Power BI streaming data sets: The good, the great, and the gotchas

Listing 1 – The KPI Simulator Azure Function code (C# Script)

/*
--------------------------------
KPI Simulator
by Ross W. Lambert
Blueprint Technologies
Copyright (c) 2018
All Rights Reserved       
--------------------------------
*/
#r "Newtonsoft.Json"
using System;
using System.Collections;
using System.Net;
using System.Net.Http;
using Newtonsoft.Json;
// some constants for our simulated data
private static readonly double MAX_VARIANCE_PCT = 0.75;
private static readonly String NAME = "KPI-Simulator";
private static readonly String APICONFIG = "powerBiApiUrl";
private static readonly int MIN_PLAYERS = 10000;
private static readonly int MAX_PLAYERS = MIN_PLAYERS + (int) (MIN_PLAYERS * MAX_VARIANCE_PCT);
private static readonly int MIN_PURHCASES = 100;
private static readonly int MAX_PURHCASES = MIN_PURHCASES + (int) (MIN_PURHCASES * MAX_VARIANCE_PCT);
private static readonly int MIN_HELPREQ = 50;
private static readonly int MAX_HELPREQ = MIN_HELPREQ + (int) (MIN_HELPREQ * MAX_VARIANCE_PCT);
private static readonly int MIN_LOGINS = 200;
private static readonly int MAX_LOGINS = MIN_LOGINS + (int) (MIN_LOGINS * MAX_VARIANCE_PCT);
// share a client so as to not exhaust resources
private static readonly HttpClient client = new HttpClient();
// one random number generator to rule them all
private static readonly Random randomGenerator = new Random();
// little private class to hold our KPIs
private class KPI 
{
    // properties
    public DateTime Datetime { get; set; }
    public int OnlinePlayers { get; set; }
    public int HelpReqLast60Min { get; set; }
    public int InAppPurchasesLast60Min { get; set; }
    public int LoginsLast60Min { get; set; }
    
    // full constructor     
    public KPI(int onlinePlayerCnt, int helpReqCnt, int inAppPurchasesCnt, int loginsCount)
    {
        this.Datetime = DateTime.Now;
        this.OnlinePlayers = onlinePlayerCnt;
        this.HelpReqLast60min = helpReqCnt;
        this.InAppPurchasesLast60min = inAppPurchasesCnt;
        this.LoginsLast60min = loginsCount;
    }
    
    // handy override to see contents
    public override String ToString() 
    {
        return $"{this.Datetime},Players Online: {this.OnlinePlayers}, HelpDesk Requests Last 60 Minutes: {this.HelpReqLast60min}, In-app Purchases Last 60 Minutes: {this.InAppPurchasesLast60min}, New Logins Last 60 Minutes: {this.LoginsLast60min}";
    }
}
///
/// helper method to POST simulated data to Power BI API
/// 
///URL of Power BI REST API
///Array of KPI instances
///TraceWriter instance
static async Task PostSimData(String url, KPI[] kpiArray, TraceWriter log)
{
    HttpResponseMessage response = await client.PostAsJsonAsync (url, kpiArray);
    response.EnsureSuccessStatusCode();
    log.Info($"{NAME} response: {response.ReasonPhrase}");
    return response;
}            
///
/// Main entry point for Azure FN
/// 
///Our timer (unused)
///A logger instance
public static void Run(TimerInfo myTimer, TraceWriter log)
{
    log.Info($"{NAME} Timer trigger function executed at: {DateTime.Now}");
    // extract Power BI REST API endpoint URL from config
    String powerBiApiUrl = System.Environment.GetEnvironmentVariable(APICONFIG, EnvironmentVariableTarget.Process);
    if (String.IsNullOrEmpty(powerBiApiUrl)) {
        throw new WebException($"{APICONFIG} not defined");
    }
   
    // set up simulated KPI data...
    // these could be database calls, file reads, calculations, 
    // or API calls to extract real-time information
    
    var onlinePlayerCnt = randomGenerator.Next(MIN_PLAYERS, MAX_PLAYERS);
    var helpReqCnt = randomGenerator.Next(MIN_HELPREQ, MAX_HELPREQ);
    var inAppPurchasesCnt = randomGenerator.Next(MIN_PURHCASES, MAX_PURHCASES);
    var loginsCount = randomGenerator.Next(MIN_LOGINS, MAX_LOGINS);
    
    // populate new KPI object instance
    var kpi = new KPI (onlinePlayerCnt, helpReqCnt, inAppPurchasesCnt, loginsCount);
    KPI[] kpiArray = new[] {kpi};
    var task = PostSimData(powerBiApiUrl, kpiArray, log);
    log.Info(kpi.ToString());
    var json = JsonConvert.SerializeObject(kpiArray);
    log.Info($"JSON request body: {json}");
    log.Info($"{NAME} completed.");
}