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msg_service_router: reduce code complexity #7570

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merged 4 commits into from
Oct 16, 2020
Merged

msg_service_router: reduce code complexity #7570

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9db20b4
msg_service_router: reduce code complexity
robert-zaremba Oct 15, 2020
1294fad
order imports
robert-zaremba Oct 15, 2020
40bf3c9
Merge branch 'master' into robert/router-update
Oct 16, 2020
f7d6a8e
Merge branch 'master' into robert/router-update
mergify[bot] Oct 16, 2020
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29 changes: 16 additions & 13 deletions baseapp/msg_service_router.go
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Original file line number Diff line number Diff line change
Expand Up @@ -4,13 +4,13 @@ import (
"context"
"fmt"

"github.com/gogo/protobuf/proto"

gogogrpc "github.com/gogo/protobuf/grpc"
"github.com/gogo/protobuf/proto"
"google.golang.org/grpc"

codectypes "github.com/cosmos/cosmos-sdk/codec/types"
sdk "github.com/cosmos/cosmos-sdk/types"
sdkerrors "github.com/cosmos/cosmos-sdk/types/errors"
)

// MsgServiceRouter routes fully-qualified Msg service methods to their handler.
Expand Down Expand Up @@ -59,28 +59,24 @@ func (msr *MsgServiceRouter) RegisterService(sd *grpc.ServiceDesc, handler inter

msr.interfaceRegistry.RegisterCustomTypeURL((*sdk.MsgRequest)(nil), fqMethod, msg)
return nil
}, func(ctx context.Context, req interface{}, info *grpc.UnaryServerInfo, handler grpc.UnaryHandler) (resp interface{}, err error) {
return nil, nil
})
}, noopInterceptor)

msr.routes[fqMethod] = func(ctx sdk.Context, req sdk.MsgRequest) (*sdk.Result, error) {
ctx = ctx.WithEventManager(sdk.NewEventManager())

// Call the method handler from the service description with the handler object.
res, err := methodHandler(handler, sdk.WrapSDKContext(ctx), func(_ interface{}) error {
// We don't do any decoding here because the decoding was already done.
return nil
}, func(goCtx context.Context, _ interface{}, _ *grpc.UnaryServerInfo, handler grpc.UnaryHandler) (interface{}, error) {
interceptor := func(goCtx context.Context, _ interface{}, _ *grpc.UnaryServerInfo, handler grpc.UnaryHandler) (interface{}, error) {
goCtx = context.WithValue(goCtx, sdk.SdkContextKey, ctx)
return handler(goCtx, req)
})
}
// Call the method handler from the service description with the handler object.
// We don't do any decoding here because the decoding was already done.
res, err := methodHandler(handler, sdk.WrapSDKContext(ctx), noopDecoder, interceptor)
if err != nil {
return nil, err
}

resMsg, ok := res.(proto.Message)
if !ok {
return nil, fmt.Errorf("can't proto encode %T", resMsg)
return nil, sdkerrors.Wrapf(sdkerrors.ErrInvalidType, "Expecting proto.Message, got %T", resMsg)
}

return sdk.WrapServiceResult(ctx, resMsg, err)
Expand All @@ -92,3 +88,10 @@ func (msr *MsgServiceRouter) RegisterService(sd *grpc.ServiceDesc, handler inter
func (msr *MsgServiceRouter) SetInterfaceRegistry(interfaceRegistry codectypes.InterfaceRegistry) {
msr.interfaceRegistry = interfaceRegistry
}

// gRPC NOOP interceptor
func noopInterceptor(_ context.Context, _ interface{}, _ *grpc.UnaryServerInfo, _ grpc.UnaryHandler) (interface{}, error) {
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Are you planning to use this function elsewhere? What's the benefit of extracting a tiny snippet of code that just return nil, nil when it's not yet reused anywhere else?

This smells like early refactoring, and as such, pointless (best case scenario) if not potentially harmful.

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Please check the PR description.

Are you planning to use this function elsewhere?

The function is private

What's the benefit of extracting a tiny snippet of code

improving readability

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@alessio alessio Oct 16, 2020 •
edited
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Does it really improve readability to extract an empty function? I too tend to prefer named functions, though it generally boils down to one question to me: Am I going to use this function elsewhere?

If I am, then it's a no-brainer and I would define it as a separate function right away. If not well, does the benefit overweight the cost of increasing file size and polluting the private namespace?

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Good questions. In fact, sometimes it's opposite - extracting a function it can even reduce the compiled code, because we don't need to carry the context. So depending on the compiler.

Again - function is private, and it's used. Going further with your argument we would prefer to have big functions, which, IMHO is not good.

So, I don't see any benefit. I would see some if the parent function would be smaller and less nested.

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Suggested change
func noopInterceptor(_ context.Context, _ interface{}, _ *grpc.UnaryServerInfo, _ grpc.UnaryHandler) (interface{}, error) {
func noopInterceptor(_ interface{}, _ interface{}, _ interface{}, _ interface{}) (interface{}, error) {

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I think this would work too

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true, though I prefer seeing the exact signature from gogogrpc

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exactly, no need to generalize here.

return nil, nil
}

func noopDecoder(_ interface{}) error { return nil }