Azure Redis Cache cache.set() Not operable within Promise.then? - node.js

Question

This one has had me spinning my tires for about 2 days now, I'm ready to reach out for help :)
I have a google firebase functions app, running as a middle-ware to an angular SPA. Hoping to avoid some of the pay-by-use cost of Azure SQL, I wanted to implement a caching option for the most common queries.
I thought I knew redis, I've worked with it before. There's a simple enough example on the repo: https://www.npmjs.com/package//redis
Everything works fine, if it is top level.
But the way my application is built, i need the ability to set a cache value from within the .then of a Promise, and when I try to do that, all operation just stops, with no identifiable error logging, or even response from redis. Even in Azure insights, i'm not getting much feed-back, only that the 'set' operation isn't being counted in metrics.
So, just to clarify, this works:
// "cache", the object, set globally
export const testCache = functions.https.onRequest(
async (req: any, res) => {
await cache.connect();
var redisKey = 'testing_global';
var result = await cache.get(redisKey);
await cache.set(redisKey, 'testing new class')
console.log("\nDone");
cache.disconnect();
res.send('done');
})
But, this does not:
import { createClient } from 'redis';
const cache = createClient({
url: "rediss://" + process.env.REDIS_HOST_NAME + ":6380",
password: process.env.REDIS_KEY,
});
export const getValues = functions.https.onRequest(
(req: any, response) => {
cors(req, response, async () => {
response.set('Access-Control-Allow-Origin', origin);
var searchText = req.body['search'];
var offset = req.body['offset'];
var fetch = req.body['fetch'];
var x = req.body['x'];
var y = req.body['y'];
var districts = req.body['districtFilter'];
var sort = req.body['sort'];
if (offset) {
if (!/^\d+$/.test(offset))
throw new Error('bad number');
} else {
offset = 0;
}
if (fetch) {
if (!/^\d+$/.test(fetch))
throw new Error('bad number');
} else {
fetch = 200;
}
if (x) {
if (!/^-?\d+$/.test(x))
throw new Error('bad number');
} else {
x = null;
}
if (y) {
if (!/^-?\d+$/.test(y))
throw new Error('bad number');
} else {
y = null;
}
if (districts && districts.length > 0) {
districts = sanitizeStringArray(districts);
} else {
districts = null;
}
if (sort) {
switch (sort) {
case "scoreAsc":
case "scoreDesc":
case "priceAsc":
case "priceDesc":
break;
default:
sort = '';
}
}
var redisKey = `get_values_${searchText}_${offset}_${fetch}_${x}_${y}_${districts}_${sort}`;
var cacheResult: any = null;
await cache.connect();
// because I want to end up in the 'else', for testing
cacheResult = await cache.getFromCache('someOtherKey');
if (null !== cacheResult) {
response.send({
"status": "success",
"totalCount": cacheResult.totalCount,
"data": cacheResult.result
});
cache.disconnect();
} else {
var connection = new Connection(sqlConfig);
var totalCount: number = 0;
connection.on('connect', function (err: any) {
// If no error, then good to proceed.
console.log("Connected");
var sql = `EXEC SomeSPC;`;
const sqlRequest = new Request(sql, function (err: any) {
if (err) {
console.log(err);
}
});
const countRequest = new Request(
`EXEC SomeOtherSPC;`
, function (err: any) {
if (err) {
console.log(err);
}
}
)
sqlRequest.connection = connection;
countRequest.connection = connection;
var result: any[] = [];
sqlRequest.on('row', function (columns: any[]) {
var rowResult: any = {};
columns.forEach(function (column: any) {
rowResult[column['metadata']['colName']] = column['value'];
});
result.push(rowResult);
});
sqlRequest.on("requestCompleted", function (rowCount: any, more: any) {
console.log(rowCount + ' rows returned');
connection.execSql(countRequest);
countRequest.on('row', function (columns: any[]) {
totalCount = columns[0]['value'];
});
countRequest.on('requestCompleted', async function (rowCount: any, more: any) {
connection.close();
cacheResult = {
totalCount: totalCount
, result: result
};
// ******************************************************************
// Does Not Work, Just Fails, Without Much to Go On
await cache.set(redisKey, 'in Promise')
response.send({
"status": "success",
"totalCount": totalCount,
"data": result
});
})
});
connection.execSql(sqlRequest);
});
connection.on('infoMessage', infoError);
connection.on('errorMessage', infoError);
connection.on('end', end);
connection.on('debug', debug);
connection.connect();
console.log("Reading rows from the Table...");
}
})
}
)
There's **update- no longer ** a fair amount of psuedo-code here, so please **update- No Need to ** disregard any inconsistent lines. I went ahead and put in the full function, including all the fluff, since trimming the fat seems to make things difficult for others to understand what is being asked.
The sql stuff all works, if i take out the cache.set() everything is fine, but that line, in the result of the Promise, just fails, and I can't figure out why.
I've tried using cache locally and globally, extracting the cache operations to a function, and then to a separate class, and in all cases, i'm getting the same result.
Is there a known reason this wouldn't work?

Answer 1

As far as I can understand, given you didn't provide a reproducible example, your code is binding to the requestCompleted event for the second request only after it runs execSql(): I would suggest moving the binding block before that, otherwise the event may be skipped.