This is just a sample Azure function

sampleFunction.js

const mongoose = require('mongoose').set('debug', process.env.NODE_ENV !== 'production');
const SampleService = require('./sampleService');
const DatabaseCache = require('./databaseCache');

// The time-to-live in seconds for each cache entry.
const cacheTtl = process.env.CACHE_TTL || 3600;
// The cache must live in global scope so it remains in memory between invocations.
let databaseCache = new DatabaseCache(cacheTtl);

const sampleFunctionHandler = async (context, req) => {
    let databaseService;
    
    // Boilerplate section ------------------------------
    // First we fetch secrets by parsing the request. This section is intentionally removed to simplify.
    
    // The dbHost came from secrets above.
    const cacheName = `${dbHost}`;
    
    // In some functions, the following code may have to get two connections instead of just one.
    
    // Check if a cache exists.
    const cacheExists = databaseCache.cacheExists(cacheName);
    if (cacheExists) {
        // We already have the databaseService cached, so this will not create a new one.
        databaseService = databaseCache.getService(cacheName, {});
    } else {
        // This will create a new cache entry with a new DatabaseService.
        databaseService = databaseCache.getCache(cacheName, {
            dbUri,
            dbName,
            databaseOpts,
        });
    }
    
    // End of Boilerplate section ------------------------------
    
    try {
        // Use the connection to query the database via a service.
        const conn = await databaseService.getConnection(context);
        const sampleService = new SampleService(conn);
        const result = await sampleService.findById(someIdFromRequest);
    } catch (error) {
        // Return an error response.
        context.res.status = 500;
        context.res.body = error.message;
        return context.res;
    }
    
    // Return a response.
    context.res.status = 200;
    context.res.body = result;
    return context.res;
};

module.exports = sampleFunctionHandler;