Audit.NET 27.3.1

Audit.NET

USAGE | OUTPUT | CUSTOMIZATION | DATA PROVIDERS | CREATION POLICY | CONFIGURATION | EXTENSIONS

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An extensible framework to audit executing operations in .NET and .NET Core.

Generate audit logs with evidence for reconstruction and examination of activities that have affected specific operations or procedures.

With Audit.NET you can generate tracking information about operations being executed. It gathers environmental information such as the caller user ID, machine name, method name, and exceptions, including execution time and exposing an extensible mechanism to enrich the logs and handle the audit output.

• Interaction extensions to audit different systems are provided, such as Entity Framework, MVC, WebAPI, WCF, File System, SignalR, MongoClient and HttpClient.

• Output extensions are provided to log to JSON Files, Event Log, SQL, MySQL, PostgreSQL, RavenDB, MongoDB, AzureBlob, AzureTables, AzureCosmos, Redis, Elasticsearch, DynamoDB, UDP datagrams, Channels and more.

• Output wrappers are included to facilitate the encapsulation of other Data Providers for diverse purposes, like resilience or lazy instantiation, such as Polly, Lazy, Deferred and Conditional.

NuGet

To install the package run the following command on the Package Manager Console:

PM> Install-Package Audit.NET

Changelog

Check the CHANGELOG.md file.

Introduction

The Audit Scope and Audit Event are the central objects of this framework.

Audit Scope

The AuditScope serves as the central object in this framework, representing the scope of an audited operation or event. It acts as a context for auditing, capturing pertinent details like the start time, involved entities, and any additional custom information. Essentially, the AuditScope encapsulates an AuditEvent, controlling its life cycle.

The AuditScope is a disposable object, commonly utilized within a using statement to ensure proper finalization and recording of audit information upon exiting the scope.

See the audit scope statechart.

Audit Event

The AuditEvent functions as an extensible information container that captures the details of the audited operation, is the representation of the audited information within an Audit Scope. It includes details about the audited operation, such as the event type, timestamp, execution duration, and any custom fields or properties.

The AuditEvent is typically serialized into a format suitable for storage or transmission, such as JSON.

The audit events are stored using a Data Provider. You can use one of the available data providers or implement your own.

Audit Scope Factory

The preferred method for creating audit scopes is by using an IAuditScopeFactory instance. This approach ensures a centralized and consistent configuration for all audit scopes.

var factory = new AuditScopeFactory();
using var scope = factory.Create(new AuditScopeOptions(...));
...

If you're using a DI container, you can register the IAuditScopeFactory as a service and inject it into your classes. The default implementation of IAuditScopeFactory is provided by the AuditScopeFactory class.

services.AddScoped<IAuditScopeFactory, AuditScopeFactory>();

Then you can inject the IAuditScopeFactory into your classes to create audit scopes:

public class MyService
{
  private readonly IAuditScopeFactory _auditScopeFactory;

  public MyService(IAuditScopeFactory auditScopeFactory)
  {
    _auditScopeFactory = auditScopeFactory;
  }

  public void MyMethod()
  {
    using var scope = _auditScopeFactory.Create(new AuditScopeOptions(...));
    ...
  }
}

You can also implement your own IAuditScopeFactory to customize the creation of audit scopes. The recommended approach is to inherit from the AuditScopeFactory class. By overriding the OnConfiguring and OnScopeCreated methods, you can configure the audit scope options before creation and customize the audit scope after creation respectively.

For example:

public class MyAuditScopeFactory : AuditScopeFactory
{
  private readonly IMyService _myService;
  public MyAuditScopeFactory(IMyService myService)
  {
    _myService = myService;
  }

  public override void OnConfiguring(AuditScopeOptions options)
  {
    // Set the data provider to use
    options.DataProvider = new SqlDataProvider(...);
  }

  public override void OnScopeCreated(AuditScope auditScope)
  {
    // Add a custom field to the audit scope
    auditScope.SetCustomField("CustomId", _myService.GetId());
  }
}

Several extensions for generating audit events, such as Audit.EntityFramework.Core, Audit.WebApi.Core, Audit.Mvc.Core, and Audit.SignalR, will automatically attempt to resolve the IAuditScopeFactory and AuditDataProvider instances from the service provider.

Support for older .NET frameworks

Beginning with version 23.0.0, this library and its extensions have discontinued support for older .NET Framework and Entity Framework (versions that lost Microsoft support before 2023).

For reference, please consult the following links:

• .NET Core Support Policy
• Entity Framework Core releases

This library and its extensions will maintain support for the following minimum .NET framework versions:

• .NET Framework 4.6.2 (net462)
• .NET Standard 2.0 (netstandard2.0)
• .NET 6 (net6.0)

Usage

The Audit Scope is the central object of this framework. It encapsulates an audit event, controlling its life cycle. The Audit Event is an extensible information container of an audited operation.

