feat(auth): X-Auth-Request-User context middleware

internal/auth/caller.go

@@ -0,0 +1,26 @@
+package auth
+
+import (
+	"context"
+	"net/http"
+)
+
+type ctxKey struct{}
+
+func CallerMiddleware(next http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		user := r.Header.Get("X-Auth-Request-User")
+		if user == "" {
+			user = r.Header.Get("X-Forwarded-User")
+		}
+		ctx := context.WithValue(r.Context(), ctxKey{}, user)
+		next.ServeHTTP(w, r.WithContext(ctx))
+	})
+}
+
+func Caller(ctx context.Context) string {
+	if v, ok := ctx.Value(ctxKey{}).(string); ok {
+		return v
+	}
+	return ""
+}