base on FusionCache is an easy to use, fast and robust hybrid cache with advanced resiliency features. <div align="center">  # FusionCache </div> <div align="center"> [](https://opensource.org/licenses/MIT)  </div> | 🙋‍♂️ Updating to `v1.0.0` ? please [read here](docs/Update_v1_0_0.md). | |:-------| ### FusionCache is an easy to use, fast and robust hybrid cache with advanced resiliency features. It was born after years of dealing with all sorts of different types of caches: memory, distributed, hybrid, HTTP caching, CDNs, browser cache, offline cache, you name it. So I've tried to put together these experiences and came up with FusionCache. <div style="text-align:center;">  </div> Being a hybrid cache means it can transparently work as either a normal memory cache (L1) or as a multi-level cache (L1+L2), where the distributed 2nd level (L2) can be any implementation of the standard `IDistributedCache` interface: this will get us better cold starts, better horizontal scalability, more resiliency and overall better performance. FusionCache also includes an optional [backplane](docs/Backplane.md) for realtime sync between multiple nodes and advanced resiliency features like [cache stampede](docs/CacheStampede.md) protection, a [fail-safe](docs/FailSafe.md) mechanism, [soft/hard timeouts](docs/Timeouts.md), [eager refresh](docs/EagerRefresh.md), full observability via [logging](docs/Logging.md) and [OpenTelemetry](docs/OpenTelemetry.md) and much more. ## 🏆 Award <div align="center">  </div> On August 2021, FusionCache received the [Google Open Source Peer Bonus Award](https://twitter.com/jodydonetti/status/1422550932433350666): here is the [official blogpost](https://opensource.googleblog.com/2021/09/announcing-latest-open-source-peer-bonus-winners.html). ## 📕 Getting Started With [🦄 A Gentle Introduction](docs/AGentleIntroduction.md) you'll get yourself comfortable with the overall concepts. Want to start using it immediately? There's a [⭐ Quick Start](#-quick-start) for you. Curious about what you can achieve from start to finish? There's a [👩‍🏫 Step By Step ](docs/StepByStep.md) guide. ## 📺 Media More into videos? I've been lucky enough to be invited on some shows and podcasts here and there: you can find them in the [Media](docs/Media.md) section. A good example is when the fine folks at [On .NET](https://learn.microsoft.com/en-us/shows/on-net/) invited me on the show to allow me to mumbling random caching stuff. <div align="center"> [](https://www.youtube.com/watch?v=hCswI2goi7s) </div> ## ✔ Features These are the **key features** of FusionCache: - [**🛡️ Cache Stampede**](docs/CacheStampede.md): automatic protection from the Cache Stampede problem - [**🔀 2nd level**](docs/CacheLevels.md): an optional 2nd level handled transparently, with any implementation of `IDistributedCache` - [**💣 Fail-Safe**](docs/FailSafe.md): a mechanism to avoids transient failures, by reusing an expired entry as a temporary fallback - [**⏱ Soft/Hard Timeouts**](docs/Timeouts.md): a slow factory (or distributed cache) will not slow down your application, and no data will be wasted - [**📢 Backplane**](docs/Backplane.md): in a multi-node scenario, it can notify the other nodes about changes in the cache, so all will be in-sync - [**↩️ Auto-Recovery**](docs/AutoRecovery.md): automatic handling of transient issues with retries and sync logic - [**🧙‍♂️ Adaptive Caching**](docs/AdaptiveCaching.md): for when you don't know upfront the cache duration, as it depends on the value being cached itself - [**🔂 Conditional Refresh**](docs/ConditionalRefresh.md): like HTTP Conditional Requests, but for caching - [**🦅 Eager Refresh**](docs/EagerRefresh.md): start a non-blocking background refresh before the expiration occurs - [**🔃 Dependency Injection + Builder**](docs/DependencyInjection.md): native support for Dependency Injection, with a nice fluent interface including a Builder support - [**📛 Named Caches**](docs/NamedCaches.md): easily work with multiple named caches, even if differently configured - [**♊ Auto-Clone**](docs/AutoClone.md): be sure that cached values returned can be safely modified - [**🔭 OpenTelemetry**](docs/OpenTelemetry.md): native observability support via OpenTelemetry - [**🚀 Background Distributed Operations**](docs/BackgroundDistributedOperations.md): distributed operations can easily be executed in the background, safely, for better performance - [**📜 Logging**](docs/Logging.md): comprehensive, structured and customizable, via the standard `ILogger` interface - [**💫 Fully sync/async**](docs/CoreMethods.md): native support for both the synchronous and asynchronous programming model - [**📞 Events**](docs/Events.md): a comprehensive set of events, both at a high level and at lower levels (memory/distributed) - [**🧩 Plugins**](docs/Plugins.md): extend FusionCache with additional behavior like adding support for metrics, statistics, etc... <details> <summary>Something more 😏 ?