From 51950c49a5866a7086464fdb256f0bda5516a697 Mon Sep 17 00:00:00 2001
From: Piotr Biernat <keedosn@gmail.com>
Date: Mon, 28 Nov 2022 12:33:25 +0100
Subject: [PATCH] Plugin initial

---
 go.mod       |  5 +++++
 go.sum       |  2 ++
 requestid.go | 63 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 70 insertions(+)
 create mode 100644 go.mod
 create mode 100644 go.sum
 create mode 100644 requestid.go

diff --git a/go.mod b/go.mod
new file mode 100644
index 0000000..4fbabb3
--- /dev/null
+++ b/go.mod
@@ -0,0 +1,5 @@
+module git.pbiernat.dev/traefik/plugin-requestid
+
+go 1.18
+
+require github.com/google/uuid v1.3.0
diff --git a/go.sum b/go.sum
new file mode 100644
index 0000000..3dfe1c9
--- /dev/null
+++ b/go.sum
@@ -0,0 +1,2 @@
+github.com/google/uuid v1.3.0 h1:t6JiXgmwXMjEs8VusXIJk2BXHsn+wx8BZdTaoZ5fu7I=
+github.com/google/uuid v1.3.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
diff --git a/requestid.go b/requestid.go
new file mode 100644
index 0000000..0123f0c
--- /dev/null
+++ b/requestid.go
@@ -0,0 +1,63 @@
+package requestid
+
+import (
+	"context"
+	"fmt"
+	"net/http"
+
+	"github.com/google/uuid"
+)
+
+const defaultHeaderName = "X-Request-ID"
+
+// Config plugin configuration
+type Config struct {
+	HeaderName string `json:"headerName"`
+}
+
+// CreateConfig create default plugin configuration
+func CreateConfig() *Config {
+	return &Config{
+		HeaderName: defaultHeaderName,
+	}
+}
+
+// RequestIDHeader
+type RequestIDHeader struct {
+	headerName string
+	name       string
+	next       http.Handler
+}
+
+// New create new RequestIDHeader
+func New(ctx context.Context, next http.Handler, config *Config, name string) (http.Handler, error) {
+	hdr := &RequestIDHeader{
+		next: next,
+		name: name,
+	}
+
+	if config == nil {
+		return nil, fmt.Errorf("config can not be nil")
+	}
+
+	if config.HeaderName == "" {
+		hdr.headerName = defaultHeaderName
+	} else {
+		hdr.headerName = config.HeaderName
+	}
+
+	return hdr, nil
+
+}
+
+func (r *RequestIDHeader) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
+	headerArr := req.Header[r.headerName]
+	uuid := uuid.New().String()
+	if len(headerArr) == 0 {
+		req.Header.Add(r.headerName, uuid)
+	} else if headerArr[0] == "" {
+		req.Header[r.headerName][0] = uuid
+	}
+
+	r.next.ServeHTTP(rw, req)
+}