From 3e0cc1e717dd80913d4cfde95ef266e32de39550 Mon Sep 17 00:00:00 2001
From: Gyuho Lee <gyuhox@gmail.com>
Date: Tue, 5 Jun 2018 18:25:20 -0700
Subject: [PATCH] etcdmain: add "--cipher-suites" flag

Signed-off-by: Gyuho Lee <gyuhox@gmail.com>
---
 etcdmain/config.go   |  4 ++++
 etcdmain/help.go     |  2 ++
 pkg/flags/strings.go | 38 +++++++++++++++++++++++++++++++++++++-
 3 files changed, 43 insertions(+), 1 deletion(-)

diff --git a/etcdmain/config.go b/etcdmain/config.go
index 50eeffc54..c4a7d409d 100644
--- a/etcdmain/config.go
+++ b/etcdmain/config.go
@@ -191,6 +191,8 @@ func newConfig() *config {
 	fs.StringVar(&cfg.PeerTLSInfo.TrustedCAFile, "peer-trusted-ca-file", "", "Path to the peer server TLS trusted CA file.")
 	fs.BoolVar(&cfg.PeerAutoTLS, "peer-auto-tls", false, "Peer TLS using generated certificates")
 
+	fs.Var(flags.NewStringsValueV2(""), "cipher-suites", "Comma-separated list of supported TLS cipher suites between client/server and peers (empty will be auto-populated by Go).")
+
 	// logging
 	fs.BoolVar(&cfg.Debug, "debug", false, "Enable debug-level logging for etcd.")
 	fs.StringVar(&cfg.LogPkgLevels, "log-package-levels", "", "Specify a particular log level for each etcd package (eg: 'etcdmain=CRITICAL,etcdserver=DEBUG').")
@@ -266,6 +268,8 @@ func (cfg *config) configFromCmdLine() error {
 	cfg.Fallback = cfg.fallback.String()
 	cfg.Proxy = cfg.proxy.String()
 
+	cfg.CipherSuites = flags.StringsFromFlagV2(cfg.FlagSet, "cipher-suites")
+
 	// disable default advertise-client-urls if lcurls is set
 	missingAC := flags.IsSet(cfg.FlagSet, "listen-client-urls") && !flags.IsSet(cfg.FlagSet, "advertise-client-urls")
 	if !cfg.mayBeProxy() && missingAC {
diff --git a/etcdmain/help.go b/etcdmain/help.go
index 0812197fe..b40231112 100644
--- a/etcdmain/help.go
+++ b/etcdmain/help.go
@@ -150,6 +150,8 @@ security flags:
 		path to the peer server TLS trusted CA file.
 	--peer-auto-tls 'false'
 		peer TLS using self-generated certificates if --peer-key-file and --peer-cert-file are not provided.
+	--cipher-suites ''
+		comma-separated list of supported TLS cipher suites between client/server and peers (empty will be auto-populated by Go).
 
 logging flags
 
diff --git a/pkg/flags/strings.go b/pkg/flags/strings.go
index 21ff916a6..b72d4b4da 100644
--- a/pkg/flags/strings.go
+++ b/pkg/flags/strings.go
@@ -14,7 +14,12 @@
 
 package flags
 
-import "errors"
+import (
+	"errors"
+	"flag"
+	"sort"
+	"strings"
+)
 
 // NewStringsFlag creates a new string flag for which any one of the given
 // strings is a valid value, and any other value is an error.
@@ -44,3 +49,34 @@ func (ss *StringsFlag) Set(s string) error {
 func (ss *StringsFlag) String() string {
 	return ss.val
 }
+
+// StringsValueV2 wraps "sort.StringSlice".
+type StringsValueV2 sort.StringSlice
+
+// Set parses a command line set of strings, separated by comma.
+// Implements "flag.Value" interface.
+func (ss *StringsValueV2) Set(s string) error {
+	*ss = strings.Split(s, ",")
+	return nil
+}
+
+// String implements "flag.Value" interface.
+func (ss *StringsValueV2) String() string { return strings.Join(*ss, ",") }
+
+// NewStringsValueV2 implements string slice as "flag.Value" interface.
+// Given value is to be separated by comma.
+func NewStringsValueV2(s string) (ss *StringsValueV2) {
+	if s == "" {
+		return &StringsValueV2{}
+	}
+	ss = new(StringsValueV2)
+	if err := ss.Set(s); err != nil {
+		plog.Panicf("new StringsValueV2 should never fail: %v", err)
+	}
+	return ss
+}
+
+// StringsFromFlagV2 returns a string slice from the flag.
+func StringsFromFlagV2(fs *flag.FlagSet, flagName string) []string {
+	return []string(*fs.Lookup(flagName).Value.(*StringsValueV2))
+}