Reload license when file or options change

src/IdentityServer/Licensing/v2/LicenseAccessor.cs

@@ -10,6 +10,7 @@
 using System.Security.Cryptography;
 using Duende.IdentityServer.Configuration;
 using Microsoft.Extensions.Logging;
+using Microsoft.Extensions.Options;
 using Microsoft.IdentityModel.JsonWebTokens;
 using Microsoft.IdentityModel.Tokens;
 
@@ -18,16 +19,50 @@ namespace Duende.IdentityServer.Licensing.v2;
 /// <summary>
 /// Loads the license from configuration or a file, and validates its contents.
 /// </summary>
-internal class LicenseAccessor(IdentityServerOptions options, ILogger<LicenseAccessor> logger) : ILicenseAccessor
+internal class LicenseAccessor : ILicenseAccessor
 {
     static readonly string[] LicenseFileNames =
     [
         "Duende_License.key",
         "Duende_IdentityServer_License.key",
     ];
 
+    private IOptionsMonitor<IdentityServerOptions> _options;
+    private readonly ILogger<LicenseAccessor> _logger;
+    private readonly FileSystemWatcher _watcher;
+
+    public LicenseAccessor(IOptionsMonitor<IdentityServerOptions> options, ILogger<LicenseAccessor> logger)
+    {
+        _options = options;
+        _logger = logger;
+
+        // If the options change, discard the license so that we will read updates
+        _options.OnChange(opt =>
+        {
+            _license = null;
+        });
+
+        // If the license key file changes in any way, discard the license so that we will read updates
+        _watcher = new FileSystemWatcher(Directory.GetCurrentDirectory());
+        _watcher.Filter = "*.key";
+        _watcher.Changed += DiscardLicense;
+        _watcher.Deleted += DiscardLicense;
+        _watcher.Created += DiscardLicense;
+        _watcher.Renamed += DiscardLicense;
+
+        _watcher.EnableRaisingEvents = true;
+    }
+
+
+    private void DiscardLicense(object sender, FileSystemEventArgs e)
+    {
+        _logger.LogDebug("License file change detected, license will be reloaded");
+        _license = null;
+    }
+
     private License? _license;
     private readonly object _lock = new();
+
     public License Current => _license ??= Initialize();
 
     private License Initialize()
@@ -36,7 +71,7 @@ private License Initialize()
         {
             if (_license != null) return _license;
 
-            var key = options.LicenseKey;
+            var key = _options.CurrentValue.LicenseKey;
             if (key == null)
             {
                 key = LoadLicenseKeyFromFile();
@@ -96,7 +131,7 @@ private Claim[] ValidateKey(string licenseKey)
         var validateResult = handler.ValidateTokenAsync(licenseKey, parms).Result;
         if (!validateResult.IsValid)
         {
-            logger.LogCritical(validateResult.Exception, "Error validating the Duende software license key");
+            _logger.LogCritical(validateResult.Exception, "Error validating the Duende software license key");
         }
 
         return validateResult.ClaimsIdentity?.Claims.ToArray() ?? [];

test/IdentityServer.UnitTests/Licensing/v2/LicenseAccessorTests.cs

@@ -7,28 +7,61 @@
 using Duende.IdentityServer.Configuration;
 using FluentAssertions;
 using Microsoft.Extensions.Logging.Testing;
+using Microsoft.Extensions.Options;
 using Xunit;
 
 namespace IdentityServer.UnitTests.Licensing.v2;
 
+public class TestOptionsMonitor<TOptions> : IOptionsMonitor<TOptions>
+{
+    private Action<TOptions, string> _listener;
+
+    public TestOptionsMonitor(TOptions currentValue)
+    {
+        CurrentValue = currentValue;
+    }
+
+    public TOptions CurrentValue { get; private set; }
+
+    public TOptions Get(string name)
+    {
+        return CurrentValue;
+    }
+
+    public void Set(TOptions value)
+    {
+        CurrentValue = value;
+        _listener.Invoke(value, null);
+    }
+
+    public IDisposable OnChange(Action<TOptions, string> listener)
+    {
+        _listener = listener;
+        return null;
+    }
+}
+
 public class LicenseAccessorTests
 {
+    private readonly TestOptionsMonitor<IdentityServerOptions> _optionsMonitor;
     private readonly IdentityServerOptions _options;
     private readonly LicenseAccessor _licenseAccessor;
     private readonly FakeLogger<LicenseAccessor> _logger;
 
     public LicenseAccessorTests()
     {
         _options = new IdentityServerOptions();
+        _optionsMonitor = new TestOptionsMonitor<IdentityServerOptions>(_options);
         _logger = new FakeLogger<LicenseAccessor>();
-        _licenseAccessor = new LicenseAccessor(_options, _logger);
+        _licenseAccessor = new LicenseAccessor(_optionsMonitor, _logger);
     }
 
