:
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class CustomErrorWillBeRaised <Exception
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end
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class CustomErrorNotRaised <Exception
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end
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include TimeoutInterrupt
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timeout( 1, CustomErrorWillBeRaised) { # Will be raised again
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timeout( 10, CustomErrorNotRaised) { sleep 2 } # Will not be raised
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}
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Problems
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========
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Memory-Leaks and missing clean up
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---------------------------------
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Syscalls can allocate memory.
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If you interrupt a syscall, which then cannot free his allocations, it will result in a memory leak.
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If it opens a file, while it reads, a time out occurs, the file will not automatically be closed.
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So, you should only use it, if your process will die after interrupt or if you are sure, that your call never allocate memory or opens a file.
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You could also publish informations about opened files, that it could be cleaned up later.
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Every time, a process dies, all his memory will be freed and every file will be closed, so let your process die and you should be safe.
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Exception-handling
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------------------
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Timeouts can break your exception-handling! You should not handling exception while you wait for a timeout:
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include TimeoutInterrupt
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timeout(1) {
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begin
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transaction_begin
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do_something
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ensure
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clean_up
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transaction_end
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end
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}
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Same happens, if clean\_up will raise an exception, so handle it in the same way.
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And same problem you have with ruby's `Timeout.timeout`.
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Copyleft
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=========
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Copyright (c) 2021 Denis Knauf. See LICENSE.txt for further details. |