App version is taken from version.json compiled in (#149)

* App version is taken from version.json compiled in

This ensures that the version is always set to the correct value. making version.json the source of truth.

Fixes #146
Fixes #113

* remove version number from README
* include date and dirty flag in version

README.md

@@ -48,7 +48,7 @@ USAGE:
    ipget [global options] command [command options] [arguments...]
 
 VERSION:
-   0.9.2
+   see version.json
 
 COMMANDS:
    help, h  Shows a list of commands or help for one command

main.go

@@ -32,7 +32,7 @@ func main() {
 	app := cli.NewApp()
 	app.Name = "ipget"
 	app.Usage = "Retrieve and save IPFS objects."
-	app.Version = "0.9.2"
+	app.Version = version
 	app.Flags = []cli.Flag{
 		&cli.StringFlag{
 			Name:    "output",

version.go

@@ -0,0 +1,51 @@
+package main
+
+import (
+	_ "embed"
+	"encoding/json"
+	"fmt"
+	"runtime/debug"
+	"time"
+)
+
+//go:embed version.json
+var versionJSON []byte
+
+var version = buildVersion()
+
+func buildVersion() string {
+	// Read version from embedded JSON file.
+	var v struct {
+		Version string `json:"version"`
+	}
+	json.Unmarshal(versionJSON, &v)
+	release := v.Version
+
+	info, ok := debug.ReadBuildInfo()
+	if !ok {
+		return release + " dev-build"
+	}
+
+	var dirty bool
+	var day, revision string
+
+	// Append the revision to the version.
+	for _, kv := range info.Settings {
+		switch kv.Key {
+		case "vcs.revision":
+			revision = kv.Value[:7]
+		case "vcs.time":
+			t, _ := time.Parse(time.RFC3339, kv.Value)
+			day = t.UTC().Format("2006-01-02")
+		case "vcs.modified":
+			dirty = kv.Value == "true"
+		}
+	}
+	if dirty {
+		revision += "-dirty"
+	}
+	if revision != "" {
+		return fmt.Sprintf("%s %s-%s", release, day, revision)
+	}
+	return release + " dev-build"
+}