Log background cache refresh failures in LocationResolver

src/IceRpc.Locator/Internal/LocationResolver.cs

@@ -29,6 +29,17 @@ internal static partial void LogFailedToResolve(
         string locationKind,
         Location location,
         Exception? exception = null);
+
+    [LoggerMessage(
+        EventId = (int)LocationEventId.BackgroundRefreshFailed,
+        EventName = nameof(LocationEventId.BackgroundRefreshFailed),
+        Level = LogLevel.Debug,
+        Message = "Background cache refresh failed for {LocationKind} '{Location}'")]
+    internal static partial void LogBackgroundRefreshFailed(
+        this ILogger logger,
+        string locationKind,
+        Location location,
+        Exception exception);
 }
 
 /// <summary>An implementation of <see cref="ILocationResolver" /> without a cache.</summary>
@@ -67,6 +78,7 @@ internal CacheLessLocationResolver(IServerAddressFinder serverAddressFinder) =>
 internal class LocationResolver : ILocationResolver
 {
     private readonly bool _background;
+    private readonly ILogger _logger;
     private readonly IServerAddressCache _serverAddressCache;
     private readonly IServerAddressFinder _serverAddressFinder;
     private readonly TimeSpan _refreshThreshold;
@@ -78,13 +90,15 @@ internal LocationResolver(
         IServerAddressCache serverAddressCache,
         bool background,
         TimeSpan refreshThreshold,
-        TimeSpan ttl)
+        TimeSpan ttl,
+        ILogger logger)
     {
         _serverAddressFinder = serverAddressFinder;
         _serverAddressCache = serverAddressCache;
         _background = background;
         _refreshThreshold = refreshThreshold;
         _ttl = ttl;
+        _logger = logger;
     }
 
     public ValueTask<(ServiceAddress? ServiceAddress, bool FromCache)> ResolveAsync(
@@ -118,7 +132,7 @@ internal LocationResolver(
         else if (_background && expired)
         {
             // We retrieved an expired service address from the cache, so we launch a refresh in the background.
-            _ = _serverAddressFinder.FindAsync(location, cancellationToken: default).ConfigureAwait(false);
+            _ = RefreshInBackgroundAsync();
         }
 
         // A well-known service address resolution can return a service address with an adapter-id.
@@ -150,6 +164,18 @@ internal LocationResolver(
         }
 
         return (serviceAddress, serviceAddress is not null && !resolved);
+
+        async Task RefreshInBackgroundAsync()
+        {
+            try
+            {
+                _ = await _serverAddressFinder.FindAsync(location, cancellationToken: default).ConfigureAwait(false);
+            }
+            catch (Exception exception)
+            {
+                _logger.LogBackgroundRefreshFailed(location.Kind, location, exception);
+            }
+        }
     }
 }
 

src/IceRpc.Locator/LocationEventId.cs

@@ -25,5 +25,8 @@ public enum LocationEventId
     FindFailed,
 
     /// <summary>The server address finder found server address(es) for the given location.</summary>
-    Found
+    Found,
+
+    /// <summary>A background cache refresh failed.</summary>
+    BackgroundRefreshFailed
 }

src/IceRpc.Locator/LocatorInterceptor.cs

@@ -221,7 +221,8 @@ public LocatorLocationResolver(ILocator locator, LocatorOptions options, ILogger
                 serverAddressCache,
                 options.Background,
                 options.RefreshThreshold,
-                options.Ttl);
+                options.Ttl,
+                logger);
         if (logger != NullLogger.Instance)
         {
             _locationResolver = new LogLocationResolverDecorator(_locationResolver, logger);

tests/IceRpc.Locator.Tests/LocationResolverTests.cs

@@ -1,6 +1,7 @@
 // Copyright (c) ZeroC, Inc.
 
 using IceRpc.Locator.Internal;
+using Microsoft.Extensions.Logging.Abstractions;
 using NUnit.Framework;
 
 namespace IceRpc.Locator.Tests;
@@ -21,7 +22,8 @@ public async Task ServerAddress_finder_not_called_when_cache_entry_age_is_less_o
                 new MockServerAddressCache(cachedServiceAddress, insertionTime: TimeSpan.FromSeconds(cacheEntryAge)),
                 background: false,
                 TimeSpan.FromSeconds(refreshThreshold),
-                ttl: Timeout.InfiniteTimeSpan);
+                ttl: Timeout.InfiniteTimeSpan,
+                NullLogger.Instance);
 
         (ServiceAddress? resolved, bool _) = await resolver.ResolveAsync(default, refreshCache: true, default);
 
@@ -44,7 +46,8 @@ public async Task ServerAddress_finder_called_when_cache_entry_age_is_greater_th
                 new MockServerAddressCache(cachedServiceAddress, insertionTime: TimeSpan.FromSeconds(cacheEntryAge)),
                 background: false,
                 TimeSpan.FromSeconds(refreshThreshold),
-                ttl: Timeout.InfiniteTimeSpan);
+                ttl: Timeout.InfiniteTimeSpan,
+                NullLogger.Instance);
 
         (ServiceAddress? resolved, bool _) = await resolver.ResolveAsync(default, refreshCache: true, default);
 
@@ -64,7 +67,8 @@ public async Task ServerAddress_finder_called_on_background()
                 new MockServerAddressCache(cachedServiceAddress, insertionTime: TimeSpan.FromSeconds(120)),
                 background: true,
                 TimeSpan.FromSeconds(1),
-                ttl: TimeSpan.FromSeconds(30));
+                ttl: TimeSpan.FromSeconds(30),
+                NullLogger.Instance);
 
         (ServiceAddress? resolved, bool fromCache) = await resolver.ResolveAsync(default, refreshCache: false, default);
 
@@ -84,7 +88,8 @@ public async Task Location_recursive_resolution()
                 new MockServerAddressCache(),
                 background: true,
                 TimeSpan.FromSeconds(1),
-                ttl: TimeSpan.FromSeconds(30));
+                ttl: TimeSpan.FromSeconds(30),
+                NullLogger.Instance);
 
         (ServiceAddress? resolved, bool fromCache) = await resolver.ResolveAsync(
             new Location
@@ -111,7 +116,8 @@ public async Task Failure_to_recursively_resolve_adapter_id_removes_proxy_from_c
                 serverAddressCache,
                 background: true,
                 TimeSpan.FromSeconds(1),
-                ttl: TimeSpan.FromSeconds(30));
+                ttl: TimeSpan.FromSeconds(30),
+                NullLogger.Instance);
         var location = new Location
         {
             Value = "/hello",