/
id.go
85 lines (73 loc) · 2.19 KB
/
id.go
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// Copyright © 2019 The Things Network Foundation, The Things Industries B.V.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package middleware
import (
"crypto/rand"
"fmt"
"net/http"
"time"
echo "github.com/labstack/echo/v4"
ulid "github.com/oklog/ulid/v2"
)
// used to mock time
var now = time.Now
// ID adds a request id to the request.
func ID(prefix string) echo.MiddlewareFunc {
gen := newID(prefix)
return func(next echo.HandlerFunc) echo.HandlerFunc {
return func(c echo.Context) error {
id := c.Request().Header.Get(echo.HeaderXRequestID)
if id == "" {
var err error
id, err = gen.generate()
if err != nil {
return echo.NewHTTPError(http.StatusInternalServerError, fmt.Sprintf("Failed to generate request ID: %s", err))
}
}
c.Request().Header.Set(echo.HeaderXRequestID, id)
c.Request().Header.Set("Grpc-Metadata-Request-ID", id)
c.Response().Header().Set(echo.HeaderXRequestID, id)
return next(c)
}
}
}
// id a generator of new ids, which uses ULID under the hood.
type id struct {
prefixer func(ulid.ULID) string
}
// newID creates a new id.
func newID(prefix string) *id {
return &id{
prefixer: prefixer(prefix),
}
}
// generate generates a new ULID.
func (i *id) generate() (string, error) {
id, err := ulid.New(ulid.Timestamp(now()), rand.Reader)
if err != nil {
return "", fmt.Errorf("Failed to generate a new ULID")
}
return i.prefixer(id), nil
}
// prefixer returns a function that can smartly prefix the request id.
func prefixer(prefix string) func(ulid.ULID) string {
if prefix == "" {
return func(id ulid.ULID) string {
return id.String()
}
}
return func(id ulid.ULID) string {
return prefix + "." + id.String()
}
}