From 0101eb1bb1ef0c0c275049b0cbc15dd05933a596 Mon Sep 17 00:00:00 2001
From: Roman Mingazeev <direnol@yandex.ru>
Date: Mon, 23 Nov 2020 13:19:50 +0300
Subject: [PATCH] support merge cloud user-data

---
 builder/yandex/cloud_init.go           | 45 ++++++++++++++++++++++++++
 builder/yandex/cloud_init_test.go      | 38 ++++++++++++++++++++++
 builder/yandex/step_create_instance.go | 17 ++++++----
 3 files changed, 93 insertions(+), 7 deletions(-)
 create mode 100644 builder/yandex/cloud_init.go
 create mode 100644 builder/yandex/cloud_init_test.go

diff --git a/builder/yandex/cloud_init.go b/builder/yandex/cloud_init.go
new file mode 100644
index 000000000..46ee4815c
--- /dev/null
+++ b/builder/yandex/cloud_init.go
@@ -0,0 +1,45 @@
+package yandex
+
+import (
+	"bytes"
+	"fmt"
+	"mime/multipart"
+	"net/textproto"
+)
+
+const (
+	defaultContentType  = "text/cloud-config"
+	cloudInitIPv6Config = `#cloud-config
+bootcmd:
+- [ sh, -c, '/usr/bin/env dhclient -6 -D LL -nw -pf /run/dhclient_ipv6.eth0.pid -lf /var/lib/dhcp/dhclient_ipv6.eth0.leases eth0' ]
+`
+)
+
+// MergeCloudUserMetaData allow merge some user-data sections
+func MergeCloudUserMetaData(usersData ...string) (string, error) {
+	buff := new(bytes.Buffer)
+	data := multipart.NewWriter(buff)
+	_, err := buff.WriteString(fmt.Sprintf("Content-Type: multipart/mixed; boundary=\"%s\"\r\n", data.Boundary()))
+	if err != nil {
+		return "", err
+	}
+	_, err = buff.WriteString("MIME-Version: 1.0\r\n\r\n")
+	if err != nil {
+		return "", err
+	}
+
+	for i, userData := range usersData {
+		w, err := data.CreatePart(textproto.MIMEHeader{
+			"Content-Disposition": {fmt.Sprintf("attachment; filename=\"user-data-%d.yaml\"", i)},
+			"Content-Type":        {defaultContentType},
+		})
+		if err != nil {
+			return "", err
+		}
+		_, err = w.Write([]byte(userData))
+		if err != nil {
+			return "", err
+		}
+	}
+	return buff.String(), nil
+}
diff --git a/builder/yandex/cloud_init_test.go b/builder/yandex/cloud_init_test.go
new file mode 100644
index 000000000..7b00b10e0
--- /dev/null
+++ b/builder/yandex/cloud_init_test.go
@@ -0,0 +1,38 @@
+package yandex
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+const (
+	data1 = `
+#cloud-config
+bootcmd:
+  - cmd1
+  - cmd2
+`
+	data2 = `
+#cloud-config
+runcmd:
+  - touch "cmd3"
+  - cmd4
+`
+)
+
+func TestCloudInitMerge(t *testing.T) {
+	merged, err := MergeCloudUserMetaData(
+		data1,
+		data2,
+	)
+
+	require.NoError(t, err)
+	require.NotEmpty(t, merged)
+
+	require.Contains(t, merged, "cmd1")
+	require.Contains(t, merged, "cmd2")
+	require.Contains(t, merged, "\"cmd3\"")
+	require.Contains(t, merged, "cmd4")
+
+}
diff --git a/builder/yandex/step_create_instance.go b/builder/yandex/step_create_instance.go
index 757b24c2a..0e6a99e89 100644
--- a/builder/yandex/step_create_instance.go
+++ b/builder/yandex/step_create_instance.go
@@ -205,14 +205,17 @@ func (s *StepCreateInstance) Run(ctx context.Context, state multistep.StateBag)
 		return stepHaltWithError(state, fmt.Errorf("Error preparing instance metadata: %s", err))
 	}
 
-	// TODO make part metadata prepare process
 	if config.UseIPv6 {
-		// this ugly hack will replace user provided 'user-data'
-		userData := `#cloud-config
-runcmd:
-- [ sh, -c, '/sbin/dhclient -6 -D LL -nw -pf /run/dhclient_ipv6.eth0.pid -lf /var/lib/dhcp/dhclient_ipv6.eth0.leases eth0' ]
-`
-		instanceMetadata["user-data"] = userData
+		ui.Say("Prepare user-data...")
+
+		oldUserData, ok := instanceMetadata["user-data"]
+		if !ok {
+			oldUserData = ""
+		}
+		instanceMetadata["user-data"], err = MergeCloudUserMetaData(oldUserData, cloudInitIPv6Config)
+		if err != nil {
+			return stepHaltWithError(state, fmt.Errorf("Error merge user data configs: %s", err))
+		}
 	}
 
 	req := &compute.CreateInstanceRequest{