Last Updated: April 15, 2021

Go context with value

ctx := Pipe(context.TODO(), SetRequestID("some_value"))
...
reqId, _ := GetRequestId(ctx)

Using this code, you can implement a pipe to set safe context values. Also, it gives at least some guarantees that there is value in the context.

const (
 RequestId = iota
 UserId
 UserToken
)

type PipeFunc func(ctx context.Context) context.Context

func Pipe(ctx context.Context, fns ...PipeFunc) context.Context {
 for _, fn := range fns {
 ctx = fn(ctx)
 }

 return ctx
}

func SetRequestID(requestID string) PipeFunc {
 return func(ctx context.Context) context.Context {
 return context.WithValue(ctx, RequestId, requestID)
 }
}

func GetRequestId(ctx context.Context) (string, error) {
 if id, ok := ctx.Value(RequestId).(string); ok {
 return id, nil
 }

 return "", errors.New("empty requestId")
}

#golang

#go