Using durable functions in azure function app with mongodb - node.js

Question

I have a mongoDB which contains the time where in my durable function should run (e.g. 8:00, 9:01, 10:20). Now I have my Orchestrator code below, nothing works inside the mongoClient.connect. Why???
const df = require("durable-functions");
const moment = require("moment");
const mongoClient = require("mongodb").MongoClient;
module.exports = df.orchestrator(function*(context) {
context.log("Getting time schedules in DB");
var timeSched = [];
var dbName = <dbName>;
var collectionName = <collectionName>;
var query = {id: "1"};
try{
mongoClient.connect(<mongoDB_connection_string>,{useNewUrlParser: true, authSource: dbName}, function (err, client) {
//Anything inside this does not log or work
if(err){
context.log(`Error occurred while connecting to DB ${err}`)
return context.done();
}else{
context.log('MongoClient connected to DB');
}
var collection = client.db(dbName).collection(collectionName);
collection.find(query).toArray(function(err, result) {
if (err) throw err;
for(let i = 0; i < result.length; i++){
timeSched.push(result[i].time); //e.g.8:00
}
client.close();
//This should log [8:00,9:01,10:01] but it does not log
context.log(timeSched);
context.done();
});
});
//This logs 0
context.log(timeSched.length);
for (let j = 0; j < timeSched.length; j++) {
const deadline = moment.utc(context.df.currentUtcDateTime).add(3, 'minutes');
yield context.df.createTimer(deadline.toDate());
yield context.df.callActivity("ActivityFunction",timeSched[j]);
}
context.done();
}catch(e){
context.log(`Error ${e}`);
context.done();
}
});

Answer 1

Try the code below to check if you can connect to DB first. Use console.log instead of context.log.
const df = require("durable-functions");
const mongoClient = require("mongodb").MongoClient;
module.exports = df.orchestrator(function*(context) {
var mongoClient = require("mongodb").MongoClient;
mongoClient.connect(
"mongodb://tonytest:78jst6Mh****.documents.azure.com:10255/?ssl=true",
function(err, client) {
if (err) {
console.log(`Error occurred while connecting to DB ${err}`);
return context.done();
} else {
console.log("MongoClient connected to DB");
}
client.close();
}
);
});
Try with console.log(timeSched); to output timeSched. Besides, when you execute console.log(timeSched.length);, timeSched hasn't been granted value. That's why you got 0;