core foundation for alpha Next.js build plugin with config requirements

Author: lindsaylevine

.gitignore

@@ -0,0 +1 @@
+node_modules/

index.js

@@ -0,0 +1,92 @@
+const fs = require('fs');
+const { existsSync, readFileSync } = require('fs');
+const path = require('path');
+const { appendFile, readdir } = require('fs').promises;
+const { listFrameworks } = require('@netlify/framework-info');
+const nextOnNetlify = require('next-on-netlify');
+const { PHASE_PRODUCTION_BUILD } = require('next/constants');
+const { default: loadConfig } = require('next/dist/next-server/server/config');
+const makeDir = require('make-dir');
+const cpx = require('cpx');
+
+const _isNextProject = async () => {
+  const frameworks = await listFrameworks();
+  return !!frameworks.find(({ name }) => name === 'next');
+};
+
+// TO-DO:
+// - add try catches and error handling
+// - edge cases:
+//    - making sure functions_dir doesnt have a custom function named something that NoN could generate
+
+// * Helpful Plugin Context *
+// - Between the prebuild and build steps, the project's build command is run
+// - Between the build and postbuild steps, any functions are bundled
+
+module.exports = {
+  async onPreBuild({ constants, netlifyConfig, utils }) {
+    const isNextProject = await _isNextProject();
+    const { build } = netlifyConfig;
+    const { failBuild } = utils.build;
+
+    if (isNextProject) {
+      // TO-DO: read scripts from package.json and test this there
+      const isStaticExport = build && build.command && build.command.includes('next export');
+      if (isStaticExport) {
+        failBuild(`** Static HTML export next.js projects do not require this plugin **`);
+      }
+
+      // TO-DO: read dependencies from package.json
+      // fail build if next-on-netlify is already installed or in a script?
+
+      const hasFunctionsDirectorySet = build && netlifyConfig.functions;
+      if (!hasFunctionsDirectorySet) {
+        failBuild
+      }
+
+      if (existsSync('next.config.js')) {
+        // If the next config exists, fail build if target isnt in acceptableTargets
+        const acceptableTargets = ['serverless', 'experimental-serverless-trace'];
+        const nextConfig = loadConfig(PHASE_PRODUCTION_BUILD, path.resolve('.'));
+        const isValidTarget = acceptableTargets.includes(nextConfig.target);
+        if (!isValidTarget) {
+          failBuild(`next.config.js must be one of: ${acceptableTargets.join(', ')}`);
+        }
+      } else {
+        // Create the next config file with target set to serverless by default
+        const nextConfig = `
+          module.exports = {
+            target: 'serverless'
+          }
+        `;
+        await appendFile('next.config.js', nextConfig);
+        console.log(`** Adding next.config.js with target set to 'serverless' **`);
+      }
+    } else {
+      failBuild(`This application does not use Next.js.`);
+    }
+  },
+  async onBuild({ constants }) {
+    const isNextProject = await _isNextProject();
+
+    if (isNextProject) {
+      console.log(`** Running Next on Netlify package **`);
+      nextOnNetlify();
+
+      // Next-on-netlify puts its files into out_functions and out_publish
+      // Copy files from next-on-netlify's output to the right functions/publish dirs
+      const { FUNCTIONS_DIST, PUBLISH_DIR } = constants;
+      await makeDir(FUNCTIONS_DIST);
+      await makeDir(PUBLISH_DIR);
+      cpx.copySync('out_functions/**/*', FUNCTIONS_DIST);
+      cpx.copySync('out_publish/**/*', PUBLISH_DIR);
+    }
+  },
+  async onPostBuild({ constants }) {
+    const { FUNCTIONS_DIST, PUBLISH_DIR } = constants;
+    await makeDir(FUNCTIONS_DIST);
+    await makeDir(PUBLISH_DIR);
+    cpx.copySync('out_functions/**/*', FUNCTIONS_DIST);
+    cpx.copySync('out_publish/**/*', PUBLISH_DIR);
+  }
+}

manifest.yml

@@ -0,0 +1 @@
+name: netlify-plugin-nextjs