How can I determine when the last inflation was distributed?

Question

So inflation gets run once a week according to the docs.

My question is how can you tell when the last inflation was run, and subsequently when the next inflation is eligible to be generated.

Also, according to the docs:

The distribution of new lumens is limited to once a week. Inflation is run in response to an inflation operation that anyone can submit to the network.

My guess is that someone already has a script/service that submits the inflation operation to the network every week, so the day/time in the foreseeable future will basically stay consistent? What is the day/time that this occurs/has occurred?

Are lumens distributed immediately after this inflation operation is sent (like, within seconds)?

I've edited this comment to ask questions specifically about determining when the last inflation was generated/distributed, as the existing question What day of the week does the Stellar network pay out inflation? does not explicitly state a day.

Answer 1

Given the current set of tools in our ecosystem (and lack of analytical systems) the easiest way to programatically determine when the last inflation was distributed is using Horizon server. You can do it two ways:

• If you want to be notified when inflation is executed you can stream all the operations and call a function when operation type is equal to inflation.
• If you want to get the last time when inflation was run, you can iterate pages of operations from the newest operations and stop when you achieve operation with a type equal to inflation.

Below you can find code snippets in Node.js for each of the methods above.

Notify next inflation

let StellarSdk = require('stellar-sdk');
let horizon = new StellarSdk.Server("https://horizon.stellar.org");

let stopStreaming = horizon.operations().cursor("now").stream({
  onmessage: operation => {
    if (operation.type == "inflation") {
      console.log(`Last inflation distributed at ${operation.created_at} (${operation.id})`);
      stopStreaming();
    } else {
      console.log(`Not inflation ${operation.id}`);
    }
  }
});

Last time inflation distributed

let StellarSdk = require('stellar-sdk');
let horizon = new StellarSdk.Server("https://horizon.stellar.org");

function processResults(results) {
  for (let operation of results.records) {
    if (operation.type == "inflation") {
      console.log(`Last inflation distributed at ${operation.created_at} (${operation.id})`);
      return;
    } else {
      console.log(`Not inflation ${operation.id}`);
    }
  }

  setImmediate(() => results.next().then(processResults));
}

horizon.operations().order("desc").limit(200).call().then(processResults);

Hopefully we will see analytical tools (or block explorers will start displaying this data) in a near future that will give answers to similar questions without writing a code.