Record Event to Google Sheets via Cloud Function

index.js

// Records a event with a given timestamp to a google sheet

const { google } = require("googleapis");

exports.recordEvent = async (req, res) => {
  if (!crypto.timingSafeEqual(Buffer.from(req.body.key),
                              Buffer.from(process.env.KEY)) {
    return;
  }  
  
  // block on auth + getting the sheets API object
  const auth = await google.auth.getClient({
    scopes: ["https://www.googleapis.com/auth/spreadsheets"]
  });
  const sheets = google.sheets({ version: "v4", auth });
  
  const appendRequest = {
    spreadsheetId: process.env.SPREADSHEET_ID,
    range: process.env.RANGE,
    valueInputOption: 'RAW',
    resource: {
      values: [[new Date().toISOString(), req.body.event]],
    }
  };
  
  await new Promise((resolve, reject) => {
    sheets.spreadsheets.values.append(appendRequest, (err, resp) => {
      if (err) {
        console.error(err);
        reject();
      }    
      console.log(JSON.stringify(resp, null, 2));
      resolve();
    });
  });
};