Fixed bug #1240667: pin priority for cloud-tools

cloudinit/cloudinit.go

Index: cloudinit/cloudinit.go
=== modified file 'cloudinit/cloudinit.go'
--- cloudinit/cloudinit.go	2013-11-26 12:24:48 +0000
+++ cloudinit/cloudinit.go	2014-02-11 18:24:44 +0000
@@ -7,6 +7,9 @@
 package cloudinit
 
 import (
+	"bytes"
+	"text/template"
+
 	yaml "launchpad.net/goyaml"
 )
 
@@ -38,10 +41,41 @@
 }
 
 // AptSource is an apt(8) source, comprising a source location,
-// with an optional Key.
+// with an optional Key, and optional apt_preferences(5).
 type AptSource struct {
-	Source string `yaml:"source"`
-	Key    string `yaml:"key,omitempty"`
+	Source string          `yaml:"source"`
+	Key    string          `yaml:"key,omitempty"`
+	Prefs  *AptPreferences `yaml:"-"`
+}
+
+// AptPreferences is a set of apt_preferences(5) compatible
+// preferences for an apt source. It can be used to override the
+// default priority for the source. Path where the file will be
+// created (usually in /etc/apt/preferences.d/).
+type AptPreferences struct {
+	Path        string
+	Explanation string
+	Package     string
+	Pin         string
+	PinPriority int
+}
+
+// FileContents generates an apt_preferences(5) file from the fields
+// in prefs.
+func (prefs *AptPreferences) FileContents() string {
+	const prefTemplate = `
+Explanation: {{.Explanation}}
+Package: {{.Package}}
+Pin: {{.Pin}}
+Pin-Priority: {{.PinPriority}}
+`
+	var buf bytes.Buffer
+	t := template.Must(template.New("").Parse(prefTemplate[1:]))
+	err := t.Execute(&buf, prefs)
+	if err != nil {
+		panic(err)
+	}
+	return buf.String()
 }
 
 // command represents a shell command.