From 54e58f280802c7a0816b89e9a5ab498aa31143d4 Mon Sep 17 00:00:00 2001
From: Justin Cormack <justin.cormack@docker.com>
Date: Sun, 4 Jun 2017 17:50:13 +0100
Subject: [PATCH] Allow specification of multiple yaml files for a single build

Each section will be appended in order of the CLI, other then
kernel where last specified one wins.

This is useful if you eg want to have a base version for (say)
AWS and GCP and then add your own image on top.

Signed-off-by: Justin Cormack <justin.cormack@docker.com>
---
 cmd/moby/build.go  | 61 +++++++++++++++++++++++++---------------------
 cmd/moby/config.go | 19 +++++++++++++++
 2 files changed, 52 insertions(+), 28 deletions(-)

diff --git a/cmd/moby/build.go b/cmd/moby/build.go
index 97ad5a563..6f82613ad 100644
--- a/cmd/moby/build.go
+++ b/cmd/moby/build.go
@@ -87,41 +87,46 @@ func build(args []string) {
 	}
 
 	name := *buildName
-	var config []byte
-	if conf := remArgs[0]; conf == "-" {
-		var err error
-		config, err = ioutil.ReadAll(os.Stdin)
-		if err != nil {
-			log.Fatalf("Cannot read stdin: %v", err)
-		}
-		if name == "" {
-			name = defaultNameForStdin
-		}
-	} else {
-		if !(filepath.Ext(conf) == ".yml" || filepath.Ext(conf) == ".yaml") {
-			conf = conf + ".yml"
-		}
-		var err error
-		config, err = ioutil.ReadFile(conf)
-		if err != nil {
-			log.Fatalf("Cannot open config file: %v", err)
-		}
-		if name == "" {
-			name = strings.TrimSuffix(filepath.Base(conf), filepath.Ext(conf))
-		}
-	}
 
-	m, err := NewConfig(config)
-	if err != nil {
-		log.Fatalf("Invalid config: %v", err)
+	var moby Moby
+	for _, arg := range remArgs {
+		var config []byte
+		if conf := arg; conf == "-" {
+			var err error
+			config, err = ioutil.ReadAll(os.Stdin)
+			if err != nil {
+				log.Fatalf("Cannot read stdin: %v", err)
+			}
+			if name == "" {
+				name = defaultNameForStdin
+			}
+		} else {
+			if !(filepath.Ext(conf) == ".yml" || filepath.Ext(conf) == ".yaml") {
+				conf = conf + ".yml"
+			}
+			var err error
+			config, err = ioutil.ReadFile(conf)
+			if err != nil {
+				log.Fatalf("Cannot open config file: %v", err)
+			}
+			if name == "" {
+				name = strings.TrimSuffix(filepath.Base(conf), filepath.Ext(conf))
+			}
+		}
+
+		m, err := NewConfig(config)
+		if err != nil {
+			log.Fatalf("Invalid config: %v", err)
+		}
+		moby = AppendConfig(moby, m)
 	}
 
 	if *buildDisableTrust {
 		log.Debugf("Disabling content trust checks for this build")
-		m.Trust = TrustConfig{}
+		moby.Trust = TrustConfig{}
 	}
 
-	image := buildInternal(m, *buildPull)
+	image := buildInternal(moby, *buildPull)
 
 	log.Infof("Create outputs:")
 	err = outputs(filepath.Join(*buildDir, name), image, buildOut, size, *buildHyperkit)
diff --git a/cmd/moby/config.go b/cmd/moby/config.go
index fa6c5a4d1..39ab61098 100644
--- a/cmd/moby/config.go
+++ b/cmd/moby/config.go
@@ -135,6 +135,25 @@ func NewConfig(config []byte) (Moby, error) {
 	return m, nil
 }
 
+// AppendConfig appends two configs.
+func AppendConfig(m0, m1 Moby) Moby {
+	moby := m0
+	if m1.Kernel.Image != "" {
+		moby.Kernel.Image = m1.Kernel.Image
+	}
+	if m1.Kernel.Cmdline != "" {
+		moby.Kernel.Cmdline = m1.Kernel.Cmdline
+	}
+	moby.Init = append(moby.Init, m1.Init...)
+	moby.Onboot = append(moby.Onboot, m1.Onboot...)
+	moby.Services = append(moby.Services, m1.Services...)
+	moby.Files = append(moby.Files, m1.Files...)
+	moby.Trust.Image = append(moby.Trust.Image, m1.Trust.Image...)
+	moby.Trust.Org = append(moby.Trust.Org, m1.Trust.Org...)
+
+	return moby
+}
+
 // NewImage validates an parses yaml or json for a MobyImage
 func NewImage(config []byte) (MobyImage, error) {
 	log.Debugf("Reading label config: %s", string(config))