</summary> <br/> Also, FusionCache has some nice **additional features**: - **✅ Portable**: targets .NET Standard 2.0, so it can run almost everywhere - **✅ High Performance**: FusionCache is optimized to minimize CPU usage and memory allocations to get better performance and lower the cost of your infrastructure all while obtaining a more stable, error resilient application - **✅ Null caching**: explicitly supports caching of `null` values differently than "no value". This creates a less ambiguous usage, and typically leads to better performance because it avoids the classic problem of not being able to differentiate between *"the value was not in the cache, go check the database"* and *"the value was in the cache, and it was `null`"* - **✅ Circuit-breaker**: it is possible to enable a simple circuit-breaker for when the distributed cache or the backplane become temporarily unavailable. This will prevent those components to be hit with an excessive load of requests (that would probably fail anyway) in a problematic moment, so it can gracefully get back on its feet. More advanced scenarios can be covered using a dedicated solution, like <a href="https://github.com/App-vNext/Polly">Polly</a> - **✅ Dynamic Jittering**: setting `JitterMaxDuration` will add a small randomized extra duration to a cache entry's normal duration. This is useful to prevent variations of the <a href="https://en.wikipedia.org/wiki/Cache_stampede">Cache Stampede problem</a> in a multi-node scenario - **✅ Cancellation**: every method supports cancellation via the standard `CancellationToken`, so it is easy to cancel an entire pipeline of operation gracefully - **✅ Code comments**: every property and method is fully documented in code, with useful informations provided via IntelliSense or similar technologies - **✅ Fully annotated for [nullability](https://docs.microsoft.com/en-us/dotnet/csharp/nullable-references)**: every usage of nullable references has been annotated for a better flow analysis by the compiler </details> ## 📦 Packages Main packages: | Package Name | Version | Downloads | |--------------------------------|:---------------:|:---------:| | [ZiggyCreatures.FusionCache](https://www.nuget.org/packages/ZiggyCreatures.FusionCache/) <br/> The core package | [](https://www.nuget.org/packages/ZiggyCreatures.FusionCache/) |  | | [ZiggyCreatures.FusionCache.OpenTelemetry](https://www.nuget.org/packages/ZiggyCreatures.FusionCache.OpenTelemetry/) <br/> Adds native support for OpenTelemetry setup | [](https://www.nuget.org/packages/ZiggyCreatures.FusionCache.OpenTelemetry/) |  | | [ZiggyCreatures.FusionCache.Chaos](https://www.nuget.org/packages/ZiggyCreatures.FusionCache.Chaos/) <br/> A package to add some controlled chaos, for testing | [](https://www.nuget.org/packages/ZiggyCreatures.FusionCache.Chaos/) |  | Serializers: | Package Name | Version | Downloads | |--------------------------------|:---------------:|:---------:| | [ZiggyCreatures.FusionCache.Serialization.NewtonsoftJson](https://www.nuget.org/packages/ZiggyCreatures.FusionCache.Serialization.NewtonsoftJson/) <br/> A serializer, based on Newtonsoft Json.NET | [](https://www.nuget.org/packages/ZiggyCreatures.FusionCache.Serialization.NewtonsoftJson/) |  | | [ZiggyCreatures.FusionCache.Serialization.SystemTextJson](https://www.nuget.org/packages/ZiggyCreatures.FusionCache.Serialization.SystemTextJson/) <br/> A serializer, based on the new System.Text.Json | [](https://www.nuget.org/packages/ZiggyCreatures.FusionCache.Serialization.SystemTextJson/) |  | | [ZiggyCreatures.FusionCache.Serialization.NeueccMessagePack](https://www.nuget.org/packages/ZiggyCreatures.FusionCache.Serialization.NeueccMessagePack/) <br/> A