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x/evidence

The x/evidence module is responsible for handling multi-asset coin transfers between accounts and tracking special-case pseudo-transfers which must work differently with particular kinds of accounts.

Usage

Import the module.

import (
   "github.com/cosmos/cosmos-sdk/x/evidence"
   evidencekeeper "github.com/cosmos/cosmos-sdk/x/evidence/keeper"
   evidencetypes "github.com/cosmos/cosmos-sdk/x/evidence/types"
)

Add AppModuleBasic to your ModuleBasics.

var (
  ModuleBasics = module.NewBasicManager(
    // ...
    evidence.AppModuleBasic{},
  }
)

Add the evidence keeper to your apps struct.

  type app struct {
    // ...
    EvidenceKeeper   evidencekeeper.Keeper
    // ...
  }

Add the evidence store key to the group of store keys.

func NewApp(...) *App {
  // ...
   keys := sdk.NewKVStoreKeys(
   evidencetypes.StoreKey, 
   )
  // ...
}

Create the keeper. Note, the x/evidence module depends on the x/staking and x/slashing modules. Evidence has expected interfaces, these interfaces are linked to slashing and staking. You can find these interfaces here

func NewApp(...) *App {
   // ...
   // create evidence keeper with router
   evidenceKeeper := evidencekeeper.NewKeeper(
     appCodec, keys[evidencetypes.StoreKey], &app.StakingKeeper, app.SlashingKeeper,
   )
}

Add the x/evidence module to the app's ModuleManager.

func NewApp(...) *App {
  // ...
  app.mm = module.NewManager(
    // ...
    evidence.NewAppModule(app.EvidenceKeeper),
    // ...
  )
}

Set the x/evidence module begin blocker order.

func NewApp(...) *App {
 // ...
  app.mm.SetOrderBeginBlockers(
    // ...
    evidencetypes.ModuleName, 
    // ...
  )
}

Set the x/evidence module genesis order.

func NewApp(...) *App {
  // ...
  app.mm.SetOrderInitGenesis(..., evidencetypes.ModuleName, ...)
}

Add the x/evidence module to the simulation manager (if you have one set).

func NewApp(...) *App {
  // ...
  app.sm = module.NewSimulationManager(
    // ...
    evidence.NewAppModule(app.EvidenceKeeper),
    // ...
  )
}

Genesis

The x/evidence module defines its genesis state as follows:

type GenesisState struct {
 // evidence defines all the evidence at genesis.
 Evidence []*types.Any `protobuf:"bytes,1,rep,name=evidence,proto3" json:"evidence,omitempty"`
}

Messages

View supported messages at docs.cosmos.network/v0.40/modules/evidence

Client

Evidence supports querying of old evidence and submission of new evidence. There are two queries. One for all the evidence, and one for a specific piece of evidence.

CLI

The evidence module supports the blow command to query evidence.

Usage:
  app query evidence [flags]

Flags:
      --count-total       count total number of records in evidence to query for
      --height int        Use a specific height to query state at (this can error if the node is pruning state)
  -h, --help              help for evidence
      --limit uint        pagination limit of evidence to query for (default 100)
      --node string       <host>:<port> to Tendermint RPC interface for this chain (default "tcp://localhost:26657")
      --offset uint       pagination offset of evidence to query for
  -o, --output string     Output format (text|json) (default "text")
      --page uint         pagination page of evidence to query for. This sets offset to a multiple of limit (default 1)
      --page-key string   pagination page-key of evidence to query for

REST

Evidence REST API supports only queries of evidence. To submit evidence please use gRPC or the cli.

gRPC

Evidence supports both querying and submitting transactions via gRPC

Query

gRPC query

Tx

gRPC Tx