Add --code-server-version, default latest-preview

Allows users to change which code-server release to download.

Changed downloads to use
https://codesrv-ci.cdr.sh/releases/$release/linux-x86_64/code-server.

Add last-version file in download script to keep track of which version
is cached, otherwise changing versions might result in them not being
downloaded (as curl thinks it's up to date).

Author: deansheather

main.go

@@ -42,6 +42,7 @@ type rootCmd struct {
 	bindAddr          string
 	sshFlags          string
 	uploadCodeServer  string
+	codeServerVersion string
 }
 
 func (c *rootCmd) Spec() cli.CommandSpec {
@@ -59,7 +60,8 @@ func (c *rootCmd) RegisterFlags(fl *pflag.FlagSet) {
 	fl.BoolVar(&c.noReuseConnection, "no-reuse-connection", false, "do not reuse SSH connection via control socket")
 	fl.StringVar(&c.bindAddr, "bind", "", "local bind address for SSH tunnel, in [HOST][:PORT] syntax (default: 127.0.0.1)")
 	fl.StringVar(&c.sshFlags, "ssh-flags", "", "custom SSH flags")
-	fl.StringVar(&c.uploadCodeServer, "upload-code-server", "", "custom code-server binary to upload to the remote host")
+	fl.StringVar(&c.uploadCodeServer, "upload-code-server", "", "custom code-server binary to upload to the remote host, takes precedence over --code-server-version")
+	fl.StringVar(&c.codeServerVersion, "code-server-version", defaultCodeServerVersion, `custom code-server version to download on the remote host, accepts any release name, "latest", or "latest-preview" (changing this may cause issues)`)
 }
 
 func (c *rootCmd) Run(fl *pflag.FlagSet) {
@@ -81,12 +83,13 @@ func (c *rootCmd) Run(fl *pflag.FlagSet) {
 	}
 
 	err := sshCode(host, dir, options{
-		skipSync:         c.skipSync,
-		sshFlags:         c.sshFlags,
-		bindAddr:         c.bindAddr,
-		syncBack:         c.syncBack,
-		reuseConnection:  !c.noReuseConnection,
-		uploadCodeServer: c.uploadCodeServer,
+		skipSync:          c.skipSync,
+		sshFlags:          c.sshFlags,
+		bindAddr:          c.bindAddr,
+		syncBack:          c.syncBack,
+		reuseConnection:   !c.noReuseConnection,
+		uploadCodeServer:  c.uploadCodeServer,
+		codeServerVersion: c.codeServerVersion,
 	})
 
 	if err != nil {

sshcode.go

@@ -20,7 +20,10 @@ import (
 	"golang.org/x/xerrors"
 )
 
-const codeServerPath = "~/.cache/sshcode/sshcode-server"
+const (
+	codeServerPath           = "~/.cache/sshcode/sshcode-server"
+	defaultCodeServerVersion = "latest-preview"
+)
 
 const (
 	sshDirectory               = "~/.ssh"
@@ -29,14 +32,15 @@ const (
 )
 
 type options struct {
-	skipSync         bool
-	syncBack         bool
-	noOpen           bool
-	reuseConnection  bool
-	bindAddr         string
-	remotePort       string
-	sshFlags         string
-	uploadCodeServer string
+	skipSync          bool
+	syncBack          bool
+	noOpen            bool
+	reuseConnection   bool
+	bindAddr          string
+	remotePort        string
+	sshFlags          string
+	uploadCodeServer  string
+	codeServerVersion string
 }
 
 func sshCode(host, dir string, o options) error {
@@ -60,6 +64,10 @@ func sshCode(host, dir string, o options) error {
 		return xerrors.Errorf("failed to find available remote port: %w", err)
 	}
 
+	if o.codeServerVersion == "" {
+		o.codeServerVersion = defaultCodeServerVersion
+	}
+
 	// Check the SSH directory's permissions and warn the user if it is not safe.
 	o.reuseConnection = checkSSHDirectory(sshDirectory, o.reuseConnection)
 
@@ -102,7 +110,7 @@ func sshCode(host, dir string, o options) error {
 		}
 	} else {
 		flog.Info("ensuring code-server is updated...")
-		dlScript := downloadScript(codeServerPath)
+		dlScript := downloadScript(o.codeServerVersion, codeServerPath)
 
 		// Downloads the latest code-server and allows it to be executed.
 		sshCmdStr := fmt.Sprintf("ssh %v %v '/usr/bin/env bash -l'", o.sshFlags, host)
@@ -145,8 +153,8 @@ func sshCode(host, dir string, o options) error {
 	flog.Info("Tunneling remote port %v to %v", o.remotePort, o.bindAddr)
 
 	sshCmdStr :=
-		fmt.Sprintf("ssh -tt -q -L %v:localhost:%v %v %v 'cd %v; %v --host 127.0.0.1 --allow-http --no-auth --port=%v'",
-			o.bindAddr, o.remotePort, o.sshFlags, host, dir, codeServerPath, o.remotePort,
+		fmt.Sprintf("ssh -tt -q -L %v:localhost:%v %v %v 'cd %v; %v --host 127.0.0.1 --port %v %v'",
+			o.bindAddr, o.remotePort, o.sshFlags, host, dir, codeServerPath, o.remotePort, dir,
 		)
 
 	// Starts code-server and forwards the remote port.
@@ -518,25 +526,44 @@ func rsync(src string, dest string, sshFlags string, excludePaths ...string) err
 	return nil
 }
 
-func downloadScript(codeServerPath string) string {
+func downloadURL(codeServerVersion string) string {
+	const baseURL = "https://codesrv-ci.cdr.sh"
+
+	if codeServerVersion == "latest" || codeServerVersion == "latest-preview" {
+		return fmt.Sprintf("%v/%v-linux", baseURL, codeServerVersion)
+	}
+	return fmt.Sprintf("%v/releases/%v/linux-x86_64/code-server", baseURL, codeServerVersion)
+}
+
+func downloadScript(codeServerVersion string, codeServerPath string) string {
+	url := downloadURL(codeServerVersion)
+
 	return fmt.Sprintf(
 		`set -euxo pipefail || exit 1
 
 [ "$(uname -m)" != "x86_64" ] && echo "Unsupported server architecture $(uname -m). code-server only has releases for x86_64 systems." && exit 1
 pkill -f %v || true
 mkdir -p ~/.local/share/code-server %v
 cd %v
+if [ ! -f last-version ] || [ "$(cat last-version)" != "%v" ]; then
+	rm latest-linux %v
+fi
+echo %v > last-version
 curlflags="-o latest-linux"
 if [ -f latest-linux ]; then
 	curlflags="$curlflags -z latest-linux"
 fi
-curl $curlflags https://codesrv-ci.cdr.sh/latest-linux
+curl $curlflags "%v"
 [ -f %v ] && rm %v
 ln latest-linux %v
 chmod +x %v`,
 		codeServerPath,
 		filepath.Dir(codeServerPath),
 		filepath.Dir(codeServerPath),
+		codeServerVersion,
+		codeServerPath,
+		codeServerVersion,
+		url,
 		codeServerPath,
 		codeServerPath,
 		codeServerPath,