MessagePack serializer, based on the most used [MessagePack](https://github.com/neuecc/MessagePack-CSharp) serializer on .NET | [](https://www.nuget.org/packages/ZiggyCreatures.FusionCache.Serialization.NeueccMessagePack/) |  | | [ZiggyCreatures.FusionCache.Serialization.ProtoBufNet](https://www.nuget.org/packages/ZiggyCreatures.FusionCache.Serialization.ProtoBufNet/) <br/> A Protobuf serializer, based on one of the most used [protobuf-net](https://github.com/protobuf-net/protobuf-net) serializer on .NET | [](https://www.nuget.org/packages/ZiggyCreatures.FusionCache.Serialization.ProtoBufNet/) |  | | [ZiggyCreatures.FusionCache.Serialization.CysharpMemoryPack](https://www.nuget.org/packages/ZiggyCreatures.FusionCache.Serialization.CysharpMemoryPack/) <br/> A serializer based on the uber fast new serializer by Neuecc, [MemoryPack](https://github.com/Cysharp/MemoryPack) | [](https://www.nuget.org/packages/ZiggyCreatures.FusionCache.Serialization.CysharpMemoryPack/) |  | | [ZiggyCreatures.FusionCache.Serialization.ServiceStackJson](https://www.nuget.org/packages/ZiggyCreatures.FusionCache.Serialization.ServiceStackJson/) <br/> A serializer based on the [ServiceStack](https://servicestack.net/) JSON serializer | [](https://www.nuget.org/packages/ZiggyCreatures.FusionCache.Serialization.ServiceStackJson/) |  | Backplanes: | Package Name | Version | Downloads | |--------------------------------|:---------------:|:---------:| | [ZiggyCreatures.FusionCache.Backplane.Memory](https://www.nuget.org/packages/ZiggyCreatures.FusionCache.Backplane.Memory/) <br/> An in-memory backplane (mainly for testing) | [](https://www.nuget.org/packages/ZiggyCreatures.FusionCache.Backplane.Memory/) |  | | [ZiggyCreatures.FusionCache.Backplane.StackExchangeRedis](https://www.nuget.org/packages/ZiggyCreatures.FusionCache.Backplane.StackExchangeRedis/) <br/> A Redis backplane, based on StackExchange.Redis | [](https://www.nuget.org/packages/ZiggyCreatures.FusionCache.Backplane.StackExchangeRedis/) |  | Third-party packages: | Package Name | Version | Downloads | |--------------------------------|:---------------:|:---------:| | [JoeShook.ZiggyCreatures.FusionCache.Metrics.Core](https://www.nuget.org/packages/JoeShook.ZiggyCreatures.FusionCache.Metrics.Core/) | [](https://www.nuget.org/packages/JoeShook.ZiggyCreatures.FusionCache.Metrics.Core/) |  | | [JoeShook.ZiggyCreatures.FusionCache.Metrics.EventCounters](https://www.nuget.org/packages/JoeShook.ZiggyCreatures.FusionCache.Metrics.EventCounters/) | [](https://www.nuget.org/packages/JoeShook.ZiggyCreatures.FusionCache.Metrics.EventCounters/) |  | | [JoeShook.ZiggyCreatures.FusionCache.Metrics.AppMetrics](https://www.nuget.org/packages/JoeShook.ZiggyCreatures.FusionCache.Metrics.AppMetrics/) | [](https://www.nuget.org/packages/JoeShook.ZiggyCreatures.FusionCache.Metrics.AppMetrics/) |  | ## ⭐ Quick Start FusionCache can be installed via the nuget UI (search for the `ZiggyCreatures.FusionCache` package) or via the nuget package manager console: ```PowerShell PM> Install-Package ZiggyCreatures.FusionCache ``` As an example, imagine having a method that retrieves a product from your database: ```csharp Product GetProductFromDb(int id) { // YOUR DATABASE CALL HERE } ``` 💡 This is using the **sync** programming model, but it would be equally valid with the newer **async** one for even better performance. To start using FusionCache the first thing is create a cache instance: ```csharp var cache = new FusionCache(new FusionCacheOptions()); ``` If instead you are using [DI (Dependency Injection)](docs/DependencyInjection.md) use this: ```csharp services.AddFusionCache(); ``` We can also specify some global options, like a default `FusionCacheEntryOptions` object to serve as a default for each call we'll make, with a duration of `2 minutes`: ```csharp var cache = new FusionCache(new FusionCacheOptions() { DefaultEntryOptions = new FusionCacheEntryOptions { Duration = TimeSpan.FromMinutes(2) } }); ``` Or, using DI, like this: ```csharp services.AddFusionCache() .WithDefaultEntryOptions(new FusionCacheEntryOptions { Duration = TimeSpan.FromMinutes(2) }) ; ``` Now, to get the product from the cache and, if not there, get it from the database in an optimized way and cache it for `30 sec` (overriding the default `2 min` we set above) simply do this: ```csharp var id = 42; cache.GetOrSet<Product>( $"product:{id}", _ => GetProductFromDb(id), TimeSpan.FromSeconds(30) ); ``` That's it 🎉 <details> <summary>Want a little bit more 😏 ?