Adding version check to startup

src/Core/VersionChecker.cs

@@ -0,0 +1,49 @@
+using System.Net.Http.Json;
+using System.Reflection;
+using System.Text.Json.Serialization;
+
+namespace Azure.DataApiBuilder.Core;
+
+public static class VersionChecker
+{
+    public static void GetVersions(out string? latestVersion, out string? currentVersion)
+    {
+        latestVersion = FetchLatestNuGetVersion();
+        currentVersion = GetCurrentVersionFromAssembly(Assembly.GetCallingAssembly());
+    }
+
+    private static string? FetchLatestNuGetVersion()
+    {
+        try
+        {
+            using HttpClient httpClient = new() { Timeout = TimeSpan.FromSeconds(2) };
+            NuGetVersionResponse? versionData = httpClient
+                .GetFromJsonAsync<NuGetVersionResponse>("https://api.nuget.org/v3-flatcontainer/microsoft.dataapibuilder/index.json")
+                .GetAwaiter().GetResult();
+
+            return versionData?.Versions
+                ?.Where(version => !version.Contains("-rc")) // Filter out pre-release versions
+                .Select(version => new Version(version))     // Convert to Version objects
+                .Max()?.ToString();                          // Get the latest 
+        }
+        catch (Exception)
+        {
+            return null; // Assume no update available on failure
+        }
+    }
+
+    private static string? GetCurrentVersionFromAssembly(Assembly assembly)
+    {
+        string? version = assembly.GetCustomAttribute<AssemblyInformationalVersionAttribute>()?.InformationalVersion;
+
+        return version is { Length: > 0 } && version.Contains('+')
+            ? version[..version.IndexOf('+')] // Slice version string before '+'
+            : version ?? assembly.GetName().Version?.ToString();
+    }
+
+    private class NuGetVersionResponse
+    {
+        [JsonPropertyName("versions")]
+        public string[]? Versions { get; set; }
+    }
+}

src/Service.Tests/Unittests/VersionCheckTests.cs

@@ -0,0 +1,26 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+using Azure.DataApiBuilder.Core;
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+
+namespace Cli.Tests
+{
+    [TestClass]
+    public class VersionCheckTests
+    {
+        [TestMethod]
+        public void GetVersions_LatestVersionNotNull()
+        {
+            VersionChecker.GetVersions(out string latestVersion, out string _);
+            Assert.IsNotNull(latestVersion, "Latest version should not be null.");
+        }
+
+        [TestMethod]
+        public void GetVersions_CurrentVersionNotNull()
+        {
+            VersionChecker.GetVersions(out string _, out string currentVersion);
+            Assert.IsNotNull(currentVersion, "Current version should not be null.");
+        }
+    }
+}

src/Service/Program.cs

@@ -7,6 +7,7 @@
 using System.Linq;
 using System.Threading.Tasks;
 using Azure.DataApiBuilder.Config;
+using Azure.DataApiBuilder.Core;
 using Azure.DataApiBuilder.Service.Exceptions;
 using Microsoft.ApplicationInsights;
 using Microsoft.AspNetCore;
@@ -27,6 +28,13 @@ public class Program
 
         public static void Main(string[] args)
         {
+            // Compare current version of DAB with latest (non-rc) version in NuGet. 
+            VersionChecker.GetVersions(out string? latestVersion, out string? currentVersion);
+            if (!string.IsNullOrEmpty(latestVersion) && latestVersion != currentVersion)
+            {
+                Console.Error.WriteLine($"A newer version of Data API builder is available. {currentVersion} -> {latestVersion}");
+            }
+
             if (!ValidateAspNetCoreUrls())
             {
                 Console.Error.WriteLine("Invalid ASPNETCORE_URLS format. e.g.: ASPNETCORE_URLS=\"http://localhost:5000;https://localhost:5001\"");