RPC-like function and service mapper

• Optimized for use in RPC scenarios
• Registration of service methods and plain functions
• Supports (optional) context argument to functions and methods
• Call functions by name, call service methods by scoped name (Service.Method) or by method name only
• Supports several function/method signatures (see below)
• Method name mapper and registered methods filtering
• stdlib-only dependencies

Supported function/method signatures

func() error
func() (outputType, error)
func(inputType) error
func(inputType) (outputType, error)
func(contextType, inputType) error
func(contextType, inputType) (outputType, error)

When registering a service, methods with signatures which do not match to any of the above are skipped.

Examples

Service registration

type MyService struct {}

type testInput struct {
    Foo string
}

function testOutput struct {
    Greeting string
}

// rpcmap will find this method on registration
func (s *MyService) Hello(i *testInput) (*testOutput, error) {
    return &testOutput{ Greeting: fmt.Sprintf("Hi,%s!", i.Foo) }, nil
}
    
mapper := rpcmap.New()

mapper.Service(&MyService{}) // register service

mapper.Func("f3", func(i int) (string, error) { // register function
        return fmt.Sprintf("Hi,%d", i), nil
})

// Call service method with dotted notation. Note that the method name is lowercase when default mapper is used.
// To call service methods by method name only, register service with DefaultService().
rv1, err := mapper.CallMethod("S.hello", nil, &testInput{ Foo: "zz"})
fmt.Printf("rv.greeting = %s", rv.(*testOutput).Greeting)

// Call function
rv2, err := mapper.CallFunc("f3", nil, 123)


// typical RPC case (error handling omitted for simplicity)
meth := mapper.GetCallable(methodName)
arg := meth.MakeArg() // if function has no args, returns Ptr to empty struct instance
json.Unmarshal(data, arg)
rv, err := meth->Call(myContext, arg) // If method signature has no context argument, it will be ignored. 
if nil != err {
    result,_ = json.Marshal(rv)
}

For more information, see Documentation

License

MIT.