Refactor site generation into a modular content pipeline

vite.config.js

@@ -2,6 +2,8 @@ import fs from 'node:fs'
 import { spawn } from 'node:child_process'
 import path from 'node:path'
 import { defineConfig } from 'vite'
+import { createRegenerationQueue } from './dev-reload.js'
+import { contentDirectories, contentSources, generatedRoot } from './site.config.js'
 
 function generatedPages(directory) {
   const inputs = {}
@@ -9,10 +11,10 @@ function generatedPages(directory) {
     const filePath = path.join(directory, entry.name)
     if (entry.isDirectory()) Object.assign(inputs, generatedPages(filePath))
     else if (entry.name === 'index.html') {
-      const relativePath = path.relative('.generated', filePath)
+      const relativePath = path.relative(generatedRoot, filePath)
       const key = relativePath.endsWith('/index.html') ? relativePath.slice(0, -'/index.html'.length) : relativePath
       inputs[key] = path.resolve(filePath)
-    } else if (entry.name === '404.html' && directory === '.generated') {
+    } else if (entry.name === '404.html' && directory === generatedRoot) {
       inputs['404'] = path.resolve(filePath)
     }
   }
@@ -27,7 +29,7 @@ function copyGeneratedFiles() {
       const dist = path.resolve('dist')
       if (!fs.existsSync(dist)) return
       for (const file of files) {
-        const source = path.resolve('.generated', file)
+        const source = path.resolve(generatedRoot, file)
         if (fs.existsSync(source)) fs.copyFileSync(source, path.join(dist, file))
       }
     },
@@ -35,57 +37,34 @@ function copyGeneratedFiles() {
 }
 
 function contentGenerator() {
-  let timer
-  let generator
-  let rerun = false
-
-  const generate = (server) => {
-    if (generator) {
-      rerun = true
-      return
-    }
-
-    generator = spawn(process.execPath, ['generator.js', '--drafts'], { stdio: 'inherit' })
-    generator.on('error', (error) => {
-      console.error(`Content generation failed: ${error.message}`)
-    })
-    generator.on('close', (code) => {
-      generator = undefined
-      if (code === 0) server.ws.send({ type: 'full-reload' })
-      if (rerun) {
-        rerun = false
-        generate(server)
-      }
-    })
-  }
-
   return {
     name: 'content-generator',
     configureServer(server) {
-      const sources = [
-        path.resolve('notes'),
-        path.resolve('posts'),
-        path.resolve('README.md'),
-        path.resolve('THIRD_PARTY_LICENSES.md'),
-        path.resolve('external.json'),
-        path.resolve('generator.js'),
-        path.resolve('html.js'),
-      ]
-      server.watcher.add(sources)
+      const queue = createRegenerationQueue({
+        generate: () => new Promise((resolve, reject) => {
+          const child = spawn(process.execPath, ['generator.js', '--drafts'], { stdio: 'inherit' })
+          child.once('error', reject)
+          child.once('close', (code) => code === 0 ? resolve() : reject(new Error(`exit ${code ?? 'unknown'}`)))
+        }),
+        onSuccess: () => server.ws.send({ type: 'full-reload' }),
+        onError: (error) => {
+          console.error(`Content generation failed: ${error.message}`)
+          server.ws.send({
+            type: 'error',
+            err: { message: `Content generation failed (${error.message}). Check the terminal for details.`, stack: '' },
+          })
+        },
+      })
+      const sources = new Set(contentSources.map((source) => path.resolve(source)))
+      server.watcher.add([...sources])
+      server.httpServer?.once('close', () => queue.close())
       server.watcher.on('all', (event, file) => {
         if (!['add', 'change', 'unlink'].includes(event)) return
         const isMarkdown =
           file.endsWith('.md') &&
-          (file.startsWith(`${path.resolve('notes')}/`) || file.startsWith(`${path.resolve('posts')}/`))
-        const isExternal = file === path.resolve('external.json')
-        const isStandaloneMarkdown =
-          file === path.resolve('README.md') || file === path.resolve('THIRD_PARTY_LICENSES.md')
-        const isGenerator = file === path.resolve('generator.js') || file === path.resolve('html.js')
-        if (!isMarkdown && !isStandaloneMarkdown && !isExternal && !isGenerator) return
-        clearTimeout(timer)
-        timer = setTimeout(() => {
-          generate(server)
-        }, 100)
+          contentDirectories.some((dir) => file.startsWith(`${path.resolve(dir)}/`))
+        if (!isMarkdown && !sources.has(file)) return
+        queue.request()
       })
     },
   }
@@ -93,7 +72,7 @@ function contentGenerator() {
 
 export default defineConfig({
   plugins: [contentGenerator(), copyGeneratedFiles()],
-  root: '.generated',
+  root: generatedRoot,
   publicDir: '../public',
   resolve: {
     alias: {
@@ -102,14 +81,14 @@ export default defineConfig({
   },
   server: {
     watch: {
-      ignored: ['**/.generated/**'],
+      ignored: [`**/${generatedRoot}/**`],
     },
   },
   build: {
     outDir: path.resolve('dist'),
     emptyOutDir: true,
     rollupOptions: {
-      input: generatedPages('.generated'),
+      input: generatedPages(generatedRoot),
     },
   },
 })