fix(inputs.procstat): Isolate process cache per filter to fix tag collision #18144
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…lision
When multiple filters match the same process (PID), each filter now
maintains its own isolated process cache entry. This ensures metrics
are emitted with the correct filter tag instead of reusing the cached
process from the first matching filter.
Additionally fixes:
- Variable shadowing where inner `running` boolean shadowed outer
`running` map in gatherNew()
- Potential nil pointer dereference when ProcessName was configured
in new-style filter mode (setTag called before process initialized)
telegraf-tiger
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added
area/procstat
fix
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Summary
The process cache was keyed only by PID
(map[pid]process). When multiple filters matched the same process, the second filter would find the cached process from the first filter and reuse it, emitting metrics with the wrong filter tag.Fix:
Changed the process cache to a nested map keyed by filter name and PID
(map[string]map[pid]process). Each filter now:Additional Fixes:
if running, err := gp.IsRunning()shadowed the outerrunningmap variable. Renamed toisRunning.process.setTag("process_name", ...)beforeprocesswas initialized (inside theif !foundblock, beforeprocess = &proc{...}). Fixed by settingtags["process_name"]directly in the tags map.Performance Impact:
Negligible - one additional O(1) map lookup per filter per Gather() call. The
filterProcsreference is cached outside the inner loop, so per-process lookup cost is unchanged.Checklist
Related issues
resolves #18041