Serverless target specific files not available during plugin execution

[asterikx]

I'm trying to write a plugin (based on this code from serverless-next.js) to generate (serverless) handler code for AWS Lambda@Edge.
This plugin needs to read from serverless target-specific files, in particular from the prerender-manifest.json manifest file.
However, these files seem not yet available during the webpack execution. Does anyone know how/when these can be accessed?

To give a rough idea, usage should look like:

// next.config.js

const withPlugins = require('next-compose-plugins');
const images = require('next-images');
const lambdaEdge = require('./lambda-edge-plugin');

const plugins = [lambdaEdge, images];

const nextConfig = {
  distDir: process.env.BUILD_DIR || '.next',
  target: 'serverless',
};

module.exports = withPlugins(plugins, nextConfig);

For this, I created the following NextLambdaEdgePlugin webpack plugin:

class NextLambdaEdgePlugin {
  constructor(nextConfig, options) {
    const { config: { distDir } } = nextConfig;
    this.nextDistDir = distDir;
  }

  apply(compiler) {
    const done = (stats) => {
      const { nextDistDir } = this;

      // return generateHanlderCode(...);

      fse.readdir(nextDistDir, (err, files) => {
        files.forEach((file) => {
          console.log(file);
        });
      });
      return Promise.resolve();
    };

    compiler.hooks.done.tapPromise('NextLambdaEdgePlugin', done);
  }
}

This prints:

build-manifest.json
cache
react-loadable-manifest.json
routes-manifest.json
serverless
static

What I need during plugin execution is:

BUILD_ID
build-manifest.json
cache
export-marker.json
prerender-manifest.json
react-loadable-manifest.json
routes-manifest.json
serverless
static

The serverless target-specific files are present after next build but not yet during the execution of the plugin. Is there any chance I can access them from the plugin?

[timneutkens]

This is expected, you can't access build artifacts in this way.

[asterikx]

@timneutkens thanks for the reply.

This is expected, you can't access build artifacts in this way.

Does this mean that it is not possible to access build artifacts from plugins at all?

After all, my plugin lists all build artifacts, except the serverless target artifacts. Also, the @next/bundle-analyzer (which uses webpack-bundle-analyzer) runs on the final bundle.

What is the recommended way to execute post-build actions using the final build output (preferably as plugins)?

Thanks