Using RateLimiterPostgres + knex.js yields wrong data in db

[noamackerman-monday]

Hi,
When using the RateLimiterPostgres + knex.js, i'm seeing wrong results written to the db when the points limit is exceeded.

Code:
const {RateLimiterPostgres} = require('rate-limiter-flexible');
let options = { storeClient: connection, storeType: knex, points: 2, duration: 0, blockDuration: 60 * 60 * 24 * 365, tableName: 'downloads_rate_limiter', keyPrefix: 'downloadsrl', inmemoryBlockOnConsumed: 2, inmemoryBlockDuration: 60 * 60 * 24 * 365, tableCreated: true };

const rateLimiter = new RateLimiterPostgres(options);

app.get('/hello', async (req, res) => {
try { await rateLimiter.consume(obj, 1); doSomeOperation(); } catch (error) { if (error instanceof Error) { // Some Postgres error // Never happen ifinsuranceLimiter set up res.writeHead(500) } else { // Can't consume res.writeHead(429); } res.end(error.toString()) }
});

Now let's say i'm calling the 'hello' endpoint 3 times and looking the at points column in the db. After the first 2 times i will see the value 2, which is expected, but at the 3rd time and on i will start to see some random value, jumping from 2 to 6, then to 9 and 12 etc.

Can you please help me understand what is the reason for this behaviour? Seems like a bug.

Thanks!
Noam

[animir]

@noamackerman-monday Hi, it looks like a bug. I am quite busy now, I am going to look at it over the next weekend. If you need a fix earlier, you can try search a bug from this block of code

node-rate-limiter-flexible/lib/RateLimiterStoreAbstract.js

Line 65 in 9847947

if (this.blockDuration > 0 && res.consumedPoints <= (this.points + changedPoints)) {

[animir]

@noamackerman-monday I fixed this bug and published patched 2.1.15 version to npm.

Why do you need to know consumedPoints after block, btw? Just curious about your use case.

[noamackerman-monday]

@animir Amazing thanks!
I don't need to know it actually, just did some basic testing to see that it works as expected and found it.