accept key from env var

main.go

@@ -211,6 +211,8 @@ type autocertCache struct {
 	value string
 }
 
+const envCacheEncKey = "DUMBPROXY_CACHE_ENC_KEY"
+
 type CLIArgs struct {
 	bindAddress               string
 	bindReusePort             bool
@@ -275,6 +277,7 @@ func parse_args() CLIArgs {
 			value: filepath.Join(home, ".dumbproxy", "autocert"),
 		},
 	}
+	args.autocertCacheEncKey.Set(os.Getenv(envCacheEncKey))
 	flag.StringVar(&args.bindAddress, "bind-address", ":8080", "HTTP proxy listen address. Set empty value to use systemd socket activation.")
 	flag.BoolVar(&args.bindReusePort, "bind-reuseport", false, "allow multiple server instances on the same port")
 	flag.StringVar(&args.bindPprof, "bind-pprof", "", "enables pprof debug endpoints")
@@ -312,7 +315,7 @@ func parse_args() CLIArgs {
 		return nil
 	})
 	flag.StringVar(&args.autocertCacheRedisPrefix, "autocert-cache-redis-prefix", "", "prefix to use for keys in Redis or Redis Cluster cache")
-	flag.Var(&args.autocertCacheEncKey, "autocert-cache-enc-key", "hex-encoded encryption key for cert cache entries")
+	flag.Var(&args.autocertCacheEncKey, "autocert-cache-enc-key", "hex-encoded encryption key for cert cache entries. Can be also set with "+envCacheEncKey+" environment variable")
 	flag.StringVar(&args.autocertACME, "autocert-acme", autocert.DefaultACMEDirectory, "custom ACME endpoint")
 	flag.StringVar(&args.autocertEmail, "autocert-email", "", "email used for ACME registration")
 	flag.StringVar(&args.autocertHTTP, "autocert-http", "", "listen address for HTTP-01 challenges handler of ACME")