Add health output plugin (#5882)

internal/http.go

@@ -0,0 +1,45 @@
+package internal
+
+import (
+	"crypto/subtle"
+	"net/http"
+)
+
+// ErrorFunc is a callback for writing an error response.
+type ErrorFunc func(rw http.ResponseWriter, code int)
+
+// AuthHandler returns a http handler that requires HTTP basic auth
+// credentials to match the given username and password.
+func AuthHandler(username, password string, onError ErrorFunc) func(h http.Handler) http.Handler {
+	return func(h http.Handler) http.Handler {
+		return &basicAuthHandler{
+			username: username,
+			password: password,
+			onError:  onError,
+			next:     h,
+		}
+	}
+
+}
+
+type basicAuthHandler struct {
+	username string
+	password string
+	onError  ErrorFunc
+	next     http.Handler
+}
+
+func (h *basicAuthHandler) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
+	if h.username != "" || h.password != "" {
+		reqUsername, reqPassword, ok := req.BasicAuth()
+		if !ok ||
+			subtle.ConstantTimeCompare([]byte(reqUsername), []byte(h.username)) != 1 ||
+			subtle.ConstantTimeCompare([]byte(reqPassword), []byte(h.password)) != 1 {
+
+			h.onError(rw, http.StatusUnauthorized)
+			return
+		}
+	}
+
+	h.next.ServeHTTP(rw, req)
+}

internal/internal.go

@@ -64,7 +64,8 @@ func Version() string {
 
 // ProductToken returns a tag for Telegraf that can be used in user agents.
 func ProductToken() string {
-	return fmt.Sprintf("Telegraf/%s Go/%s", Version(), runtime.Version())
+	return fmt.Sprintf("Telegraf/%s Go/%s",
+		Version(), strings.TrimPrefix(runtime.Version(), "go"))
 }
 
 // UnmarshalTOML parses the duration from the TOML config file