feat(core): add ADR 033 (inter-module communication) Client interface

core/intermodule/client.go

@@ -0,0 +1,32 @@
+package intermodule
+
+import (
+	"context"
+
+	"google.golang.org/grpc"
+)
+
+// Client is an inter-module client as specified in ADR-033. It
+// allows one module to send msg's and queries to other modules provided
+// that the request is valid and can be properly authenticated.
+type Client interface {
+	grpc.ClientConnInterface
+
+	// InvokerByMethod resolves an invoker for the provided method or returns an error.
+	InvokerByMethod(method string) (Invoker, error)
+
+	// InvokerByRequest resolves an invoker for the provided request type or returns an error.
+	// This only works for Msg's as they are routed based on type name in transactions already.
+	// For queries use InvokerByMethod instead.
+	InvokerByRequest(request any) (Invoker, error)
+
+	// DerivedClient returns an inter-module client for the ADR-028 derived
+	// module address for the provided key.
+	DerivedClient(key []byte) Client
+
+	// Address is the ADR-028 address of this client against which messages will be authenticated.
+	Address() []byte
+}
+
+// Invoker is an inter-module invoker that has already been resolved to a specific method route.
+type Invoker func(ctx context.Context, request any, opts ...grpc.CallOption) (res any, err error)