ephemeral.js

/*

  Files in directories in "ephemeral" will be deleted 
  when they're older than the name specified by the directory

  For example:
  - Files in directory "min5" won't be older than 5 minutes
  - Files in directory "min15" won't be older than 15 minutes
  - Files in directory "day30" won't be older than 30 days

  Time is fuzzy because the cron runs every 1min, so a file might
  last 6 minutes in a directory called "min5"

  No need to worry about the Node app always being on, as soon as 
  it starts back up, it will clear the older files within 1 min

*/

import { promises as fs } from "fs";
import path from "upath";
import cron from "node-cron";
import basedir from "#root/server-lib/basedir.js";

const targetDirectory = path.join(basedir, "ephemeral");

/**
 * Sets up a single cron job that runs every 5 minutes for each sub-directory in the base directory,
 * deleting files older than the age limit implied by the sub-directory name.
 */
async function setupCronJobForSubDirs(baseDir) {
  cron.schedule('* * * * *', async () => {
    try {
      const dirs = await fs.readdir(baseDir);
      for (const dir of dirs) {
        const dirPath = path.join(baseDir, dir);
        const ageLimit = parseDirNameToAgeLimit(dir);
        if (dirPath.includes("/ephemeral/") && ageLimit !== null) {
          await deleteOldFilesInDir(dirPath, ageLimit);
        }
      }
    } catch (error) {
      console.error(`Error in cron job: ${error}`);
    }
  });

  console.log(`Cron job scheduled to run every 1 minute for directories in ${baseDir}`);
}

/**
 * Converts a directory name to an age limit in milliseconds.
 */
function parseDirNameToAgeLimit(dirName) {
  const match = dirName.match(/(min|hour|day)s?(\d+)/);
  if (!match) return null;

  const [, unit, value] = match;
  let ageLimit;

  switch (unit) {
    case 'min':
      ageLimit = parseInt(value, 10) * 60 * 1000; // milliseconds
      break;
    case 'hour':
      ageLimit = parseInt(value, 10) * 60 * 60 * 1000; // milliseconds
      break;
    case 'day':
      ageLimit = parseInt(value, 10) * 24 * 60 * 60 * 1000; // milliseconds
      break;
    default:
      return null;
  }

  return ageLimit;
}

/**
 * Deletes files older than a specified age limit within a directory.
 */
async function deleteOldFilesInDir(dirPath, ageLimit) {
  try {
    const files = await fs.readdir(dirPath);
    const now = new Date();

    for (const file of files) {
      if (file.includes(".gitkeep")) {
        return;
      }

      const filePath = path.join(dirPath, file);
      const fileStats = await fs.stat(filePath);
      const fileAge = now - new Date(fileStats.mtime);

      if (fileAge > ageLimit) {
        await fs.unlink(filePath);
        console.log(`Deleted: ${filePath}`);
      }
    }
  } catch (error) {
    console.error(`Error in deleteOldFilesInDir: ${error}`);
  }
}

// Initialize the cron job setup
setupCronJobForSubDirs(targetDirectory);