accept gzip encoding

[dmarzzz]

📝 Summary

From a discussion with @zeroecco on how to lower bandwidth on the blocknative relay we came to the idea that we could utilize well known compression like gzip, but only if requests coming from mev-boost specified that.

Minimum transmittable unit is 1500 Bytes total w/ 1250 Bytes realistically usable and a block is around ~12KB, gzip will compress ~60% to ~6Kb which would be a packet reduction from 10 to 5 for the total packet train. This also reduces time to last packet and bandwidth, which could be 1 - 5ms based on response time at this size.

If a system doesn't have this enabled the content-encoding will simply be ignored. On top of that, this improvement will really only be visible for GetPayload response.

To benefit from this in your relay or other components make sure you configure your reverse proxy [HA Proxy, NGINX, etc] to support gzip!

⛱ Motivation and Context

I want to go fast

📚 References

https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Content-Encoding

https://www.rfc-editor.org/rfc/rfc2616#section-3.5

✅ I have run these commands

• [x] make lint
• [x] make test-race
• [x] go mod tidy

[codecov-commenter]

Codecov Report

Merging #365 (1939207) into main (496bf59) will increase coverage by 0.47%. The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main     #365      +/-   ##
==========================================
+ Coverage   80.94%   81.41%   +0.47%     
==========================================
  Files           5        5              
  Lines         677      678       +1     
==========================================
+ Hits          548      552       +4     
+ Misses         99       97       -2     
+ Partials       30       29       -1     

Flag	Coverage Δ
unittests	81.41% <100.00%> (+0.47%)	:arrow_up:

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
server/utils.go	72.85% <100.00%> (+0.39%)	:arrow_up:
server/service.go	79.15% <0.00%> (+0.74%)	:arrow_up:

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[metachris]

Could you add a little bit of context please?

[zeroecco]

Internally our testing of the [edit] math on whether this would work or not[end edit] did show a time to last packet reduction in deliveries of blocks of roughly 1-5ms depending on the resources of the validator.

Additionally this change can lead to more time for validators to propose on chain and thereby potentially lead fewer missing proposals though more efficient packet transport over the wider internet.

[dmarzzz]

added some more context @metachris , didn't realize drafts showed up in public repos whoops!

[metachris]

Thanks. It seems gzip would automatically be decoded, but deflate not?

[metachris]

Very cool feature btw and just 1 line of code with significant impact. I strongly support this.

[dmarzzz]

Awesome good fix! I added a note to the PR as well that for relays and others to enable this make sure you configure your reverse proxy [HA Proxy, NGINX, etc] to support gzip!

[dmarzzz]

The test that lint is tripping up passes for me locally 🤔

[metachris]

Failing lint step fixed in https://github.com/flashbots/mev-boost/pull/374

[metachris]

@dmarzzz could you add a test where the mockserver returns a gzipped response?

[metachris]

Added a test for the gzip response: https://github.com/dmarzzz/mev-boost/pull/1 (needs to be merged by @dmarzzz into his repo to update this PR)

[dmarzzz]

@metachris thanks appreciate it, wasn't able to get to it till this weekend. When I merged it auto dismissed @jtraglia review