Unable to use Azure Cache for Redis

[hallidev]

Summary of the issue

I just switched from EFCoreSecondLevelCache (the old package) to this new package, and I'm unable to get Redis caching to work using Azure Cache for Redis. I have a Standard Tier Redis cache configured in Azure like so:

The Redis cache config looks like this:

                cacheConfigurationBuilder
                    .WithJsonSerializer(cacheJsonSerializerSettings, cacheJsonSerializerSettings)
                    .WithRedisConfiguration(RedisCacheConfigKey, config =>
                    {
                        config.WithAllowAdmin()
                            .WithPassword(redisConfig.Password)
                            .WithDatabase(0)
                            .WithSsl(redisConfig.Endpoint)
                            .WithEndpoint(redisConfig.Endpoint, redisConfig.Port)
                        .EnableKeyspaceEvents();
                    })
                    .WithRedisCacheHandle(RedisCacheConfigKey)
                    .WithExpiration(ExpirationMode.Absolute, TimeSpan.FromMinutes(10));

With all of the above, any query run against the DbContext throws this exception:

'ERR unknown command CONFIG, with args beginning with: GET, notify-keyspace-events, '

Stack Trace:

at StackExchange.Redis.ConnectionMultiplexer.ExecuteSyncImpl[T](Message message, ResultProcessor1 processor, ServerEndPoint server) in C:\projects\stackexchange-redis\src\StackExchange.Redis\ConnectionMultiplexer.cs:line 2231 at StackExchange.Redis.RedisBase.ExecuteSync[T](Message message, ResultProcessor1 processor, ServerEndPoint server) in C:\projects\stackexchange-redis\src\StackExchange.Redis\RedisBase.cs:line 54
at StackExchange.Redis.RedisServer.ExecuteSync[T](Message message, ResultProcessor1 processor, ServerEndPoint server) in C:\projects\stackexchange-redis\src\StackExchange.Redis\RedisServer.cs:line 585 at StackExchange.Redis.RedisServer.ConfigGet(RedisValue pattern, CommandFlags flags) in C:\projects\stackexchange-redis\src\StackExchange.Redis\RedisServer.cs:line 152 at CacheManager.Redis.RedisConnectionManager.GetConfiguration(String key) at CacheManager.Redis.RedisCacheHandle1..ctor(ICacheManagerConfiguration managerConfiguration, CacheHandleConfiguration configuration, ILoggerFactory loggerFactory, ICacheSerializer serializer)

[VahidN]

This error is related to EnableKeyspaceEvents() setting.

It enables keyspace notifications to react on eviction/expiration of items.
Make sure that all servers are configured correctly and 'notify-keyspace-events' is at least set to 'Exe', otherwise CacheManager will not retrieve any events.
See https://redis.io/topics/notifications#configuration for configuration details.

If you can't set it, just remove that line.

[hallidev]

@VahidN Appreciate the quick response. Great library by the way, I've been relying on it for a while now.

When I remove EnableKeyspaceEvents(), all my queries throw the following exception:

NullReferenceException:

at EFCoreSecondLevelCacheInterceptor.EFTableRowsDataReader.GetInt16(Int32 ordinal)
at Microsoft.EntityFrameworkCore.Query.Internal.QueryingEnumerable1.AsyncEnumerator.<MoveNextAsync>d__17.MoveNext() at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) at Microsoft.EntityFrameworkCore.EntityFrameworkQueryableExtensions.<ToListAsync>d__641.MoveNext()
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
at Microsoft.EntityFrameworkCore.EntityFrameworkQueryableExtensions.d__641.MoveNext() at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at System.Runtime.CompilerServices.TaskAwaiter1.GetResult()

[VahidN]

• You can try Egx or eA value for the notify-keyspace-events too.
• What's your setting for GetInt16 field? What db is in use?

[hallidev]

On closer inspection, only .Cacheable() queries are throwing the NullReferenceException. I've tried switching between the keyspace event types - same result.

It's not just GetInt16 that's failing - it seems it fails on any GetXXX call with the NullReferenceException.

What do you mean by settings for GetInt16 though?

Also, I'm using an Azure SQL database.

[VahidN]

Probably you have a nullable property. It's fixed via #b172fed

[hallidev]

Ah yes - I have many nullable properties. I'm sure that's it.

Funny enough, I installed 1.4.0 this morning and noticed you released 1.5.0 shortly afterwards. Will you be pushing another nuget package?

Again, your work on this is very much appreciated.

[hallidev]

I just took a quick at your change - would it only affect Redis caching? The in-memory caching seems to be working fine, but I'm not sure if that uses a totally different mechanism.

