Golang context.WithValue: how to add several key-value pairs

Question

With Go\'s context package it is possible to pass request-specific data to the stack of request handling functions using

func WithValue(parent C         


        

Answer 1

One (functional) way to do it is using currying and closures

r.WithContext(BuildContext(
   r.Context(),
   SchemaId(mySchemaId),
   RequestId(myRequestId),
   Logger(myLogger)
))

func RequestId(id string) partialContextFn {
   return func(ctx context.Context) context.Context {
      return context.WithValue(ctx, requestIdCtxKey, requestId)
   }
}

func BuildContext(ctx context.Context, ctxFns ...partialContextFn) context.Context {
   for f := range ctxFns {
      ctx = f(ctx)
   }

   return ctx
} 

type partialContextFn func(context.Context) context.Context