     [Theory]
     [MemberData(nameof(LicenseTestCases))]
     internal void license_set_in_options_is_parsed_correctly(int serialNumber, LicenseEdition edition, bool isRedistribution, string contact, bool addDynamicProviders, bool addKeyManagement, string key)
     {
         _options.LicenseKey = key;
+        _optionsMonitor.Set(_options);
 
         var l = _licenseAccessor.Current;
 
@@ -55,7 +88,6 @@ internal void license_set_in_options_is_parsed_correctly(int serialNumber, Licen
         _licenseAccessor.Current.IsEnabled(LicenseFeature.ServerSideSessions).Should().Be(businessFeaturesEnabled);
     }
 
-
     public static IEnumerable<object[]> LicenseTestCases() =>
     [
         // Order of parameters is: int serialNumber, LicenseEdition edition, bool isRedistribution, string contact, string key
@@ -76,13 +108,12 @@ public static IEnumerable<object[]> LicenseTestCases() =>
         [6681, LicenseEdition.Business, false, "[email protected]", true, false, "eyJhbGciOiJQUzI1NiIsImtpZCI6IklkZW50aXR5U2VydmVyTGljZW5zZWtleS83Y2VhZGJiNzgxMzA0NjllODgwNjg5MTAyNTQxNGYxNiIsInR5cCI6ImxpY2Vuc2Urand0In0.eyJpc3MiOiJodHRwczovL2R1ZW5kZXNvZnR3YXJlLmNvbSIsImF1ZCI6IklkZW50aXR5U2VydmVyIiwiaWF0IjoxNzMwNDE5MjAwLCJleHAiOjE3MzE2Mjg4MDAsImNvbXBhbnlfbmFtZSI6Il90ZXN0IiwiY29udGFjdF9pbmZvIjoiam9lQGR1ZW5kZXNvZnR3YXJlLmNvbSIsImVkaXRpb24iOiJCdXNpbmVzcyIsImlkIjoiNjY4MSIsImZlYXR1cmUiOiJkeW5hbWljX3Byb3ZpZGVycyJ9.HeCNt4O1cXsw4Ujkn2W_sDRmWUDstYtLPQ7UhYvneUgxed7auFyroBJojkwh9RwflWD1HphHYx4KRuZML_OO0BYzGr865gWI55x6KxHM5mxY5hpVJMTLottSgIv-hyXdNxTWCxP1jluzs1b4JgWmXnU83AuRtAenMpZpZcOY7Pldkd84JA1BXE5gEM6v2U8HCTgydY1QmTd_RjYlicGqmDOkKALiHOxREyXLsRgy4pmQfG6gs99heXdzs2k4jRLLXsTFHP7UxupRTYDPCgXT19ub6l4KG95rPBSMV_vXEwydcFGJe1uFQdd1btUSVe50XX1hmZx4P4SymlX0iuimMg"],
         [6680, LicenseEdition.Starter, false, "[email protected]", false, true, "eyJhbGciOiJQUzI1NiIsImtpZCI6IklkZW50aXR5U2VydmVyTGljZW5zZWtleS83Y2VhZGJiNzgxMzA0NjllODgwNjg5MTAyNTQxNGYxNiIsInR5cCI6ImxpY2Vuc2Urand0In0.eyJpc3MiOiJodHRwczovL2R1ZW5kZXNvZnR3YXJlLmNvbSIsImF1ZCI6IklkZW50aXR5U2VydmVyIiwiaWF0IjoxNzMwNDE5MjAwLCJleHAiOjE3MzE2Mjg4MDAsImNvbXBhbnlfbmFtZSI6Il90ZXN0IiwiY29udGFjdF9pbmZvIjoiam9lQGR1ZW5kZXNvZnR3YXJlLmNvbSIsImVkaXRpb24iOiJTdGFydGVyIiwiaWQiOiI2NjgwIiwiZmVhdHVyZSI6ImtleV9tYW5hZ2VtZW50In0.kmArT0vjFE4nhRNg_kchOh_uklaqm3KeworQ9up_4jIBOinbZtVv3NkXtJoHX_lzjs1ftp0eNMSyGg6E29GR7ZZ2hx3SQdQrSdrH4v_sNSFcRZrwzipXBkANssH-0hMQ0s3kdfXdwfmN_8IfCkPCugeMemwUWwbC7QHBdCa6Fr7ZExuMNLpml932D72LMzhlLf780BSic9PKn6odvzGikYK9e2WhYL1zL0REdNHzgwrrUZHesZF98u-gel7skS1Frg6cBcPl_QSSP5KhxmfdPw0b2FUM_B0Tpi-gN54efz0stzccjr9PgcpAfXO82y3vOBB7f44cdv6DG67YwAvv0A"]
     ];
-
-
 
     [Fact]
     public void keys_that_cannot_be_parsed_are_treated_the_same_as_an_absent_license()
     {
         _options.LicenseKey = "invalid key";
+        _optionsMonitor.Set(_options);
         _licenseAccessor.Current.IsConfigured.Should().BeFalse();
         _logger.Collector.GetSnapshot().Should().Contain(r => 
             r.Message == "Error validating the Duende software license key");