Earth Engine dataset latency calculator

ee_dataset_latency_calculator.js

// #############################################################################
// ### INPUTS ###
// #############################################################################

var COL_ID = ee.ImageCollection("COPERNICUS/S1_GRD");
var PERIOD = 0.1;  // Today to PERIOD months prior

// #############################################################################


function calcLatency(img) {
  var version = img.get('system:version');
  var ingest = ee.Date(ee.Number(version).divide(1000));
  var observe = img.date();
  var latency = ingest.difference(observe, 'hours');
  return img.set('latency', latency);
}

var col = ee.ImageCollection(COL_ID);
var today = ee.Date(Date.now());

col = col.filterDate(today.advance(-PERIOD, 'months'), today)
  .map(calcLatency);

var meanLatency = col.reduceColumns({
    reducer: ee.Reducer.mean(),
    selectors: ['latency']
}).get('mean');

print('Mean latency (hours) for last ' + PERIOD + ' months:',
      meanLatency);