From e67d892ea3f43877e9f45c566863455fc9e95e44 Mon Sep 17 00:00:00 2001
From: Clint Shryock <clint@ctshryock.com>
Date: Wed, 23 Sep 2015 23:15:28 -0500
Subject: [PATCH] driver/qemu: Setup multiple port forwards

---
 client/driver/qemu.go      | 47 ++++++++++++++++++++++++++++++--------
 client/driver/qemu_test.go | 16 +++++++------
 2 files changed, 47 insertions(+), 16 deletions(-)

diff --git a/client/driver/qemu.go b/client/driver/qemu.go
index 32589c696..25298a8cb 100644
--- a/client/driver/qemu.go
+++ b/client/driver/qemu.go
@@ -14,6 +14,7 @@ import (
 	"path/filepath"
 	"regexp"
 	"runtime"
+	"strconv"
 	"strings"
 	"syscall"
 	"time"
@@ -71,7 +72,7 @@ func (d *QemuDriver) Fingerprint(cfg *config.Config, node *structs.Node) (bool,
 		return false, fmt.Errorf("Unable to parse Qemu version string: %#v", matches)
 	}
 
-	node.Attributes["driver.qemu"] = "true"
+	node.Attributes["driver.qemu"] = "1"
 	node.Attributes["driver.qemu.version"] = matches[1]
 
 	return true, nil
@@ -92,6 +93,10 @@ func (d *QemuDriver) Start(ctx *ExecContext, task *structs.Task) (DriverHandle,
 		return nil, fmt.Errorf("Missing required Task Resource: Memory")
 	}
 
+	if len(task.Resources.Networks) == 0 {
+		return nil, fmt.Errorf("[WARN] driver.qemu: No networks are available for port mapping")
+	}
+
 	// Attempt to download the thing
 	// Should be extracted to some kind of Http Fetcher
 	// Right now, assume publicly accessible HTTP url
@@ -162,16 +167,40 @@ func (d *QemuDriver) Start(ctx *ExecContext, task *structs.Task) (DriverHandle,
 
 	// TODO: Consolidate these into map of host/guest port when we have HCL
 	// Note: Host port must be open and available
-	if task.Config["guest_port"] != "" && task.Config["host_port"] != "" {
-		args = append(args,
-			"-netdev",
-			fmt.Sprintf("user,id=user.0,hostfwd=tcp::%s-:%s",
-				task.Config["host_port"],
-				task.Config["guest_port"]),
-			"-device", "virtio-net,netdev=user.0",
-		)
+	// Get and split guest ports. The guest_ports configuration must match up with
+	// the Reserved ports in the Task Resources
+	// Users can supply guest_hosts as a list of posts to map on the guest vm.
+	// These map 1:1 with the requested Reserved Ports from the hostmachine.
+	ports := strings.Split(task.Config["guest_ports"], ",")
+	if len(ports) == 0 {
+		return nil, fmt.Errorf("[ERR] driver.qemu: Error parsing required Guest Ports")
 	}
 
+	// TODO: support more than a single, default Network
+	if len(ports) != len(task.Resources.Networks[0].ReservedPorts) {
+		return nil, fmt.Errorf("[ERR] driver.qemu: Error matching Guest Ports with Reserved ports")
+	}
+
+	// Loop through the reserved ports and construct the hostfwd string, to map
+	// reserved ports to the ports listenting in the VM
+	// Ex:
+	//    hostfwd=tcp::22000-:22,hostfwd=tcp::80-:8080
+	reservedPorts := task.Resources.Networks[0].ReservedPorts
+	var forwarding string
+	for i, p := range ports {
+		forwarding = fmt.Sprintf("%s,hostfwd=tcp::%s-:%s", forwarding, strconv.Itoa(reservedPorts[i]), p)
+	}
+
+	if "" == forwarding {
+		return nil, fmt.Errorf("[ERR] driver.qemu:  Error constructing port forwarding")
+	}
+
+	args = append(args,
+		"-netdev",
+		fmt.Sprintf("user,id=user.0%s", forwarding),
+		"-device", "virtio-net,netdev=user.0",
+	)
+
 	// If using KVM, add optimization args
 	if accelerator == "kvm" {
 		args = append(args,
diff --git a/client/driver/qemu_test.go b/client/driver/qemu_test.go
index 0acde6a39..e7f216708 100644
--- a/client/driver/qemu_test.go
+++ b/client/driver/qemu_test.go
@@ -55,14 +55,16 @@ func TestQemuDriver_Start(t *testing.T) {
 			"image_source": "https://dl.dropboxusercontent.com/u/47675/jar_thing/linux-0.2.img",
 			"checksum":     "a5e836985934c3392cbbd9b26db55a7d35a8d7ae1deb7ca559dd9c0159572544",
 			"accelerator":  "tcg",
-			"host_port":    "8080",
-			"guest_port":   "8081",
+			"guest_ports":  "22,8080",
+		},
+		Resources: &structs.Resources{
+			MemoryMB: 512,
+			Networks: []*structs.NetworkResource{
+				&structs.NetworkResource{
+					ReservedPorts: []int{22000, 80},
+				},
+			},
 		},
-	}
-
-	// add requred memory resource
-	task.Resources = &structs.Resources{
-		MemoryMB: 512,
 	}
 
 	handle, err := d.Start(ctx, task)