node-fstab/index.js

fstab management with node.js

const fs = require('fs').promises;
const { createReadStream, createWriteStream } = require('fs');
const { exec } = require('child_process');

// Helper function to run a shell command with exec wrapped in a Promise
const runCommand = (command) => {
  return new Promise((resolve, reject) => {
    exec(command, (error, stdout, stderr) => {
      if (error) {
        reject({ error, stderr });
      } else {
        resolve({ stdout, stderr });
      }
    });
  });
};

// Create the mount point if it doesn't exist
const createMountPoint = async (path) => {
  let response = { ok: false };
  try {
    await fs.mkdir(path, { recursive: true });
    response.ok = true;
  } catch (error) {
    if (error.code !== 'EEXIST') {
      response.error = `Failed to create mount point: ${error.message}`;
    } else {
      response.ok = true;
    }
  }
  return response;
};

// Mount the NFS share using a system command with customizable options
const mount = async (server, remotePath, localPath, type = 'cifs', options = 'username=username,password=password') => {
  let response = { ok: false };
  const mountCommand = `sudo mount -t ${type} ${server}:${remotePath} ${localPath} ${options}`.trim();
  try {
    const { stderr } = await runCommand(mountCommand);
    if (stderr) {
      response.error = `Error mounting: ${stderr}`;
    } else {
      response.ok = true;
    }
  } catch (error) {
    response.error = `Failed to mount : ${error.message}`;
  }
  return response;
};

// Execute `mount -a` to remount all filesystems from /etc/fstab
const remountAll = async () => {
  let response = { ok: false };
  try {
    const { stdout, stderr } = await runCommand('mount -a');
    if (stderr) {
      response.error = `Error remounting all filesystems: ${stderr}`;
    } else {
      response.ok = true;
      response.message = stdout.trim() || "Successfully remounted all filesystems from /etc/fstab";
    }
  } catch (error) {
    response.error = `Failed to remount all filesystems: ${error.message}`;
  }
  return response;
};

const remount = async (mountPath) => {
  let response = { ok: false };
  try {
    const { stdout, stderr } = await runCommand(`mount ${mountPath}`);
    const { stdout: daemonStdout, stderr: daemonStderr } = await runCommand(`systemctl daemon-reload`);
    if (stderr) {
        response.error = `Error remounting ${mountPath}: ${stderr}`;
    } else {
        response.ok = true;
        response.message = `Successfully remounted ${mountPath}`;
    }
} catch (failedResponse) {
      // console.error(error)
      response.error = `Failed to remount ${mountPath}: ${failedResponse.error}`;
  }
  return response;
};

const unmount = async (localPath) => {
  let response = { ok: false };
  try {
    const { stdout, stderr } = await runCommand(`sudo umount ${localPath}`);
    if (stderr) {
      response.error = `Error unmounting ${localPath}: ${stderr}`;
    } else {
      response.ok = true;
      response.message = `Successfully unmounted ${localPath}`;
    }
  } catch (error) {
    response.error = `Failed to unmount ${localPath}: ${error.message}`;
  }
  return response;
};

// Check and update /etc/fstab with the NFS entry with customizable options
const update = async (sourceTarget, localPath, mountType = 'cifs', fstabOptions = 'username=username,password=password,rw,iocharset=utf8,file_mode=0777,dir_mode=0777 0 0') => {
  let response = { ok: false };
  const fstabEntry = `${sourceTarget} ${localPath} ${mountType} ${fstabOptions}\n`;

  try {
    // Read the current /etc/fstab file
    const data = await fs.readFile('/etc/fstab', 'utf8');

    // Remove any existing entries with the same localPath
    const updatedData = data
      .split('\n')
      .filter(line => !line.includes(` ${localPath} `))
      .join('\n');

    // Write the modified data back to /etc/fstab without duplicates
    await fs.writeFile('/etc/fstab', updatedData, 'utf8');

