From 86d3c9a6fec1d87b3bd032ab812037be0e8c8b1b Mon Sep 17 00:00:00 2001
From: Vojtech Vitek <vojtech.vitek@golang.cz>
Date: Tue, 5 Mar 2024 15:08:55 +0100
Subject: [PATCH] Add README & CLI tool to inspect TraceId timestamp

---
 README.md           | 25 +++++++++++++++++++++++++
 cmd/traceid/main.go | 25 +++++++++++++++++++++++++
 2 files changed, 50 insertions(+)
 create mode 100644 README.md
 create mode 100644 cmd/traceid/main.go

diff --git a/README.md b/README.md
new file mode 100644
index 0000000..072d80a
--- /dev/null
+++ b/README.md
@@ -0,0 +1,25 @@
+# TraceId
+
+Go package that helps create and pass `TraceId` header among microservices for simple tracing capabilities and log grouping.
+
+The generated `TraceId` value is [UUIDv7](https://datatracker.ietf.org/doc/html/draft-peabody-dispatch-new-uuid-format-03#name-uuid-version-7), which lets you infer the time of the trace creation from its value.
+
+## Example
+
+TODO
+
+## Get time from UUIDv7 value
+
+```
+$ go run github.com/go-chi/traceid/cmd/traceid 018e0ee7-3605-7d75-b344-01062c6fd8bc
+2024-03-05 14:56:57.477 +0100 CET
+```
+
+### Create new UUIDv7:
+```
+$ go run github.com/go-chi/traceid/cmd/traceid
+018e0ee7-3605-7d75-b344-01062c6fd8bc
+```
+
+## License
+[MIT](./LICENSE)
\ No newline at end of file
diff --git a/cmd/traceid/main.go b/cmd/traceid/main.go
new file mode 100644
index 0000000..bad6e70
--- /dev/null
+++ b/cmd/traceid/main.go
@@ -0,0 +1,25 @@
+package main
+
+import (
+	"fmt"
+	"log"
+	"os"
+	"time"
+
+	"github.com/google/uuid"
+)
+
+func main() {
+	if len(os.Args) <= 1 {
+		fmt.Println(uuid.Must(uuid.NewV7()))
+		os.Exit(0)
+	}
+
+	uuid, err := uuid.Parse(os.Args[1])
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	t := time.Unix(uuid.Time().UnixTime())
+	fmt.Println(t)
+}