change(log): Log a cute message for blocks that were mined by Zebra (off by default)

[teor2345]

Motivation

It's nice to see when Zebra has mined some blocks:

2023-02-03T05:52:06.475443Z INFO zebra_state::service::write: looks like this block was mined by Zebra! text="z🦓" data="7af09fa693" height=2215022 hash=00531335a993d94aed848c76cceba5274e2913b14a286d6a485b44444eb3a9d6
2023-02-03T05:52:06.475598Z INFO zebra_rpc::methods::get_block_template_rpcs: submit block accepted block_hash=block::Hash("00531335a993d94aed848c76cceba5274e2913b14a286d6a485b44444eb3a9d6") block_height="2215022"

This is part of #5934, testing v5 transactions, extra coinbase data, and other minor changes allowed by the consensus rules or RPCs.

Specifications

Coinbase transactions can contain up to 100 bytes of data, but the consensus rules only specify the first 1-6 bytes.

Solution

• Mark Zebra coinbase transactions with extra coinbase data if like_zcashd is false or if specifically configured
  • Make debug_like_zcashd into a config rather than a constant
  • Make a config for extra_coinbase_data
• Log when we commit a block mined by Zebra to our state
  • Don't log control characters
  • Rate-limit to 1 in 1000 blocks

Related changes:

• Reduce logging instrumentation during block writes
• Add network and commit to write task logs

Review

This is a low-priority review.

Reviewer Checklist

• Will the PR name make sense to users?
  • Does it need extra CHANGELOG info? (new features, breaking changes, large changes)
• Are the PR labels correct?
• Does the code do what the ticket and PR says?
  • Does it change concurrent code, unsafe code, or consensus rules?
• How do you know it works? Does it have tests?

[teor2345]

When I mine a block with this PR, here is what zebrad logs:

And when it is loading blocks mined by other zebrads:

[codecov]

Codecov Report

Merging #6098 (f85673c) into main (6adf2b5) will increase coverage by 0.03%.
The diff coverage is 66.66%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #6098      +/-   ##
==========================================
+ Coverage   77.98%   78.02%   +0.03%     
==========================================
  Files         304      304              
  Lines       39087    39185      +98     
==========================================
+ Hits        30482    30574      +92     
- Misses       8605     8611       +6     

[arya2]

This looks great! Thank you for adding this, it's nice to see Zebra committing blocks that were mined with Zebra.

[teor2345]

Thanks for the review, I'll do the metrics in a follow-up PR.

[upbqdn]

Looks great, I left a few minor suggestions.

I also noticed this comment https://github.com/zcashfoundation/zebra/blob/f85673c9aa8794efff68f34741afe49abebce5c0/zebra-chain/src/transparent/serialize.rs#L184 says the "The height may produce 0..=5 initial bytes of coinbase data.", which was confusing since the consensus rules say "The length of heightBytes MUST be in the range {1 .. 5}." Should we refactor that comment?

[teor2345]

Follow-ups:

Consensus rule comment mistake:

• should be 1..=6 initial bytes of coinbase data, small heights are 1, other heights are heightBytes + 1
• change(log): Log a cute message for blocks that were mined by Zebra (off by default) #6098 (review)

Optional:

• metrics for the number of likely Zebra blocks:
  • change(log): Log a cute message for blocks that were mined by Zebra (off by default) #6098 (comment)
• put a constant inline in a format string:
  • change(log): Log a cute message for blocks that were mined by Zebra (off by default) #6098 (comment)
• comment grammar:
  • change(log): Log a cute message for blocks that were mined by Zebra (off by default) #6098 (comment)
  • change(log): Log a cute message for blocks that were mined by Zebra (off by default) #6098 (comment)