respect minimum version constraints from package.json

gdf.js

@@ -122,7 +122,7 @@ export class GDF {
 
   get astroSSR() {
     return !!(this.#pj.dependencies?.astro) &&
-           !!(this.#pj.dependencies?.['@astrojs/node'])
+      !!(this.#pj.dependencies?.['@astrojs/node'])
   }
 
   get astroStatic() {
@@ -441,9 +441,33 @@ export class GDF {
 
   // what node version should be used?
   get nodeVersion() {
-    const ltsVersion = '20.11.1'
+    const ltsVersion = '20.15.0'
 
-    return process.version.match(/\d+\.\d+\.\d+/)?.[0] || ltsVersion
+    let version = process.version.match(/\d+\.\d+\.\d+/)?.[0] || ltsVersion
+
+    if (this.#pj.engines?.node) {
+      // determine minimal version from package.json
+      let { node } = this.#pj.engines
+      let minversion = node.match(/\d+(\.\d+(\.\d+)?)?/)?.[0].split('.')
+      if (node.includes('>') && !node.includes("=")) {
+        minversion.push(parseInt(minversion.pop()) + 1)
+      }
+
+      // ensure version is at least the minimum
+      version = version.split('.')
+      for (const i=0; i<version.length; i++) {
+        if (minversion[i] > version[i]) {
+          version = minversion
+          break
+        } else if (minversion[i] < version[i]) {
+          break
+        }
+      }
+
+      version = version.join('.')
+    }
+
+    return version
   }
 
   // what bun version should be used?

test/base/version/.dockerignore

@@ -0,0 +1,6 @@
+/.git
+/node_modules
+.dockerignore
+.env
+Dockerfile
+fly.toml

test/base/version/Dockerfile

@@ -0,0 +1,39 @@
+# syntax = docker/dockerfile:1
+
+# Adjust NODE_VERSION as desired
+ARG NODE_VERSION=100
+FROM node:${NODE_VERSION}-slim as base
+
+LABEL fly_launch_runtime="Node.js"
+
+# Node.js app lives here
+WORKDIR /app
+
+# Set production environment
+ENV NODE_ENV="production"
+
+
+# Throw-away build stage to reduce size of final image
+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
+
+# Install node modules
+COPY --link package-lock.json package.json ./
+RUN npm ci
+
+# Copy application code
+COPY --link . .
+
+
+# Final stage for app image
+FROM base
+
+# Copy built application
+COPY --from=build /app /app
+
+# Start the server by default, this can be overwritten at runtime
+EXPOSE 3000
+CMD [ "npm", "run", "start" ]