[squid-users] Survey on assertions: When the impossible happens

[Yuri Voinov]

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29.02.16 23:22, Marcus Kool пишет:
>
>> * Choices.
>>
>> Overall, there are three options for handling an impossible situation:
>>
>> 1. Quit Squid process. This is what Squid does today in most cases.
>>     When the impossible happens, you get a crash. Very predictable.
>>     No malformed/corrupted/misleading HTTP messages (some are truncated).
>>     No memory leaks.
>>
>> 2. Quit the current processing sequence but keep Squid process running,
>>     assuming that [most] other processing sequences are not affected.
>>     [If you are familiar with programming, this is done by throwing
>>     exceptions instead of asserting and catching those exceptions at
>>     "processing sequence" boundaries].
>>
>> 3. Keep executing the current processing sequence, assuming that the
>>     assertion was wrong or unimportant. This is what you might be
>>     suggesting above. When the impossible happens, you may get a crash,
>>     memory leaks, malformed/corrupted/misleading HTTP messages, or normal
>>     behavior, depending on the assertion and traffic.
>>
>> IMO, we should make #2 the default, but make the choice between all
>> three options configurable by the admin (without recompiling Squid).
>
> Let me suggest #4 :
>
> immediately execute an external program that calls gdb or any other
debugger
> which produces a stack trace of all squid processes and then do #1 or #2.
>
> The stack dumps will be save in an assertion failure log file which admins
> can send to Squid developers.
>
> This will speedup the debugging and fixing procedure.
>
> Finally, there must be a mechanism that warns admins that an assertion
failure
> happened.  This is not trivial since an admin does not look every day
> in the squid log file.
Hmmmmmmm...... some shell scripting+cron+sendmail can't save the giants
of thought? ;)
>
> Marcus
> _______________________________________________
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> squid-users at lists.squid-cache.org
> http://lists.squid-cache.org/listinfo/squid-users

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