[process] prettify & cache AccessDenied failures #1595
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LeoCavaille
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Nice cleanup! We should probably cache the pid list too, i'm not sure it's useful to refresh it at every iteration. According to the dev mode ( 👍 @talwai ) this is by far the most intensive operation of the check. We could maybe cache it for a few iterations ? |
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@remh it's a bit hard to make this design choice, where people could potentially put no-data monitors on top of those metrics. Or maybe hide it behind a feature flag? |
LeoCavaille
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+1 for the feature flag / a TTL parameter for the pid list. |
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@remh implemented, let me know what you think? |
| self.last_pid_cache_ts = {} | ||
| self.pid_cache = {} | ||
| self.pid_cache_duration = int( | ||
| init_config.get( |
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shouldn't that be an instance parameter instead ?
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I think in most cases, this shouldn't be changed so I don't think it's worth the trouble for an instance parameter.
Refactor a bit this check, two noticeable changes: 1. on Windows especially, we get randomly some `AccessDenied` exceptions when trying to look at some processes. Because we iterate on all the processes at every run, it would trigger as many failures *every run*. Once we get this error and `ignore_denied_access` is set to true, we'll not look at it again until DEFAULT_AD_CACHE_DURATION or `access_denied_cache_duration` in the init config. 2. instead of doing some sketchy try/catch over the code, all the psutil-related code that actually gets metric values is wrapped into `psutil_wrapper` which knows how to handle exceptions and known failures. Last remark: before we were setting some metrics to 0 even if we had no values parsed, this is not the case anymore.
The new init_config `pid_cache_duration` is the period during which the agent won't try to refresh the "matching" PID list for each instance. It avoids having to iterate over all the processes every run, the cache is invalidated when: * the deadline expire * or one of the cached process can't be read anymore One would want to lower the cache deadline if he wants to alert on no-data.
LeoCavaille
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Changes Unknown when pulling cc5a67b on leo/processcheck into ** on master**. |
Refactor a bit this check, two noticeable changes:
AccessDeniedexceptionswhen trying to look at some processes. Because we iterate on all the
processes at every run, it would trigger as many failures every run.
Once we get this error and
ignore_denied_accessis set to true, we'llnot look at it again until DEFAULT_AD_CACHE_DURATION or
access_denied_cache_durationin the init config.psutil-related code that actually gets metric values is wrapped into
psutil_wrapperwhich knows how to handle exceptions and knownfailures.
Last remark: before we were setting some metrics to 0 even if we had no
values parsed, this is not the case anymore.