add isFeeder query

Author: colmazia

proto/feeds/v1beta1/query.proto

@@ -57,10 +57,15 @@ service Query {
     option (google.api.http).get = "/feeds/v1beta1/delegators/{delegator}/signals";
   }
 
-  // SupportedFeeds is a RPC method that return list of currect supported feeds
+  // SupportedFeeds is a RPC method that returns list of currect supported feeds
   rpc SupportedFeeds(QuerySupportedFeedsRequest) returns (QuerySupportedFeedsResponse) {
     option (google.api.http).get = "/feeds/v1beta1/supported-feeds";
   }
+
+  // IsFeeder is a RPC method that returns whether an account is a feeder for specified validator.
+  rpc IsFeeder(QueryIsFeederRequest) returns (QueryIsFeederResponse) {
+    option (google.api.http).get = "/feeds/v1beta1/feeder/{validator_address}/{feeder_address}";
+  }
 }
 
 // QueryPricesRequest is the request type for the Query/Prices RPC method.
@@ -187,3 +192,17 @@ message QuerySupportedFeedsResponse {
   // SupportedFeeds is a list of currently supported feeds, and its last update time and block.
   SupportedFeeds supported_feeds = 1 [(gogoproto.nullable) = false];
 }
+
+// QueryIsFeederRequest is request type for the Query/IsFeeder RPC method.
+message QueryIsFeederRequest {
+  // ValidatorAddress is a validator address
+  string validator_address = 1;
+  // FeederAddress is a candidate account
+  string feeder_address = 2;
+}
+
+// QueryIsFeederResponse is response type for the Query/IsFeeder RPC method.
+message QueryIsFeederResponse {
+  // IsFeeder is true if this account has been granted by validator
+  bool is_feeder = 1;
+}

x/feeds/keeper/grpc_query.go

@@ -254,3 +254,20 @@ func (q queryServer) Params(c context.Context, _ *types.QueryParamsRequest) (*ty
 		Params: q.keeper.GetParams(ctx),
 	}, nil
 }
+
+// IsFeeder queries grant of account on this validator
+func (q queryServer) IsFeeder(
+	c context.Context,
+	req *types.QueryIsFeederRequest,
+) (*types.QueryIsFeederResponse, error) {
+	ctx := sdk.UnwrapSDKContext(c)
+	val, err := sdk.ValAddressFromBech32(req.ValidatorAddress)
+	if err != nil {
+		return nil, err
+	}
+	rep, err := sdk.AccAddressFromBech32(req.FeederAddress)
+	if err != nil {
+		return nil, err
+	}
+	return &types.QueryIsFeederResponse{IsFeeder: q.keeper.IsFeeder(ctx, val, rep)}, nil
+}

x/feeds/keeper/keeper.go

@@ -16,6 +16,7 @@ type Keeper struct {
 	cdc           codec.BinaryCodec
 	oracleKeeper  types.OracleKeeper
 	stakingKeeper types.StakingKeeper
+	authzKeeper   types.AuthzKeeper
 
 	authority string
 }
@@ -56,3 +57,14 @@ func (k Keeper) IsBondedValidator(ctx sdk.Context, addr sdk.ValAddress) bool {
 
 	return val.IsBonded()
 }
+
+// IsFeeder checks if the validator granted to the feeder
+func (k Keeper) IsFeeder(ctx sdk.Context, validator sdk.ValAddress, feeder sdk.AccAddress) bool {
+	cap, _ := k.authzKeeper.GetAuthorization(
+		ctx,
+		feeder,
+		sdk.AccAddress(validator),
+		sdk.MsgTypeURL(&types.MsgSubmitPrices{}),
+	)
+	return cap != nil
+}

x/feeds/types/expected_keepers.go

@@ -5,6 +5,7 @@ import (
 
 	"cosmossdk.io/math"
 	sdk "github.com/cosmos/cosmos-sdk/types"
+	"github.com/cosmos/cosmos-sdk/x/authz"
 	stakingtypes "github.com/cosmos/cosmos-sdk/x/staking/types"
 
 	oracletypes "github.com/bandprotocol/chain/v2/x/oracle/types"
@@ -30,3 +31,13 @@ type StakingKeeper interface {
 		valAddr sdk.ValAddress,
 	) (delegation stakingtypes.Delegation, found bool)
 }
+
+// AuthzKeeper defines the expected authz keeper. for query and testing only don't use to create/remove grant on deliver tx
+type AuthzKeeper interface {
+	GetAuthorization(
+		ctx sdk.Context,
+		grantee sdk.AccAddress,
+		granter sdk.AccAddress,
+		msgType string,
+	) (authz.Authorization, *time.Time)
+}