[VahidN]

• NuGet's site waits for 5 minutes to make the uploaded package public. It's public now.
• Yes, the Redis one uses a different serializer behind the scene.

[hallidev]

Just took the package and it does get quite a bit further, but ultimately fails on objects that have a nullable DateTime:

System.InvalidCastException: 'Unable to cast object of type 'System.DateTime' to type 'System.DateTimeOffset'.'

   at System.Data.Common.DbDataReader.GetFieldValue[T](Int32 ordinal)
   at Microsoft.EntityFrameworkCore.Query.Internal.QueryingEnumerable`1.AsyncEnumerator.<MoveNextAsync>d__17.MoveNext()
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Runtime.CompilerServices.ValueTaskAwaiter`1.GetResult()
   at Microsoft.EntityFrameworkCore.Query.ShapedQueryCompilingExpressionVisitor.<SingleOrDefaultAsync>d__22`1.MoveNext()
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at Microsoft.EntityFrameworkCore.Query.ShapedQueryCompilingExpressionVisitor.<SingleOrDefaultAsync>d__22`1.MoveNext()
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter`1.GetResult()

None of my values are stored as DateTimeOffset - they're all defined like this:

public DateTime? LastLoginUtc { get; set; }

[VahidN]

Try setting:

var jss = new JsonSerializerSettings
            {
                NullValueHandling = NullValueHandling.Ignore,
                ReferenceLoopHandling = ReferenceLoopHandling.Ignore,
                TypeNameHandling = TypeNameHandling.Objects, // set this if you have binary data

                DateFormatHandling = DateFormatHandling.IsoDateFormat,
                DateParseHandling = DateParseHandling.DateTimeOffset,
                DateTimeZoneHandling = DateTimeZoneHandling.Utc,
            };

[VahidN]

This is a better solution and converts special data types correctly:

var jss = new JsonSerializerSettings
{
    NullValueHandling = NullValueHandling.Ignore,
    ReferenceLoopHandling = ReferenceLoopHandling.Ignore,
    TypeNameHandling = TypeNameHandling.Objects, // set this if you have binary data
    Converters = { new SpecialTypesConverter() }
};

And here is the definition of the SpecialTypesConverter.

[hallidev]

So strange - I'm still getting the same exception.

I should have mentioned this above, but I've been using the following JsonSerializerSettings with EFCoreSecondLevelCache for a long time:

            var cacheJsonSerializerSettings = new JsonSerializerSettings
            {
                TypeNameHandling = TypeNameHandling.Auto,
                NullValueHandling = NullValueHandling.Ignore,
                ReferenceLoopHandling = ReferenceLoopHandling.Ignore
            };

When I'm developing locally I use CacheManager's memory cache, and in other environments use Redis.

My memory cache config looks like this, and is currently working fine with the new package:

            cacheConfigurationBuilder
                .WithJsonSerializer(cacheJsonSerializerSettings, cacheJsonSerializerSettings)
                .WithMicrosoftMemoryCacheHandle()
                .WithExpiration(ExpirationMode.Absolute, TimeSpan.FromMinutes(10));

I'd be surprised if this was serialization related as these serialization settings have been working so reliably for so long, but I'll admit I have no clue what the internals of your package look like.

[VahidN]

The mentioned solution has been tested with this entity will all of the possible data types. This is the final settings for the Redis provider.

[hallidev]

Just in case this helps anyone in the future -

My issue with the DateTime conversion all boiled down to the property LockoutEnd stored on the base IdentityUser class, which I don't use directly. This property is a DateTimeOffset rather than DateTime.

The proper date type information was being lost as @VahidN points out, and his fix looks to be the correct fix. The issues I was experiencing after implementing the SpecialTypesConverter were related to other spots in code where I use the Redis cache unrelated to EFCoreSecondLevelCacheInterceptor.

My problem was here:

TypeNameHandling = TypeNameHandling.Objects,

My unrelated caching code started deserializing to the JObject type after introducing TypeNameHandling.Objects.

Switching back to TypeNameHandling.Auto along with the use of SpecialTypesConverter fixed my issue.

My serializer settings now look like this:

            var cacheJsonSerializerSettings = new JsonSerializerSettings
            {
                Converters = { new StrongDateTypesConverter() }, 
                TypeNameHandling = TypeNameHandling.Auto,
                NullValueHandling = NullValueHandling.Ignore,
                ReferenceLoopHandling = ReferenceLoopHandling.Ignore
            };

I guess the takeaway is to be sure to be careful with your serializer settings.