    // Append the new fstab entry
    await fs.appendFile('/etc/fstab', fstabEntry);
    response.ok = true;
    response.message = `Successfully updated /etc/fstab with entry for ${localPath}`;
  } catch (error) {
    response.error = `Error updating /etc/fstab: ${error.message}`;
  }
  return response;
};

// Remove an entry from /etc/fstab by mount point
const remove = async (localPath) => {
  let response = { ok: false };
  try {
    const data = await fs.readFile('/etc/fstab', 'utf8');
    const updatedData = data
      .split('\n')
      .filter(line => !line.includes(` ${localPath} `))
      .join('\n');

    if (updatedData !== data) {
      await fs.writeFile('/etc/fstab', updatedData, 'utf8');
      response.ok = true;
    } else {
      response.error = `No entry found for ${localPath} in /etc/fstab.`;
    }
  } catch (error) {
    response.error = `Error removing entry from /etc/fstab: ${error.message}`;
  }
  return response;
};

// fstab mounts
const list = async () => {
  let response = { ok: false, mounts: [] };
  try {
    const data = await fs.readFile('/etc/fstab', 'utf8');
    response.ok = true;
    response.mounts = data
      .split('\n')
      .filter(line => line && !line.startsWith('#')) // Ignore empty lines and comments
      .map(line => {
        const [device, mountPoint, type, options, dump, pass] = line.split(/\s+/);
        return {
          device,        // The device or UUID
          mountPoint,    // The mount point on the local machine
          type,          // Filesystem type
          options: `${options} ${dump} ${pass}`, // Mount options as an array
        };
    })
    .filter(item =>
        !!item.mountPoint &&
        !item.device.includes('/dev/disk') &&
        !item.device.includes('/swap')
    );
  } catch (error) {
    response.error = `Failed to read /etc/fstab: ${error.message}`;
  }
  return response;
};
// Get disk usage information using `df -h` as an array of objects
const getDiskUsage = async () => {
  let response = { ok: false, disks: [] };
  try {
    const { stdout, stderr } = await runCommand('df -h');
    if (stderr) {
      response.error = `Error retrieving disk usage: ${stderr}`;
    } else {
      const lines = stdout.trim().split('\n');
      const headers = lines[0].toLowerCase().split(/\s+/);
      response.ok = true;
      response.disks = lines.slice(1).map(line => {
        const values = line.split(/\s+/);
        return headers.reduce((obj, header, index) => {
          obj[header] = values[index];
          return obj;
        }, {});
      });
    }
  } catch (error) {
    response.error = `Failed to retrieve disk usage: ${error.message}`;
  }
  return response;
};

// Check if a specific local path exists in the disk usage list
const checkDiskPathExists = async (localPath) => {
  let response = { ok: false, exists: false };
  try {
    const diskUsage = await getDiskUsage();
    if (!diskUsage.ok) {
      response.error = `Error retrieving disk usage: ${diskUsage.error}`;
    } else {
      response.exists = diskUsage.disks.some(disk => disk.mounted === localPath);
      response.ok = true;
      response.message = response.exists ? `Path ${localPath} exists` : `Path ${localPath} does not exist`;
    }
  } catch (error) {
    response.error = `Failed to check if path exists: ${error.message}`;
  }
  return response;
};

const writeReadStream = async (readerStream, outputFile) => {
    return new Promise((resolve, reject) => {
        const response = { ok: false }
        const writerStream = createWriteStream(outputFile);
        readerStream.on("error", (error) => {
            response.err = error.toString();
            resolve(response)
        });
        writerStream.on("error", (error) => {
            response.err = error.toString();
            resolve(response)
        });
        writerStream.on("finish", () => {
            response.ok = true;
            resolve(response)
        });
        readerStream.pipe(writerStream);
    });
};

// Export functions
module.exports = {
    createMountPoint,
    mount,
    update,
    remove,
    list,
    remountAll,
    remount,
    unmount,
    getDiskUsage,
    writeReadStream,
    checkDiskPathExists,
    execAsync: runCommand
};