Cosmos-sdk: Add support for query parameters on staking queriers

[fedekunze]

Summary

Add support for query parameters on staking queriers for Gaia-lite GET requests

Problem Definition

No current way to query staking parameters from validators or delegation txs.

Rephrasing @sunnya97 https://github.com/cosmos/cosmos-sdk/pull/2139#discussion_r213881407:

It'd be nice for staking queriers to support query parameters so you can query specifically bonded, jailed, etc

Same applies for the state of delegations, unbonds and redelegations on a specific block height, which is currently supported on CLI

Proposal

Delegation txs:

For the following endpoints:

• delegator summary (delegators/{delegatorAddr})
• .../<delegations>/...
• .../unbonding-delegations/...
• .../redelegations/...

Queries supported:

• ?height=<block_height>: status at a specific block height.

Examples:

GET /stake/delegators/{delegatorAddr}?height=<block_height>
GET /stake/delegators/{delegatorAddr}/delegations/{validatorAddr}?height=<block_height>
GET /stake/delegators/{delegatorAddr}/unbonding-delegations/{validatorAddr}?height=<block_height>

Validators query

For the following endpoints:

• .../validators:

Queries supported:

• ?jailed=<true/false>
• ?status=<bonded/unbonding/unbonded>
• ?height=<block_height>: status at a specific block height. Useful to track voting power progress
• ?moniker=<name>
• ?website=<website>

Examples:

GET /stake/delegators/{delegatorAddr}/validators?jailed=true&status=unbonded
GET /stake/validators?height=32213

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For Admin Use

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[cwgoes]

Concept ACK.

Some of these are efficient and others are not - retrieving bonded validators, for example, is easy - but we aren't going to add an index from monikers or websites to validator addresses, so those queries would require O(n) iteration.

[faboweb]

What is the benefit of querying for jailed or status?
I also don't think splitting the delegation summary provides a huge benefit. An application will probably always want to query all of them.

[cwgoes]

@fedekunze Can this be closed?

[fedekunze]

@cwgoes I don't think so. We can label it pre1.0 if you want, not high priority but definitely a nice to have

[cwgoes]

cc @alessio

[jackzampolin]

Is this still something we want @fedekunze?

[fedekunze]

I think so, yes. Would it be possible to set the context to a specific height i.e ctx = ctx.WithBlockHeight(height) and then do the query as usual ? cc @alexanderbez @rigelrozanski

[alexanderbez]

I've already implemented supporting height queries for querier-based queries (wow) here. Does this accomplish your needs?

[fedekunze]

cool ! do we need to add REST query params or it only supports CLI for the moment ?

[alexanderbez]

Only CLI atm because it was super trivial. REST will involve more work. Essentially each REST handler will have to parse for a height query param and update the context. Still trivial and easy to implement, just more places in the code to this.

cc @aayushijain23

[jackzampolin]

Closing as implemented.