worker: add some type safety to port handling

The "port" used for build jobs is an actual TCP port (used e.g. for SSH
access). It is already enforced to be in a specific port range when
initially selected. Enshrine this fact in the API by making it a uint16.

worker/context.go

@@ -54,7 +54,7 @@ type JobContext struct {
 	LogDir      string
 	LogFile     *os.File
 	Manifest    *Manifest
-	Port        int
+	Port        uint16
 	Settled     bool
 
 	NTasks int
@@ -261,11 +261,10 @@ func (ctx *JobContext) Control(
 }
 
 func (ctx *JobContext) SSH(args ...string) *exec.Cmd {
-	sport := strconv.Itoa(ctx.Port)
 	switch ctx.ImageConfig.LoginCmd {
 	case "drawterm":
 		return exec.CommandContext(ctx.Context,
-			"env", fmt.Sprintf("DIALSRV=%s", sport),
+			"env", fmt.Sprintf("DIALSRV=%d", ctx.Port),
 			"PASS=password", "drawterm",
 			"-a", "none",
 			"-u", "glenda",
@@ -274,7 +273,7 @@ func (ctx *JobContext) SSH(args ...string) *exec.Cmd {
 	case "ssh":
 		return exec.CommandContext(ctx.Context, "ssh",
 			append([]string{"-q",
-				"-p", sport,
+				"-p", fmt.Sprintf("%d", ctx.Port),
 				"-o", "UserKnownHostsFile=/dev/null",
 				"-o", "StrictHostKeyChecking=no",
 				"-o", "LogLevel=quiet",

worker/http.go

@@ -37,7 +37,7 @@ func HttpServer() {
 					Manifest string  `json:"manifest"`
 					Note     *string `json:"note"`
 					OwnerId  int     `json:"owner_id"`
-					Port     int     `json:"port"`
+					Port     uint16  `json:"port"`
 					Status   string  `json:"status"`
 					Task     int     `json:"task"`
 					Tasks    int     `json:"tasks"`

worker/tasks.go

@@ -65,12 +65,12 @@ func (ctx *JobContext) Boot(r *goredis.Client) func() {
 	if ctx.Manifest.Arch != nil {
 		arch = *ctx.Manifest.Arch
 	}
-	ctx.Port = int(port)
+	ctx.Port = uint16(port)
 	ctx.Log.Printf("Booting image %s (%s) on port %d",
 		ctx.Manifest.Image, arch, port)
 
 	boot := ctx.Control(ctx.Context,
-		ctx.Manifest.Image, "boot", arch, strconv.Itoa(ctx.Port))
+		ctx.Manifest.Image, "boot", arch, fmt.Sprintf("%d", ctx.Port))
 	boot.Env = append(os.Environ(), fmt.Sprintf("BUILD_JOB_ID=%d", ctx.Job.Id))
 	boot.Stdout = ctx.LogFile
 	boot.Stderr = ctx.LogFile
@@ -83,7 +83,7 @@ func (ctx *JobContext) Boot(r *goredis.Client) func() {
 	return func() {
 		ctx.Log.Printf("Tearing down build VM")
 		cleanup := ctx.Control(context.TODO(), ctx.Manifest.Image, "cleanup",
-			strconv.Itoa(ctx.Port))
+			fmt.Sprintf("%d", ctx.Port))
 		if err := cleanup.Run(); err != nil {
 			fmt.Printf("Failed to destroy build VM: %v\n", err)
 		}
@@ -388,7 +388,7 @@ func (ctx *JobContext) ConfigureRepos() error {
 	for name, source := range ctx.Manifest.Repositories {
 		ctx.Log.Printf("Adding repository %s\n", name)
 		ctrl := ctx.Control(ctx.Context, ctx.Manifest.Image, "add-repo",
-			strconv.Itoa(ctx.Port), name, source)
+			fmt.Sprintf("%d", ctx.Port), name, source)
 		ctrl.Stdout = ctx.LogFile
 		ctrl.Stderr = ctx.LogFile
 		if err := ctrl.Run(); err != nil {
@@ -540,7 +540,7 @@ func (ctx *JobContext) InstallPackages() error {
 	}
 	ctx.Log.Println("Installing packages")
 	ctrl := ctx.Control(ctx.Context, ctx.Manifest.Image, "install",
-		strconv.Itoa(ctx.Port), strings.Join(ctx.Manifest.Packages, " "))
+		fmt.Sprintf("%d", ctx.Port), strings.Join(ctx.Manifest.Packages, " "))
 	ctrl.Stdout = ctx.LogFile
 	ctrl.Stderr = ctx.LogFile
 	if err := ctrl.Run(); err != nil {