CODEWITHSUNDEEP
node.jsvariablescachingtimestamp
seref
seref

Reputation: 571

Save value out of nodejs server

Is there a way where I can save a timestamp out of my application / object, so when I restart the nodeserver I can get that value?

I need this for my cronjob. I need to save the last synching even though I restart the server.

Upvotes: 1

Views: 670

Answers (2)

Indikator
Indikator

Reputation: 73

When a process dies, all data stored in its working memory (such as variables and functions) die with it. I recently wrote an npm package cashola that makes it easier to store this data across process restarts.

You can run this example script twice and see how the print statements differ each time.

import { rememberSync } from 'cashola';

const myState = rememberSync('timestamp-example');

console.log('Before:', myState);
// First run: {}
// Second run: { <timeString1>: 'hi! }
myState[new Date.getTime().toString()] = 'hi!';
console.log('After:', myState);
// First run: { <timeString1>: 'hi! }
// Second run: { <timeString1>: 'hi!, <timeString2>: 'hi! }

Upvotes: 0

O. Jones
O. Jones

Reputation: 108796

There are all sorts of ways to save this sort of information so you can load it when you restart your node process. One is to write it to a file in your file system, then read it when you start your program.

To write the current timestamp to a file do this.

const fs = require('fs')
...
fs.writeFile('timestamp.txt', Date.now().toString(), err => {console.error(err)})

To read it do this.

const fs = require('fs')
...
const timestamp = Number(fs.readFileSync('timestamp.txt'))

Obviously there's more programming to do to put the file in the correct directory, to handle errors, and to cope with the case where you attempt to read the file before writing it. But that's the idea.

You can also store it in some kind of database. But this should do you for now. Unless you're using a system like Heroku where the files don't always get saved from run to run.

Upvotes: 1

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