max line lengths (component + tenant overrides)

[owen-d]

What

Adds flag and per tenant limits for maximum line lengths.

Also includes some refactoring for the distributor pkg to isolate logic & make it more maintainable.

Closes #1387

Distributor

distributor.max-line-size: supports sizes like 10mb, 10MB, 10Mb, 10mB, 10 MB, etc.

Tenant overrides

max_line_size: 256kb

Local testing works as expected

[codecov-io]

Codecov Report

Merging #1686 into master will decrease coverage by 0.22%.
The diff coverage is 78.26%.

@@            Coverage Diff             @@
##           master    #1686      +/-   ##
==========================================
- Coverage   61.86%   61.63%   -0.23%     
==========================================
  Files         116      119       +3     
  Lines        8731     8810      +79     
==========================================
+ Hits         5401     5430      +29     
- Misses       2926     2973      +47     
- Partials      404      407       +3

Impacted Files	Coverage Δ
pkg/distributor/distributor.go	75% <66.66%> (+6.08%)	⬆️
pkg/util/flagext/bytesize.go	77.77% <77.77%> (ø)
pkg/distributor/validator.go	81.81% <81.81%> (ø)
pkg/promtail/targets/tailer.go	73.56% <0%> (-2.3%)	⬇️
pkg/promtail/targets/filetarget.go	68.71% <0%> (-1.85%)	⬇️
pkg/ingester/transfer.go	65% <0%> (-1.43%)	⬇️
pkg/logql/evaluator.go	91.63% <0%> (-0.65%)	⬇️
pkg/util/flagext/labelset.go	0% <0%> (ø)
... and 1 more

[cyriltovena]

LGTM.

Although I like using KB/MB I would be careful mixin unit across our full configuration. Do you support also 10000 as bytes without units ? If yes this is nice and you should add a test.

[owen-d]

ByteSize parses bytes by default if you don't pass a duration. The actual issue with transparently moving all our configs to the new ByteSize type is that many config arguments are suffixed in an unfortunate way like distributor.ingestion-rate-limit-mb. It wouldn't really make much sense for that to suddenly default to bytes and take other units.