gatsby-plugin-sharp/gatsby-worker.js

Wrapper of the Sharp image manipulation library for Gatsby plugins

"use strict";

const path = require(`path`);
const queue = require(`async/queue`);
const {
  cpuCoreCount
} = require(`gatsby-core-utils/cpu-core-count`);
const {
  processFile
} = require(`./process-file`);
exports.IMAGE_PROCESSING_JOB_NAME = `IMAGE_PROCESSING`;

/** @typedef {import('./process-file').TransformArgs} TransformArgs */

/**
 * @typedef WorkerInput
 * @property {string} contentDigest
 * @property {{outputPath: string, args: TransformArgs[]}} operations
 * @property {object} pluginOptions
 */

/**
 * the queue concurrency is 1 as we only want to transform 1 file at a time.
 * @param {(job: WorkerInput, callback: Function) => undefined} task
 */
const q = queue(async ({
  inputPaths,
  outputDir,
  args
}) => processFile(inputPaths[0].path, args.operations.map(operation => {
  return {
    outputPath: path.join(outputDir, operation.outputPath),
    args: operation.args
  };
}), args.pluginOptions),
// When inside query workers, we only want to use the current core
process.env.GATSBY_WORKER_POOL_WORKER ? 1 : Math.max(1, cpuCoreCount() - 1));

/**
 * @param {{inputPaths: string[], outputDir: string, args: WorkerInput}} args
 * @return Promise
 */
exports.IMAGE_PROCESSING = ({
  inputPaths,
  outputDir,
  args
}) => {
  if (args.isLazy) {
    return Promise.resolve();
  }
  return new Promise((resolve, reject) => {
    q.push({
      inputPaths,
      outputDir,
      args
    }, function (err) {
      if (err) {
        return reject(err);
      }
      return resolve();
    });
  });
};