the result of if() compare condition is wrong

[klom303]

etcd3 Version: 0.2.13 etcd Version: 3.3.12 nodejs Version: 10.15.3 OS: Ubuntu 18.04

In a transaction, if() support compare condition. In my case, I want to compare Value to a number, but the result is wrong.

const Etcd3 = require('etcd3').Etcd3;

const client = new Etcd3({hosts: ['192.168.142.135:2379']});

(async () => {
  const key = 'test_key';
  const oldValue = 9;
  const newValue = 10;
  await client.put(key).value(oldValue).exec();
  const response = await client.if(key, 'Value', '<', newValue).then(client.put(key).value(newValue)).commit();
  console.log(response);
})();

response

{ responses: [],
  header:
   { cluster_id: '18011104697467366872',
     member_id: '6460912315094810421',
     revision: '583',
     raft_term: '7' },
  succeeded: false }

It seems before the compare step, the number parameter was converted to a string. Is this the correct usage ?

[connor4312]

How is your number being stored? ETcd uses the byte sort order to compare the values. So the string "100" is less than "7", since the byte for the character 1 comes before 7.

If this is the problem, I'd suggest storing your numbers encoded as big endian integers to make sure the sort is correct.

function store(myValue) {
  const buf = Buffer.alloc(4);
  buf.writeUInt32BE(myValue);
  return client.put(key).value(buf);
}

async function read() {
  const buf = await client.get(key).buffer();
  return buf === null ? null : buf.readUint32BE();
}