Add --version flag.

gen_version.sh

@@ -0,0 +1,19 @@
+#!/bin/sh
+
+v=$(git tag --contains HEAD)
+if [ "$v" = "" ]; then
+ echo "Cannot determine tag." >&2
+ exit 1
+fi
+
+v=$(echo "$v" | sed -Ee 's#^v(.*)#\1#')
+
+cat <<END >version.go
+// Code generated by gen_version.sh, DO NOT EDIT.
+
+package main
+
+//go:generate sh -c ./gen_version.sh
+
+const version = "$v"
+END

main.go

@@ -9,7 +9,7 @@ import (
 
  "github.com/fatih/color"
  "github.com/spf13/pflag"
- "k8s.io/api/core/v1"
+ v1 "k8s.io/api/core/v1"
  "k8s.io/apimachinery/pkg/labels"
  "k8s.io/client-go/kubernetes"
  _ "k8s.io/client-go/plugin/pkg/client/auth/gcp"
@@ -29,6 +29,7 @@ func main() {
  raw bool
  tmplString string
  sinceStart bool
+ showVersion bool
  includePatterns []*regexp.Regexp
  excludePatternStrings []string
  )
@@ -55,12 +56,18 @@ func main() {
  flags.BoolVarP(&quiet, "quiet", "q", false, "Don't print events about new/deleted pods")
  flags.BoolVarP(&sinceStart, "since-start", "s", false,
  "Start reading log from the beginning of the container's lifetime.")
+ flags.BoolVarP(&showVersion, "version", "", false, "Show version.")
 
  if err := flags.Parse(os.Args[1:]); err != nil {
  fail(err.Error())
  os.Exit(1)
  }
 
+ if showVersion {
+ fmt.Printf("ktail %s\n", version)
+ os.Exit(0)
+ }
+
  var excludePatterns []*regexp.Regexp
  for _, p := range excludePatternStrings {
  r, err := regexp.Compile(p)