Get process with their inotify handles and watches counts

get-process-with-intofiy-handles.js

// based on https://unix.stackexchange.com/questions/15509/whos-consuming-my-inotify-resources/426001#426001
const fs = require('fs');
const { promisify } = require('util');

const readdirAsync = promisify(fs.readdir);
const readFileAsync = promisify(fs.readFile);
const readlinkAsync = promisify(fs.readlink);

(async function () {
    if (process.platform !== 'linux') {
      console.log('This script useful only on linux')
      return;
    }

    const procEntries = await readdirAsync('/proc');
    const pids = procEntries.filter(e => e.match(/\d+/));
    const intofiyPidMap = {};
    await Promise.all(
      pids.map(async pid => {
        try {
          const procFds = await readdirAsync(`/proc/${pid}/fd`);
          const procFdsWithLinks = await Promise.all(
            procFds.map(async fd => ({
              fd,
              link: await readlinkAsync(`/proc/${pid}/fd/${fd}`),
            })),
          );

          const intofiyFds = procFdsWithLinks.filter(
            ({ link }) => link && link.includes('inotify'),
          );

          const allPidInfo = await Promise.all(
            intofiyFds.map(async ifd => {
              try {
                const fdinfo = (await readFileAsync(
                  `/proc/${pid}/fdinfo/${ifd.fd}`,
                )).toString();
                const fdinfoIntofiyFdsCount = (fdinfo.match(/inotify/g) || [])
                  .length;

                return {
                  ...ifd,
                  pid,
                  fdinfoIntofiyFdsCount,
                };
              } catch (e) {
                console.log(
                  `Error reading /proc/${pid}/fdinfo/${ifd.fd} - ${e.message}`,
                );
                return null;
              }
            }),
          );

          intofiyPidMap[pid] = allPidInfo;
        } catch (e) {
          // I don't care about permission denined, probably pid not owned by user
          // console.log(`Error reading /proc/${pid}/fd - ${e.message}`);
        }
      }),
    );

    const stats = Object.keys(intofiyPidMap)
      .filter(k => intofiyPidMap[k].length > 0)
      .map(k => {
        const pid = intofiyPidMap[k][0].pid;
        const handlesCount = intofiyPidMap[k].length;
        const watchesCount = intofiyPidMap[k].reduce(
          (acc, fdInfo) => acc + fdInfo.fdinfoIntofiyFdsCount,
          0,
        );

        return {
          pid,
          handlesCount,
          watchesCount,
        };
      })
      .sort((a, b) => a.watchesCount - b.watchesCount);

    stats.forEach(async stat => {
      const cmdline = (await readFileAsync(
        `/proc/${stat.pid}/cmdline`,
      )).toString();

      const cwd = await readlinkAsync(`/proc/${stat.pid}/cwd`);

      console.log(`PID ${stat.pid} handles: ${stat.handlesCount} watches: ${stat.watchesCount} cmd: "${cmdline}" cwd: ${cwd}`);
    });

    console.log('Count inotify fds in /proc done:', stats.length);
})();