Add global label length limits#85
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1. config/config.go — Default limits of 1 MiB - Added LabelNameLengthLimit: 1 << 20 and LabelValueLengthLimit: 1 << 20 to DefaultGlobalConfig - Added fallback logic in GlobalConfig.UnmarshalYAML so a partial global config (one that doesn't set these fields) still gets the defaults, matching the pattern already used for ScrapeInterval, EvaluationInterval, etc. 2. scrape/scrape.go — Pre-construction panic prevention Added a check before p.Labels(&lset) that rejects metrics whose raw text exceeds 16 MiB. Since the encoding format panics for any individual string > 16 MiB, and no single label value can be longer than the total metric string, len(met) > 1<<24 is a safe guard. The configured 1 MiB limit then catches the normal cases in verifyLabelLimits. 3. storage/remote/write_handler.go — Configurable limits in RW receiver - Added labelNameLengthLimit and labelValueLengthLimit fields to writeHandler - Added two int parameters to NewWriteHandler - Added checkLabelLengths() helper that enforces the limits - Wired the check into both v1 write() and v2 appendV2() paths 4. web/api/v1/api.go — Wires global config limits to RW handler Passes cfg.GlobalConfig.LabelNameLengthLimit and LabelValueLengthLimit from the config to NewWriteHandler at construction. 5. promql/functions.go — Guards in label_replace and label_join Added explicit checks for the 16 MiB encoding limit before the lb.Labels() call. The evaluator's existing defer ev.recover() already converts panics to errors, but these checks give a clear, explicit error message instead. Tests - Updated config/config_test.go to expect the new 1 MiB defaults in TestGetScrapeConfigs - Updated all ~16 NewWriteHandler call sites in write_handler_test.go to pass 0, 0 (no limit) for the new parameters
bboreham
requested review from
bwplotka,
cstyan,
roidelapluie and
tomwilkie
as code owners
|
Issue is prometheus#16525 |
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Added a check before p.Labels(&lset) that rejects metrics whose raw text exceeds 16 MiB. Since the encoding format panics for any individual string >
16 MiB, and no single label value can be longer than the total metric string, len(met) > 1<<24 is a safe guard. The configured 1 MiB limit then
catches the normal cases in verifyLabelLimits.
Passes cfg.GlobalConfig.LabelNameLengthLimit and LabelValueLengthLimit from the config to NewWriteHandler at construction.
Added explicit checks for the 16 MiB encoding limit before the lb.Labels() call. The evaluator's existing defer ev.recover() already converts panics
to errors, but these checks give a clear, explicit error message instead.
Tests
Which issue(s) does the PR fix:
Does this PR introduce a user-facing change?