NodeJS can't await MySQL database promise, but awaits other promises - mysql

Question

let static_times_generate = async (static_file_path) => {
//Import MySQL database pool connection:
const db = require('../database_pool.js');
const Promise_pool = db.promise();
//Import Static Text file dependencies:
const { readFile } = require('fs/promises') , stop_times = static_file_path+'/stop_times.txt', trips = static_file_path+'/trips.txt';
let trip_data = (await readFile(trips,'utf8')).split('\n').slice(1,2);
let stop_times_data = (await readFile(stop_times,'utf8')).split('\n').slice(1,-1);
trip_data.forEach(trip_line => {
const t_array = trip_line.split(',');
stop_times_data.forEach(st_line =>{
const st_array = st_line.split(',');
if(st_array[0] == t_array[2]){
if(t_array[1] == 'SundaySum'){ t_array[1] = 'Sunday' }
else if(t_array[1] == 'SaturdaySum'){ t_array[1] = 'Saturday' }
//Here is the issue
await Promise_pool.execute(`INSERT INTO static_times (1, 2, 3, 4, 5, 6, 7) VALUES (?,?,?,?,?,?,?)`
,[elm1,elm2,elm3,elm4,elm5,elm6,elm7] )
}
});
});
console.log("COMPLETED!")
}
static_times_generate('./mysql_table_generators/STATIC_FILES'); //This is how i'm calling the function
I read files and push certain data into a MySQL database, I'm using node mysql2 for this.
let trip_data = (await readFile(trips,'utf8')).split('\n').slice(1,2);
let stop_times_data = (await readFile(stop_times,'utf8')).split('\n').slice(1,-1);
The readFile promises are being awaited just fine, but when it comes to the Promise_pool query, it's giving the error:
await Promise_pool.execute(`INSERT INTO static_times (routeId, serviceId, tripId, stopId, arrivalTime, orientation, tripHeadsign) VALUES (?,?,?,?,?,?,?)`
^^^^^
SyntaxError: await is only valid in async function
at wrapSafe (internal/modules/cjs/loader.js:979:16)
at Module._compile (internal/modules/cjs/loader.js:1027:27)
at Object.Module._extensions..js (internal/modules/cjs/loader.js:1092:10)
at Module.load (internal/modules/cjs/loader.js:928:32)
at Function.Module._load (internal/modules/cjs/loader.js:769:14)
at Function.executeUserEntryPoint [as runMain] (internal/modules/run_main.js:72:12)
at internal/main/run_main_module.js:17:47
I've done this kind of await in other files of my code, and it worked, Why isn't it recognizing that the await is wrapped in an async function? (I've also tried the await db.execute method, without using the db.promise() prototype)
This is my database_pool.js file
const mysql = require('mysql2');
const db_pool = mysql.createPool({
host: 'localhost',
user: 'root',
password: '',
database: 'drt_sms_db',
multipleStatements: true
});
module.exports = db_pool;
*** Yes I know I don't need the await, however i'm inserting 1 million rows into my database, so I get a MySQL ETIMEOUT error. await is my only option at this point.

Answer 1

The scope of your await call is restricted to the forEach callback function. If you want to use await you can add async to the forEach callback like this:
stop_times_data.forEach(async (st_line) => {
await doSomething();
}
That being said, the callback function here does not actually wait for the promise to finish since forEach accepts only synchronous functions. Have a look here for more details. If you need to wait for one request to finish before sending another one you should use a for loop instead.