R4R: Add tx/encode endpoint and CLI command

[ducembarr]

This PR adds a /tx/encode endpoint to Gaia to take a JSON-ified transaction, serialize it using the Amino wire format, and return the serialized bytes encoded to a base64 string. The wire format is necessary to determine a transaction's hash, so it's useful for client applications that want to build their own transactions without being dependent on wire serialization changes. I've also included an equivalent gaiacli tx encode command.

• Targeted PR against correct branch (see CONTRIBUTING.md)

• Linked to github-issue with discussion and accepted design OR link to spec that describes this work.

  • N/A: Discussed the feature with the Cosmos devs in Slack

• Wrote tests

• Updated relevant documentation (docs/)

• Added entries in PENDING.md with issue #

• rereviewed Files changed in the github PR explorer

---

For Admin Use:

• Added appropriate labels to PR (ex. wip, ready-for-review, docs)
• Reviewers Assigned
• Squashed all commits, uses message "Merge pull request #XYZ: [title]" (coding standards)

[jackzampolin]

This also might be interesting as a microservice...

[alessio]

Both this and the rest endpoint should live under the x/auth package. The same applies to the broadcast command/endpoint too, though I reckon we can get this in as it is since such refactoring would be out of context of the PR. /cc @jackzampolin @cwgoes @alexanderbez

[alexanderbez]

Yes, both should be moved to the auth module. Preferably in this PR.

[ducembarr]

Cool, I've moved both to the auth module.

[alessio]

ACK'd

[jackzampolin]

After a significant discussion offline with the SDK team, I don't think this is something we want to have added. cc @cwgoes

[ducembarr]

@jackzampolin could you provide a bit more detail on why? Thanks!

[alexanderbez]

@ducembarr we deem that such functionality should not exist in the SDK as it's something we do not intend on maintaining. I believe it would be a great addition as a microservice elsewhere or part of a wallet or block explorer.

[jackzampolin]

After a longer discussion this endpoint does have significant utility for users who need to push high volumes of transactions and is a good stopgap until we have amino implementations in other languages

[codecov]

Codecov Report

Merging #3523 into develop will decrease coverage by 0.02%.
The diff coverage is 36.36%.

@@             Coverage Diff             @@
##           develop    #3523      +/-   ##
===========================================
- Coverage    57.12%   57.09%   -0.03%     
===========================================
  Files          190      191       +1     
  Lines        14956    14967      +11     
===========================================
+ Hits          8544     8546       +2     
- Misses        5872     5877       +5     
- Partials       540      544       +4

[alexanderbez]

Is this from a copy pasta?

[ducembarr]

ICS20 seemed the most reasonable since it's related to creating and broadcasting transactions.

[alexanderbez]

Yes, both should be moved to the auth module. Preferably in this PR.

[alessio]

few changes are required

[cwgoes]

Ref #3560, which can be separate from this PR, but we should definitely do this.

[ducembarr]

@alessio @alexanderbez I've responded to PR comments; please re-review. Thanks!

[zhiyuzhang86]

👍 💯