Statistics Library Documentation

This JavaScript library provides methods for collecting and aggregating numerical data, useful for analytics, charts, and real-time metrics.

Integration into your development project

Add/Include service/statistics/statistics.mak in your project's makefile.
Edit config.json and add API announcement and service files:

{
  "javascript": {
    "eval": [
      "service/*",
      "vendor-appnameservice.js"
    ]
  },
  "apis": {
    "vendor-appname": {
      "com.innovaphone.statistics": {}
    }
  }
}

Initialization

To initialize the library, pass an options object specifying table names:

var stats = new Statistics({
    datasetsTable: "statistics_datasets",
    dataTable: "statistics_data"
});

Methods

`createDataset(datasetName, type, callback)`

Creates a dataset if it doesn't already exist.

datasetName: string – The name of the dataset.
type (optional): "sum" or "max" – Aggregation type. Default is "sum".
callback (optional): function(obj, callback) – Called when dataset is created or retrieved. If a callback function is defined, the dataset exists only at runtime and is not saved in the database. In this case, the type parameter is ignored.

Examples:

stats.createDataset("pageViews", "sum");

stats.createDataset("cpuUsage", "max");

stats.createDataset("existingData", null, function(obj, callback){});

`insertData(datasetName, value)`

Inserts a numerical value into the current hour's bucket for the dataset.

datasetName: string – The dataset name.
value: number – The value to insert.

stats.insertData("pageViews", 1);

Notes

All timestamps are handled in UNIX epoch milliseconds.
Data is grouped per hour internally.

Example

This example initializes the Statistics Library and creates three datasets.
The dataset "customDataFromYourApp" uses a callback to a custom function getCustomData, which you can define within your app service.
Depending on your application, you can generate results for the specified interval and timeframe inside this callback.
The next property should be set to the timestamp of the next data request.
The counts property is an array containing the aggregated data. For mode === "live", it typically contains a single value based on the current result.

var stats = new Statistics({
    datasetsTable: "appname_stat_datasets",
    dataTable: "appname_stat_data"
})
.createDataset("usage")
.createDataset("cpu", "max")
.createDataset("customDataFromYourApp", null, getCustomData);

function getCustomData(obj, callback) {
    if (obj.mode === "live") {
        getCountsLive(obj.start, function (err, result) {
            if (err) {
                callback(err.error || "Unknown Error");
            } else if (result) {
                var data = { next: result.next, counts: result.counts };
                callback(null, data);
            } else {
                callback("No Results");
            }
        });
    } else {
        getCountsForPeriod(obj.start, obj.end, obj.mode, function (err, result) {
            if (err) {
                callback(err.error || "Unknown Error");
            } else if (result) {
                var data = { next: result.next, counts: result.counts };
                callback(null, data);
            } else {
                callback("No Results");
            }
        });
    }
}