Use gorilla/mux for middleware and extend

- Use gorilla/mux for middleware.
- Add Dumper, RequestID, and Logger middlewares.
- Add makeURL helper

internal/middleware/request_id.go

@@ -0,0 +1,98 @@
+package middleware
+
+// Derived from Goa project, MIT Licensed
+// https://github.com/goadesign/goa/blob/v3/http/middleware/requestid.go
+
+import (
+	"context"
+	"net/http"
+
+	"github.com/gofrs/uuid"
+)
+
+// Key to use when setting the request ID.
+type ctxKeyRequestID int
+
+// RequestIDKey is the key that holds the unique request ID in a request context.
+const RequestIDKey ctxKeyRequestID = 0
+
+// RequestID is a middleware that injects a request ID into the context of each
+// request.
+func RequestID(options ...RequestIDOption) func(http.Handler) http.Handler {
+	o := newRequestIDOptions(options...)
+
+	return func(next http.Handler) http.Handler {
+		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			ctx := r.Context()
+
+			var id string
+
+			if o.UseRequestID() {
+				id = r.Header.Get("X-Request-Id")
+				if o.requestIDLimit > 0 && len(id) > o.requestIDLimit {
+					id = id[:o.requestIDLimit]
+				}
+			}
+
+			if id == "" {
+				id = uuid.Must(uuid.NewV4()).String()[:6]
+			}
+
+			ctx = context.WithValue(ctx, RequestIDKey, id)
+			next.ServeHTTP(w, r.WithContext(ctx))
+		})
+	}
+}
+
+// GetReqID returns a request ID from the given context if one is present.
+// Returns the empty string if a request ID cannot be found.
+func GetReqID(ctx context.Context) string {
+	if ctx == nil {
+		return ""
+	}
+	if reqID, ok := ctx.Value(RequestIDKey).(string); ok {
+		return reqID
+	}
+	return ""
+}
+
+func UseXRequestIDHeaderOption(f bool) RequestIDOption {
+	return func(o *RequestIDOptions) *RequestIDOptions {
+		o.useXRequestID = f
+		return o
+	}
+}
+
+func XRequestIDLimitOption(limit int) RequestIDOption {
+	return func(o *RequestIDOptions) *RequestIDOptions {
+		o.requestIDLimit = limit
+		return o
+	}
+}
+
+type (
+	RequestIDOption func(*RequestIDOptions) *RequestIDOptions
+
+	RequestIDOptions struct {
+		// useXRequestID enabled the use of the X-Request-Id request header as
+		// the request ID.
+		useXRequestID bool
+
+		// requestIDLimit is the maximum length of the X-Request-Id header
+		// allowed. Values longer than this value are truncated. Zero value
+		// means no limit.
+		requestIDLimit int
+	}
+)
+
+func newRequestIDOptions(options ...RequestIDOption) *RequestIDOptions {
+	o := new(RequestIDOptions)
+	for _, opt := range options {
+		o = opt(o)
+	}
+	return o
+}
+
+func (o *RequestIDOptions) UseRequestID() bool {
+	return o.useXRequestID
+}