Merge pull request #33 from espenekvang/feature/distributed-cache-exception

Log exception from distributed cache

Author: brockallen

src/Duende.AccessTokenManagement/ClientCredentialsTokenManagementService.cs

@@ -1,6 +1,7 @@
 // Copyright (c) Brock Allen & Dominick Baier. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See LICENSE in the project root for license information.
 
+using System;
 using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.Extensions.Logging;
@@ -46,10 +47,19 @@ public async Task<ClientCredentialsToken> GetAccessTokenAsync(
 
         if (parameters.ForceRenewal == false)
         {
-            var item = await _tokenCache.GetAsync(clientName, parameters, cancellationToken).ConfigureAwait(false);
-            if (item != null)
+            try
             {
-                return item;
+                var item = await _tokenCache.GetAsync(clientName, parameters, cancellationToken).ConfigureAwait(false);
+                if (item != null)
+                {
+                    return item;
+                }
+            }
+            catch (Exception e)
+            {
+                _logger.LogError(e,
+                    "Error trying to obtain token from cache for client {clientName}. Error = {error}. Will obtain new token.", 
+                    clientName, e.Message);
             }
         }
 
@@ -65,7 +75,17 @@ public async Task<ClientCredentialsToken> GetAccessTokenAsync(
                 return token;
             }
 
-            await _tokenCache.SetAsync(clientName, token, parameters, cancellationToken).ConfigureAwait(false);
+            try
+            {
+                await _tokenCache.SetAsync(clientName, token, parameters, cancellationToken).ConfigureAwait(false);
+            }
+            catch (Exception e)
+            {
+                _logger.LogError(e,
+                    "Error trying to set token in cache for client {clientName}. Error = {error}", 
+                    clientName, e.Message);
+            }
+
             return token;
         }).ConfigureAwait(false);
     }

test/Tests/ClientTokenManagementTests.cs

@@ -2,6 +2,7 @@
 using System.Text.Json;
 using IdentityModel;
 using IdentityModel.Client;
+using Microsoft.Extensions.Caching.Distributed;
 using Microsoft.Extensions.DependencyInjection;
 using RichardSzalay.MockHttp;
 
@@ -433,6 +434,46 @@ public async Task Service_should_hit_network_only_once_and_then_use_cache()
         token.AccessTokenType.ShouldBe("token_type");
         mockHttp.GetMatchCount(mockedRequest).ShouldBe(1);
     }
+    
+    [Fact]
+    public async Task Service_should_hit_network_when_cache_throws_exception()
+    {
+        var services = new ServiceCollection();
+
+        services.AddTransient<IDistributedCache, TestDistributedCache>();
+        services.AddClientCredentialsTokenManagement()
+            .AddClient("test", client =>
+            {
+                client.TokenEndpoint = "https://as/connect/token";
+                client.ClientId = "client_id";
+            });
+
+        var response = new
+        {
+            access_token = "access_token",
+            token_type = "token_type",
+            expires_in = 3600,
+            scope = "scope"
+        };
+
+        var mockHttp = new MockHttpMessageHandler();
+        mockHttp.Fallback.Throw(new InvalidOperationException("No matching mock handler"));
+
+        var mockedRequest = mockHttp.Expect("/connect/token")
+            .Respond("application/json", JsonSerializer.Serialize(response));
+
+        services.AddHttpClient(ClientCredentialsTokenManagementDefaults.BackChannelHttpClientName)
+            .ConfigurePrimaryHttpMessageHandler(() => mockHttp);
+
+        var provider = services.BuildServiceProvider();
+        var sut = provider.GetRequiredService<IClientCredentialsTokenManagementService>();
+
+        var token = await sut.GetAccessTokenAsync("test");
+        token.IsError.ShouldBeFalse();
+        token.AccessToken.ShouldBe("access_token");
+        token.AccessTokenType.ShouldBe("token_type");
+        mockHttp.GetMatchCount(mockedRequest).ShouldBe(1);
+    }
 
     [Fact]
     public async Task Service_should_always_hit_network_with_force_renewal()

test/Tests/Framework/TestDistributedCache.cs

@@ -0,0 +1,51 @@
+using Microsoft.Extensions.Caching.Distributed;
+
+namespace Duende.AccessTokenManagement.Tests;
+
+internal class TestDistributedCache : IDistributedCache
+{
+    private readonly Dictionary<string, byte[]> _cache = new();
+    
+    public byte[] Get(string key)
+    {
+        return _cache[key];
+    }
+
+    public Task<byte[]> GetAsync(string key, CancellationToken token = new CancellationToken())
+    {
+        return Task.FromResult(_cache[key]);
+    }
+
+    public void Refresh(string key)
+    {
+    }
+
+    public Task RefreshAsync(string key, CancellationToken token = new CancellationToken())
+    {
+        Refresh(key);
+        return Task.CompletedTask;
+    }
+
+    public void Remove(string key)
+    {
+        _cache.Remove(key);
+    }
+
+    public Task RemoveAsync(string key, CancellationToken token = new CancellationToken())
+    {
+        Remove(key);
+        return Task.CompletedTask;
+    }
+
+    public void Set(string key, byte[] value, DistributedCacheEntryOptions options)
+    {
+        _cache.Add(key, value);
+    }
+
+    public Task SetAsync(string key, byte[] value, DistributedCacheEntryOptions options,
+        CancellationToken token = new CancellationToken())
+    {
+        Set(key, value, options);
+        return Task.CompletedTask;
+    }
+}