Adding or deleting data in a file with Cloud Functions - firebase

Question

my idea is to be able to edit files in storage.
This edition consists of adding or deleting file data according to the firebase trigger.
I created a trigger in firebase after obtaining the file with the bucket.file function ("file.txt"). CreateReadStream ()
and I edited the data in the base in the change in the firebase after this I updated the file with the function
bucket.file ("file.txt"). createWriteStream ().
This solution is good when there is 1 trigger, but when there are more than 2 triggers, the data does not keep correctly why the file is overwritten with the data it had before.
Example
this is the content of file.txt
This text is an example
and executed 2 triggers
the 2 activators get the file at the same time and the first trigger adds data and overwrites the file with this message
this text is an example
and this file was edited with the first trigger
and the second activator erases data and overwrites the file with this message
this text
When the triggers are finished, the file has "this text"
but this file must have
this text
and this file was edited with the first trigger
Someone help me.
exports.createData = functions.database.ref('data/{id}/summary/status').onCreate((data, context) => {
let status = data._data;
return Promise.all([ admin.database().ref('data/' + context.params.id + '/summary/entityUrl').once('value', (snapshot) => {
let entityUrl = snapshot.val();
if (isDataValid(status))
return addDataFile(entityUrl) ;
return;
}) ]);
})
function addDataFile(entityUrl){
return Promise.all([ returnFile("txt",() => {
dataFile.splice(dataFile.length - 1, 0, `new data ${entityUrl}`)
updateFileStorage("txt", dataFile.join('\n'));
}) ]);
}
function returnFile(extension, callback) {
let respData = "";
if (dataFile == null ){
return bucket.file(FileUrl + extension).createReadStream()
.on('data', (chunk) => {
respData += chunk;
})
.on('end', () => {
dataFile = respData.split('\n');
callback();
})
.on('error', (error) => {
console.log("Error en lectura")
return returnFile(extension, callback);
})
}
else callback();
return;
}
function updateFileStorage(extension,data, trys ){
trys = typeof trys !== 'undefined' ? trys : 0;
if(trys>6)
return;
var s = new Readable();
s._read = function noop() { };
s.push(data);
s.push(null);
return s.pipe(bucket.file(FileUrl + extension).createWriteStream())
.on('finish', function () {
//console.log("File updated");
return;
})
.on('error', function (err) {
console.log("Error de Escritura");
return setTimeout(() => {
return updateFileStorage(extension, data, trys + 1)
}, 250);
})
}