cmd/tsconnect: pin yarn and node

Adds a tool/yarn helper script that uses specific versions of yarn and
node, downloading them if necessary.

Modeled after tool/go (and the yarn and node Redo scripts from the
corp repo).

Also allows the path to yarn to be overidden (in case the user does not
want to use this script) and always pipes yarn output (to make debugging
and viewing of process easier).

Signed-off-by: Mihai Parparita <mihai@tailscale.com>

cmd/tsconnect/common.go

@@ -97,11 +97,10 @@ func buildWasm(dev bool) error {
 // installJSDeps installs the JavaScript dependencies specified by package.json
 func installJSDeps() error {
 	log.Printf("Installing JS deps...\n")
-	stdoutStderr, err := exec.Command("yarn").CombinedOutput()
-	if err != nil {
-		log.Printf("yarn failed: %s", stdoutStderr)
-	}
-	return err
+	cmd := exec.Command(*yarnPath)
+	cmd.Stdout = os.Stdout
+	cmd.Stderr = os.Stderr
+	return cmd.Run()
 }
 
 // EsbuildMetadata is the subset of metadata struct (described by

cmd/tsconnect/tsconnect.go

@@ -18,8 +18,9 @@ import (
 )
 
 var (
-	addr    = flag.String("addr", ":9090", "address to listen on")
-	distDir = flag.String("distdir", "./dist", "path of directory to place build output in")
+	addr     = flag.String("addr", ":9090", "address to listen on")
+	distDir  = flag.String("distdir", "./dist", "path of directory to place build output in")
+	yarnPath = flag.String("yarnpath", "../../tool/yarn", "path yarn executable used to install JavaScript dependencies")
 )
 
 func main() {

tool/node.rev

@@ -0,0 +1 @@
+16.4.1

tool/yarn

@@ -0,0 +1,79 @@
+#!/bin/sh
+#
+# This script acts like the "yarn" command, but uses Tailscale's
+# currently-desired version, downloading it (and node) first if necessary.
+
+set -eu
+
+NODE_DIR="$HOME/.cache/tailscale-node"
+read -r YARN_REV < "$(dirname "$0")/yarn.rev"
+YARN_DIR="$HOME/.cache/tailscale-yarn"
+# This works for linux and darwin, which is sufficient
+# (we do not build for other targets).
+OS=$(uname -s | tr A-Z a-z)
+ARCH="$(uname -m)"
+if [ "$ARCH" = "aarch64" ]; then
+    # Go uses the name "arm64".
+    ARCH="arm64"
+elif [ "$ARCH" = "x86_64" ]; then
+    # Go uses the name "amd64".
+    ARCH="amd64"
+fi
+
+install_node() {
+    read -r NODE_REV < "$(dirname "$0")/node.rev"
+    NODE_URL="https://nodejs.org/dist/v${NODE_REV}/node-v${NODE_REV}-${OS}-${ARCH}.tar.gz"
+    install_tool "node" $NODE_REV $NODE_DIR $NODE_URL
+}
+
+install_yarn() {
+    YARN_URL="https://github.com/yarnpkg/yarn/releases/download/v$YARN_REV/yarn-v$YARN_REV.tar.gz"
+    install_tool "yarn" $YARN_REV $YARN_DIR $YARN_URL
+}
+
+install_tool() {
+    TOOL=$1
+    REV=$2
+    TOOLCHAIN=$3
+    URL=$4
+
+    archive="$TOOLCHAIN-$REV.tar.gz"
+    mark="$TOOLCHAIN.extracted"
+    extracted=
+    [ ! -e "$mark" ] || read -r extracted junk <$mark
+
+    if [ "$extracted" = "$REV" ] && [ -e "$TOOLCHAIN/bin/$TOOL" ]; then
+        # Already extracted, continue silently
+        return 0
+    fi
+
+    rm -f "$archive.new" "$TOOLCHAIN.extracted"
+    if [ ! -e "$archive" ]; then
+            log "Need to download $TOOL '$REV'."
+            curl -f -L -o "$archive.new" $URL
+            rm -f "$archive"
+            mv "$archive.new" "$archive"
+    fi
+
+    log "Extracting $TOOL '$REV' into '$TOOLCHAIN'." >&2
+    rm -rf "$TOOLCHAIN"
+    mkdir -p "$TOOLCHAIN"
+    (cd "$TOOLCHAIN" && tar --strip-components=1 -xf "$archive")
+    echo "$REV" >$mark
+}
+
+log() {
+    echo "$@" >&2
+}
+
+if [ "${YARN_REV}" = "SKIP" ] ||
+   [ "${OS}" != "darwin" -a "${OS}" != "linux" ] ||
+   [ "${ARCH}" != "amd64" -a "${ARCH}" != "arm64" ]; then
+    log "Using existing yarn (`which yarn`)."
+    exec yarn "$@"
+fi
+
+install_node
+install_yarn
+
+exec /usr/bin/env PATH="$NODE_DIR/bin:$PATH" "$YARN_DIR/bin/yarn" "$@"

tool/yarn.rev

@@ -0,0 +1 @@
+1.22.19