feat: add debug storage export endpoint

[kolesnikovae]

The PR is aimed at improving debuggability. In order to solve issues like #715 more efficiently we need an option to export data from the storage in a user-friendly way. We extend our /debug endpoints list with /debug/storage/export/{db} that exports values from the storage via HTTP.

Example:

curl -G -o /tmp/segment --data-urlencode "k=s:pyroscope.server.cpu{}" http://localhost:4040/debug/storage/export/segments

The request will write s:pyroscope.server.cpu{} segment raw bytes to /tmp/segment.

NOTE: We have set 15 seconds HTTP server timeout, and it is not configurable. I'm wondering if this should be lifted - say, a minute, or two.

[github-actions]

size-limit report 📦

Path	Size	Loading time (3g)	Running time (snapdragon)	Total time
webapp/public/assets/app.js	350.25 KB (0%)	7.1 s (0%)	1.1 s (+3.71% 🔺)	8.1 s

[pyroscopebot]

Screenshots

Throughput

Disk Usage

Memory

Upload Errors (Total)

Successful Uploads (Total)

CPU Utilization

Result

	main	pr	diff	threshold
throughput	183.62	169.68	🟥 -13.94 (-7.89%)	5%
total items processed	54991.00	50741.00	🟥 -4250.00 (-8.04%)	5%

Details

Name	Description	Query for main	Query for pr
throughput		rate(pyroscope_http_request_duration_seconds_count{handler="/ingest", instance="pyroscope-main:4040"}[5m])	rate(pyroscope_http_request_duration_seconds_count{handler="/ingest", instance="pyroscope:4040"}[5m])
total items processed		pyroscope_http_request_duration_seconds_count{handler="/ingest", instance="pyroscope-main:4040"}	pyroscope_http_request_duration_seconds_count{handler="/ingest", instance="pyroscope:4040"}

Generated by 🚫 dangerJS against 126b70c

[codecov]

Codecov Report

Merging #752 (eb546a7) into main (97ca0f4) will decrease coverage by 0.62%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##             main     #752      +/-   ##
==========================================
- Coverage   76.09%   75.48%   -0.61%     
==========================================
  Files          60       61       +1     
  Lines        2070     2112      +42     
  Branches      431      444      +13     
==========================================
+ Hits         1575     1594      +19     
- Misses        465      488      +23     
  Partials       30       30              

Impacted Files	Coverage Δ
...mponents/FlameGraph/FlameGraphComponent/Header.tsx	67.45% <0.00%> (-23.03%)	⬇️
...components/FlameGraph/FlameGraphComponent/color.ts	78.13% <0.00%> (-16.42%)	⬇️
...lameGraph/FlameGraphComponent/Flamegraph_render.ts	96.86% <0.00%> (-0.09%)	⬇️
...nts/FlameGraph/FlameGraphComponent/colorPalette.ts	100.00% <0.00%> (ø)
...nents/FlameGraph/FlameGraphComponent/Flamegraph.ts	93.75% <0.00%> (+0.04%)	⬆️
...ents/FlameGraph/FlameGraphComponent/DiffLegend.tsx	89.48% <0.00%> (+0.29%)	⬆️
...omponents/FlameGraph/FlameGraphComponent/index.tsx	85.00% <0.00%> (+0.96%)	⬆️

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