</summary> Now, imagine we want to do the same, but also: - set the **priority** of the cache item to `High` (mainly used in the underlying memory cache) - enable **fail-safe** for `2 hours`, to allow an expired value to be used again in case of problems with the database ([read more](docs/FailSafe.md)) - set a factory **soft timeout** of `100 ms`, to avoid too slow factories crumbling your application when there's a fallback value readily available ([read more](docs/Timeouts.md)) - set a factory **hard timeout** of `2 sec`, so that, even if there is no fallback value to use, you will not wait undefinitely but instead an exception will be thrown to let you handle it however you want ([read more](docs/Timeouts.md)) To do all of that we simply have to change the last line (reformatted for better readability): ```csharp cache.GetOrSet<Product>( $"product:{id}", _ => GetProductFromDb(id), // THIS IS WHERE THE MAGIC HAPPENS options => options .SetDuration(TimeSpan.FromSeconds(30)) .SetPriority(CacheItemPriority.High) .SetFailSafe(true, TimeSpan.FromHours(2)) .SetFactoryTimeouts(TimeSpan.FromMilliseconds(100), TimeSpan.FromSeconds(2)) ); ``` Basically, on top of specifying the *cache key* and the *factory*, instead of specifying just a *duration* as a `TimeSpan` we specify a `FusionCacheEntryOptions` object - which contains all the options needed to control the behavior of FusionCache during each operation - in the form of a lambda that automatically duplicates the default entry options defined before (to copy all our defaults) while giving us a chance to modify it as we like for this specific call. Now let's say we really like these set of options (*priority*, *fail-safe* and *factory timeouts*) and we want them to be the overall defaults, while keeping the ability to change something on a per-call basis (like the *duration*). To do that we simply **move** the customization of the entry options where we created the `DefaultEntryOptions`, by changing it to something like this (the same is true for the DI way): ```csharp var cache = new FusionCache(new FusionCacheOptions() { DefaultEntryOptions = new FusionCacheEntryOptions() .SetDuration(TimeSpan.FromMinutes(2)) .SetPriority(CacheItemPriority.High) .SetFailSafe(true, TimeSpan.FromHours(2)) .SetFactoryTimeouts(TimeSpan.FromMilliseconds(100), TimeSpan.FromSeconds(2)) }); ``` Now these options will serve as the **cache-wide default**, usable in every method call as a "starting point". Then, we just change our method call to simply this: ```csharp var id = 42; cache.GetOrSet<Product>( $"product:{id}", _ => GetProductFromDb(id), options => options.SetDuration(TimeSpan.FromSeconds(30)) ); ``` The `DefaultEntryOptions` we did set before will be duplicated and only the duration will be changed for this call. </details> ## **👩‍🏫 Step By Step** If you are in for a ride you can read a complete [step by step example](docs/StepByStep.md) of why a cache is useful, why FusionCache could be even more so, how to apply most of the options available and what **results** you can expect to obtain. <div style="text-align:center;">  </div> ## 🖥️ Simulator Distributed systems are, in general, quite complex to understand. When using FusionCache with the [distributed cache](docs/CacheLevels.md), the [backplane](docs/Backplane.md) and [auto-recovery](docs/AutoRecovery.md) the Simulator can help us **seeing** the whole picture. [](docs/Simulator.md) ## 🧰 Supported Platforms FusionCache targets `.NET Standard 2.0` so any compatible .NET implementation is fine: this means `.NET Framework` (the old one), `.NET Core 2+` and `.NET 5/6/7/8+` (the new ones), `Mono` 5.4+ and more (see [here](https://docs.microsoft.com/en-us/dotnet/standard/net-standard#net-implementation-support) for a complete rundown). **NOTE**: if you are running on **.NET Framework 4.6.1** and want to use **.NET Standard** packages Microsoft suggests to upgrade to .NET Framework 4.7.2 or higher (see the [.NET Standard Documentation](https://docs.microsoft.com/en-us/dotnet/standard/net-standard#net-implementation-support)) to