install node during the BUILD stage of bun deploys

This prevents failure when build scripts contain the inevitable:

  #!/usr/bin/env node

Doesn't yet seem to be a widespread problem for start scripts.
Bun will intercept the top script, the problem arises when
scripts call scripts.

gdf.js

@@ -236,7 +236,13 @@ export class GDF {
 
   // Packages needed for build stage
   get buildPackages() {
-    const packages = ['node-gyp', 'pkg-config', 'build-essential', this.python]
+    const packages = ['pkg-config', 'build-essential', this.python]
+
+    if (!this.bun) {
+      packages.push('node-gyp')
+    } else if (this.bunNode) {
+      packages.push('ca-certificates', 'curl')
+    }
 
     // https://docs.npmjs.com/cli/v10/configuring-npm/package-json#git-urls-as-dependencies
     if (Object.values(this.#pj.dependencies || {}).some(value => /^git(\+|:|hub:)|^\w+\//.test(value))) {
@@ -256,6 +262,21 @@ export class GDF {
     }
   }
 
+  // Does the build script require node?
+  // This is just an approximation, but too many build scripts actually require node.
+  get bunNode() {
+    if (!this.bun) return false
+
+    const build = this.#pj.scripts?.build
+
+    if (build && fs.existsSync(`node_modules/.bin/${build.split(' ')[0]}`)) {
+      const script = fs.readFileSync(`node_modules/.bin/${build.split(' ')[0]}`, 'utf-8')
+      return /^#!.*node/.test(script)
+    }
+
+    return false
+  }
+
   // packages needed for deploy stage
   get deployPackages() {
     const packages = [...this.options.packages.deploy]
@@ -405,7 +426,7 @@ export class GDF {
 
   // what node version should be used?
   get nodeVersion() {
-    const ltsVersion = '18.16.0'
+    const ltsVersion = '20.11.1'
 
     return process.version.match(/\d+\.\d+\.\d+/)?.[0] || ltsVersion
   }

templates/Dockerfile.ejs

@@ -72,6 +72,12 @@ RUN <% if (options.cache) { %><%= pkg_cache %>
     <% } %><%= pkg_update %> && \
     <%= pkg_install %> <%= buildPackages.join(' ') %>
 
+<% if (bunNode) { -%>
+# Install Node.js
+RUN curl -fsSL https://deb.nodesource.com/setup_<%= nodeVersion.split('.')[0] %>.x | bash - && \
+    apt-get install -y nodejs
+
+<% } -%>
 # Install node modules
 COPY<% if (options.link) { %> --link<% } %> <%= packageFiles.join(' ') %> ./
 RUN <%- buildCache %><%= packagerInstall %>

test/base/bun/Dockerfile

@@ -18,7 +18,7 @@ FROM base as build
 
 # Install packages needed to build node modules
 RUN apt-get update -qq && \
-    apt-get install --no-install-recommends -y build-essential node-gyp pkg-config python-is-python3
+    apt-get install --no-install-recommends -y build-essential pkg-config python-is-python3
 
 # Install node modules
 COPY --link bun.lockb package.json ./

test/base/cache-bun/Dockerfile

@@ -20,7 +20,7 @@ FROM base as build
 RUN --mount=type=cache,id=cache,target=/var/cache/apt \
     --mount=type=cache,id=lib,target=/var/lib/apt \
     apt-get update -qq && \
-    apt-get install --no-install-recommends -y build-essential node-gyp pkg-config python-is-python3
+    apt-get install --no-install-recommends -y build-essential pkg-config python-is-python3
 
 # Install node modules
 COPY --link bun.lockb package.json ./