x/params: query gRPC service (#6585)

* Add grpc queries in x/params

* Modify grpc query tests format

* Modify query request and revert changes in querier

* Fix protobuf lint issues

proto/cosmos/params/query.proto

@@ -0,0 +1,25 @@
+syntax = "proto3";
+package cosmos.params;
+
+import "gogoproto/gogo.proto";
+import "cosmos/params/params.proto";
+
+option go_package = "github.com/cosmos/cosmos-sdk/x/params/types/proposal";
+
+// Query creates service with Parameters as rpc
+service Query{
+    // Parameters queries all params
+    rpc Parameters (QueryParametersRequest) returns (QueryParametersResponse) {}
+}
+
+// QueryParametersRequest is request type for the Query/Parameters RPC method
+message QueryParametersRequest{
+    string subspace = 1;
+
+    string key = 2;
+}
+
+// QueryParametersResponse is response type for the Query/Parameters RPC method
+message QueryParametersResponse{
+    cosmos.params.ParamChange params = 1 [(gogoproto.nullable) = false];
+} 

x/params/keeper/grpc_query.go

@@ -0,0 +1,36 @@
+package keeper
+
+import (
+	"context"
+
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/status"
+
+	sdk "github.com/cosmos/cosmos-sdk/types"
+	sdkerrors "github.com/cosmos/cosmos-sdk/types/errors"
+	"github.com/cosmos/cosmos-sdk/x/params/types/proposal"
+)
+
+var _ proposal.QueryServer = Keeper{}
+
+// Parameters returns subspace params
+func (k Keeper) Parameters(c context.Context, req *proposal.QueryParametersRequest) (*proposal.QueryParametersResponse, error) {
+	if req == nil {
+		return nil, status.Errorf(codes.InvalidArgument, "empty request")
+	}
+
+	if req.Subspace == "" || req.Key == "" {
+		return nil, status.Errorf(codes.InvalidArgument, "invalid request")
+	}
+
+	ss, ok := k.GetSubspace(req.Subspace)
+	if !ok {
+		return nil, sdkerrors.Wrap(proposal.ErrUnknownSubspace, req.Subspace)
+	}
+
+	ctx := sdk.UnwrapSDKContext(c)
+	rawValue := ss.GetRaw(ctx, []byte(req.Key))
+	params := proposal.NewParamChange(req.Subspace, req.Key, string(rawValue))
+
+	return &proposal.QueryParametersResponse{Params: params}, nil
+}

x/params/keeper/grpc_query_test.go

@@ -0,0 +1,86 @@
+package keeper_test
+
+import (
+	"fmt"
+
+	sdk "github.com/cosmos/cosmos-sdk/types"
+	"github.com/cosmos/cosmos-sdk/x/params/types"
+	"github.com/cosmos/cosmos-sdk/x/params/types/proposal"
+)
+
+func (suite *KeeperTestSuite) TestGRPCQueryParams() {
+	var (
+		req      *proposal.QueryParametersRequest
+		expValue string
+		space    types.Subspace
+	)
+	key := []byte("key")
+
+	testCases := []struct {
+		msg      string
+		malleate func()
+		expPass  bool
+	}{
+		{
+			"empty request",
+			func() {
+				req = &proposal.QueryParametersRequest{}
+			},
+			false,
+		},
+		{
+			"invalid request with subspace not found",
+			func() {
+				req = &proposal.QueryParametersRequest{Subspace: "test"}
+			},
+			false,
+		},
+		{
+			"invalid request with subspace and key not found",
+			func() {
+				req = &proposal.QueryParametersRequest{Subspace: "test", Key: "key"}
+			},
+			false,
+		},
+		{
+			"success",
+			func() {
+				space = suite.app.ParamsKeeper.Subspace("test").
+					WithKeyTable(types.NewKeyTable(types.NewParamSetPair(key, paramJSON{}, validateNoOp)))
+				req = &proposal.QueryParametersRequest{Subspace: "test", Key: "key"}
+				expValue = ""
+			},
+			true,
+		},
+		{
+			"update value success",
+			func() {
+				err := space.Update(suite.ctx, key, []byte(`{"param1":"10241024"}`))
+				suite.Require().NoError(err)
+				req = &proposal.QueryParametersRequest{Subspace: "test", Key: "key"}
+				expValue = `{"param1":"10241024"}`
+			},
+			true,
+		},
+	}
+
+	suite.SetupTest()
+	ctx := sdk.WrapSDKContext(suite.ctx)
+
+	for _, tc := range testCases {
+		suite.Run(fmt.Sprintf("Case %s", tc.msg), func() {
+			tc.malleate()
+
+			res, err := suite.queryClient.Parameters(ctx, req)
+
+			if tc.expPass {
+				suite.Require().NoError(err)
+				suite.Require().NotNil(res)
+				suite.Require().Equal(expValue, res.Params.Value)
+			} else {
+				suite.Require().Error(err)
+				suite.Require().Nil(res)
+			}
+		})
+	}
+}

x/params/keeper/keeper_test.go

@@ -5,12 +5,46 @@ import (
 	"testing"
 
 	"github.com/stretchr/testify/require"
+	"github.com/stretchr/testify/suite"
+	abci "github.com/tendermint/tendermint/abci/types"
 
+	"github.com/cosmos/cosmos-sdk/baseapp"
+	"github.com/cosmos/cosmos-sdk/simapp"
 	"github.com/cosmos/cosmos-sdk/store/prefix"
 	sdk "github.com/cosmos/cosmos-sdk/types"
 	"github.com/cosmos/cosmos-sdk/x/params/types"
+	"github.com/cosmos/cosmos-sdk/x/params/types/proposal"
 )
 
+type KeeperTestSuite struct {
+	suite.Suite
+
+	app *simapp.SimApp
+	ctx sdk.Context
+
+	queryClient proposal.QueryClient
+}
+
+func (suite *KeeperTestSuite) SetupTest() {
+	suite.app, suite.ctx = createTestApp(true)
+
+	queryHelper := baseapp.NewQueryServerTestHelper(suite.ctx, suite.app.InterfaceRegistry())
+	proposal.RegisterQueryServer(queryHelper, suite.app.ParamsKeeper)
+	suite.queryClient = proposal.NewQueryClient(queryHelper)
+}
+
+func TestKeeperTestSuite(t *testing.T) {
+	suite.Run(t, new(KeeperTestSuite))
+}
+
+// returns context and app
+func createTestApp(isCheckTx bool) (*simapp.SimApp, sdk.Context) {
+	app := simapp.Setup(isCheckTx)
+	ctx := app.BaseApp.NewContext(isCheckTx, abci.Header{})
+
+	return app, ctx
+}
+
 func validateNoOp(_ interface{}) error { return nil }
 
 func TestKeeper(t *testing.T) {

x/params/types/proposal/proposal.go

@@ -100,3 +100,11 @@ func ValidateChanges(changes []ParamChange) error {
 
 	return nil
 }
+
+// NewQueryParametersRequest returns the new instance of QueryParametersRequest
+func NewQueryParametersRequest(ss, key string) *QueryParametersRequest {
+	return &QueryParametersRequest{
+		Subspace: ss,
+		Key:      key,
+	}
+}