avoid some known dependency issues. ## 🆎 Comparison There are various alternatives out there with different features, different performance characteristics (cpu/memory) and in general a different set of pros/cons. A [feature comparison](docs/Comparison.md) between existing .NET caching solutions may help you choose which one to use. ## 💰 Support Nothing to do here. After years of using a lot of open source stuff for free, this is just me trying to give something back to the community. If you really want to talk about money, please consider making **❤ a donation to a good cause** of your choosing, and let me know about that. ## 💼 Is it Production Ready :tm: ? Yes! FusionCache is being used **in production** on **real world projects** for years, happily handling millions and millions of requests. Considering that the FusionCache packages have been downloaded more than **6 million times** (thanks everybody!) it may very well be used even more. Oh, and it is being used in products by Microsoft itself, like [Data API Builder]()! ## 😍 Are you using it? If you find FusionCache useful please [let me know](https://github.com/ZiggyCreatures/FusionCache/discussions/new?category=show-and-tell&title=I%27m%20using%20FusionCache!&body=%23%23%20Scenario%0ADescribe%20how%20you%20are%20using%20FusionCache:%20commercial%20product,%20oss%20project,%20monolith,%20microservice,%20web,%20mobile%20app,%20CLI,%20etc%0A%0A%23%23%20Liked%0AWhat%20you%20liked,%20features,%20docs%20or%20anything%0A%0A%23%23%20Unliked/Missing%0AThings%20you%20didn%27t%20like%20or%20felt%20was%20missing%0A%0A%23%23%20Closing%20Thoughts%0AAny%20closing%20thoughts), I'm really interested! This is the only way for me to know how it is helping people. ", Assign "at most 3 tags" to the expected json: {"id":"7792","tags":[]} "only from the tags list I provide: [{"id":77,"name":"3d"},{"id":89,"name":"agent"},{"id":17,"name":"ai"},{"id":54,"name":"algorithm"},{"id":24,"name":"api"},{"id":44,"name":"authentication"},{"id":3,"name":"aws"},{"id":27,"name":"backend"},{"id":60,"name":"benchmark"},{"id":72,"name":"best-practices"},{"id":39,"name":"bitcoin"},{"id":37,"name":"blockchain"},{"id":1,"name":"blog"},{"id":45,"name":"bundler"},{"id":58,"name":"cache"},{"id":21,"name":"chat"},{"id":49,"name":"cicd"},{"id":4,"name":"cli"},{"id":64,"name":"cloud-native"},{"id":48,"name":"cms"},{"id":61,"name":"compiler"},{"id":68,"name":"containerization"},{"id":92,"name":"crm"},{"id":34,"name":"data"},{"id":47,"name":"database"},{"id":8,"name":"declarative-gui "},{"id":9,"name":"deploy-tool"},{"id":53,"name":"desktop-app"},{"id":6,"name":"dev-exp-lib"},{"id":59,"name":"dev-tool"},{"id":13,"name":"ecommerce"},{"id":26,"name":"editor"},{"id":66,"name":"emulator"},{"id":62,"name":"filesystem"},{"id":80,"name":"finance"},{"id":15,"name":"firmware"},{"id":73,"name":"for-fun"},{"id":2,"name":"framework"},{"id":11,"name":"frontend"},{"id":22,"name":"game"},{"id":81,"name":"game-engine "},{"id":23,"name":"graphql"},{"id":84,"name":"gui"},{"id":91,"name":"http"},{"id":5,"name":"http-client"},{"id":51,"name":"iac"},{"id":30,"name":"ide"},{"id":78,"name":"iot"},{"id":40,"name":"json"},{"id":83,"name":"julian"},{"id":38,"name":"k8s"},{"id":31,"name":"language"},{"id":10,"name":"learning-resource"},{"id":33,"name":"lib"},{"id":41,"name":"linter"},{"id":28,"name":"lms"},{"id":16,"name":"logging"},{"id":76,"name":"low-code"},{"id":90,"name":"message-queue"},{"id":42,"name":"mobile-app"},{"id":18,"name":"monitoring"},{"id":36,"name":"networking"},{"id":7,"name":"node-version"},{"id":55,"name":"nosql"},{"id":57,"name":"observability"},{"id":46,"name":"orm"},{"id":52,"name":"os"},{"id":14,"name":"parser"},{"id":74,"name":"react"},{"id":82,"name":"real-time"},{"id":56,"name":"robot"},{"id":65,"name":"runtime"},{"id":32,"name":"sdk"},{"id":71,"name":"search"},{"id":63,"name":"secrets"},{"id":25,"name":"security"},{"id":85,"name":"server"},{"id":86,"name":"serverless"},{"id":70,"name":"storage"},{"id":75,"name":"system-design"},{"id":79,"name":"terminal"},{"id":29,"name":"testing"},{"id":12,"name":"ui"},{"id":50,"name":"ux"},{"id":88,"name":"video"},{"id":20,"name":"web-app"},{"id":35,"name":"web-server"},{"id":43,"name":"webassembly"},{"id":69,"name":"workflow"},{"id":87,"name":"yaml"}]" returns me the "expected json"