From 3bcb83e55b3a9dcc8a39c0afef9be70001bca571 Mon Sep 17 00:00:00 2001
From: afg <afg984@gmail.com>
Date: Tue, 28 Aug 2018 07:35:41 +0800
Subject: [PATCH] Allow {{ ServerHost }} in --cmdline

---
 pixiecore/booters.go   | 8 ++++++--
 pixiecore/http.go      | 8 ++++++--
 pixiecore/pixiecore.go | 7 ++++---
 3 files changed, 16 insertions(+), 7 deletions(-)

diff --git a/pixiecore/booters.go b/pixiecore/booters.go
index a83daa8..6c2ec18 100644
--- a/pixiecore/booters.go
+++ b/pixiecore/booters.go
@@ -30,6 +30,10 @@ import (
 	"time"
 )
 
+func dummyServerHost() string {
+	return "{{ ServerHost }}"
+}
+
 // StaticBooter boots all machines with the same Spec.
 //
 // IDs in spec should be either local file paths, or HTTP/HTTPS URLs.
@@ -50,7 +54,7 @@ func StaticBooter(spec *Spec) (Booter, error) {
 		ret.otherIDs = append(ret.otherIDs, id)
 		return fmt.Sprintf("{{ ID \"other-%d\" }}", len(ret.otherIDs)-1)
 	}
-	cmdline, err := expandCmdline(spec.Cmdline, template.FuncMap{"ID": f})
+	cmdline, err := expandCmdline(spec.Cmdline, template.FuncMap{"ID": f, "ServerHost": dummyServerHost})
 	if err != nil {
 		return nil, err
 	}
@@ -237,7 +241,7 @@ func (b *apibooter) BootSpec(m Machine) (*Spec, error) {
 		}
 		return fmt.Sprintf("{{ ID %q }}", id), nil
 	}
-	ret.Cmdline, err = expandCmdline(ret.Cmdline, template.FuncMap{"URL": f})
+	ret.Cmdline, err = expandCmdline(ret.Cmdline, template.FuncMap{"URL": f, "ServerHost": dummyServerHost})
 	if err != nil {
 		return nil, err
 	}
diff --git a/pixiecore/http.go b/pixiecore/http.go
index cfc0e98..55d2705 100644
--- a/pixiecore/http.go
+++ b/pixiecore/http.go
@@ -207,10 +207,14 @@ func ipxeScript(mach Machine, spec *Spec, serverHost string) ([]byte, error) {
 		fmt.Fprintf(&b, "initrd=initrd%d ", i)
 	}
 
-	f := func(id string) string {
+	idFunc := func(id string) string {
 		return fmt.Sprintf("http://%s/_/file?name=%s", serverHost, url.QueryEscape(id))
 	}
-	cmdline, err := expandCmdline(spec.Cmdline, template.FuncMap{"ID": f})
+	serverHostFunc := func() string {
+		return serverHost
+	}
+	cmdline, err := expandCmdline(spec.Cmdline,
+		template.FuncMap{"ID": idFunc, "ServerHost": serverHostFunc})
 	if err != nil {
 		return nil, fmt.Errorf("expanding cmdline %q: %s", spec.Cmdline, err)
 	}
diff --git a/pixiecore/pixiecore.go b/pixiecore/pixiecore.go
index a9c831f..cbbbe87 100644
--- a/pixiecore/pixiecore.go
+++ b/pixiecore/pixiecore.go
@@ -77,9 +77,10 @@ type Spec struct {
 	// Optional init ramdisks for linux kernels
 	Initrd []ID
 	// Optional kernel commandline. This string is evaluated as a
-	// text/template template, in which "ID(x)" function is
-	// available. Invoking ID(x) returns a URL that will call
-	// Booter.ReadBootFile(x) when fetched.
+	// text/template template, in which these functions are available:
+	// "ID(x)": returns a URL that will call
+	//          Booter.ReadBootFile(x) when fetched.
+	// "ServerHost()": returns the server address of the http server
 	Cmdline string
 	// Message to print on the client machine before booting.
 	Message string