There are several ways to create an Audit Scope:

• Calling the Create() / CreateAsync() methods of an AuditScopeFactory instance. This is the recommended approach. For example:

  var scope = auditScopeFactory.Create(new AuditScopeOptions(...));
  

• Using the overloads of the static methods Create() / CreateAsync() on AuditScope, for example:

  var scope = AuditScope.Create(new AuditScopeOptions()
  {
    EventType = "Order:Update",
    TargetGetter = () => order,
    ExtraFields = new { MyProperty = "value" }
  });
  

• Using the provided fluent API, for example:

  var scope = AuditScope.Create(_ => _
      .EventType("Order:Update")
      .ExtraFields(new { MyProperty = "value" })
      .Target(() => order));
  

AuditScope options

Option	Type	Description
EventType	string	A string representing the type of the event
TargetGetter	Func<object>	Target object getter (a func that returns the object to track)
ExtraFields	object	Anonymous object that contains additional fields to be merged into the audit event
DataProvider	AuditDataProvider	The data provider to use. Defaults to the DataProvider configured on Audit.Core.Configuration.DataProvider
CreationPolicy	EventCreationPolicy	The creation policy to use. Default is InsertOnEnd
IsCreateAndSave	bool	Value indicating whether this scope should be immediately ended and saved after creation. Default is false
AuditEvent	AuditEvent	Custom initial audit event to use. By default it will create a new instance of basic AuditEvent
SkipExtraFrames	int	Value used to indicate how many frames in the stack should be skipped to determine the calling method. Default is 0
CallingMethod	MethodBase	Specific calling method to store on the event. Default is to use the calling stack to determine the calling method.
Items	Dictionary<string, object>	A dictionary of items that can be used to store additional information on the scope, accessible from the AuditScope instance.

For instance, consider the following code to cancel an order that you want to audit:

Order order = Db.GetOrder(orderId);
order.Status = -1;
order.OrderItems = null;
order = Db.OrderUpdate(order);

To audit this operation, you can wrap the code in a using block that initializes an AuditScope, specifying the target object to monitor:

Order order = Db.GetOrder(orderId);
using (AuditScope.Create("Order:Update", () => order))
{
  order.Status = -1;
  order.OrderItems = null;
  order = Db.OrderUpdate(order);
}

Note

Using a using block is not required, but it streamlines the syntax when auditing a single code block. It also enables automatic exception detection and duration calculation by implicitly saving the event upon disposal.

Note

When using the extensions that logs interactions with different systems, like Audit.EntityFramework, Audit.WebApi, etc. you don't need to explicitly create the AuditScope or AuditEvent, they are created internally by the extension.

Simple logging

If you are not tracking an object or the duration of an event, you can use the Log shortcut method that logs an event immediately. For example:

AuditScope.Log("Event Type", new { ExtraField = "extra value" });

Manual Saving

You can control the creation and saving logic, by creating a manual AuditScope. For example to log a pair of Start/End method calls as a single event:

public class SomethingThatStartsAndEnds
{
    private AuditScope auditScope;

    public int Status { get; set; }

    public void Start()
    {
        // Create a manual scope
        auditScope = AuditScope.Create(new AuditScopeOptions()
        {
            EventType = "MyEvent",
            TargetGetter = () => this.Status,
            CreationPolicy = EventCreationPolicy.Manual
        });
    }

    public void End()
    {
        // Save the event
        auditScope.Save();  
        // Discard to avoid further saving
        auditScope.Discard();
    }
}

For more information about the EventCreationPolicy please see Event Creation Policy section.

Output

The library will generate an output (AuditEvent) for each operation, including:

• Tracked object's state before and after the operation.
• Execution time and duration.
• Environment information such as user, machine, domain, locale, etc.
• Comments and Custom Fields provided.

An example of the output in JSON:

{
    "EventType": "Order:Update",
    "Environment": {
        "UserName": "Federico",
        "MachineName": "HP",
        "DomainName": "HP",
        "CallingMethodName": "Audit.UnitTest.AuditTests.TestUpdate()",
        "Exception": null,
        "Culture": "en-GB"
    },
    "Activity": {
        "StartTimeUtc": "2023-12-01T17:36:52.2256288Z",
	"SpanId": "23a93b9e8cbc457f",
	"TraceId": "2d3e5e90f790c7d2274d9bb047531f66",
	"ParentId": "0000000000000000",
	"Operation": "Update"
    },
    "StartDate": "2016-08-23T11:33:14.653191Z",
    "EndDate": "2016-08-23T11:33:23.1820786Z",
    "Duration": 8529,
    "Target": {
        "Type": "Order",
        "Old": {
            "OrderId": "39dc0d86-d5fc-4d2e-b918-fb1a97710c99",
            "Status": 2,
            "OrderItems": [{
                "Sku": "1002",
                "Quantity": 3.0
            }]
        },
        "New": {
            "OrderId": "39dc0d86-d5fc-4d2e-b918-fb1a97710c99",
            "Status": -1,
            "OrderItems": null
        }
    }
}

Output details

The following tables describe the output fields:

• AuditEvent object

Field Name	Type	Description
EventType	string	User-defined string to group the events
Environment	Environment	Contains information about the execution environment
StartDate	DateTime	Date and time when the event has started
EndDate	DateTime	Date and time when the event has ended
Duration	integer	Duration of the event in milliseconds
Target	Target	User-defined tracked object
Comments	Array of strings	User-defined comments
CustomFields	Dictionary	User-defined custom fields

• Environment object

Field Name	Type	Description
UserName	string	Current logged user name
MachineName	string	Executing machine name
DomainName	string	Current user domain
CallingMethodName	string	Calling method signature information
StackTrace	string	The full stack trace at the moment of the audit scope creation (NULL unless it's enabled by configuration)
Exception	string	Indicates if an Exception has been detected (NULL if no exception has been thrown)
Culture	string	Current culture identifier

• Target object

Field Name	Type	Description
Type	string	Tracked object type name
Old	Object	Value of the tracked object at the beginning of the event
New	Object	Value of the tracked object at the end of the event

Custom Fields and Comments

The AuditScope object provides two methods to extend the event output.

• Use SetCustomField() method to add any object as an extra field to the event.
• Use Comment() to add textual comments to the event's Comments array.

For example:

Order order = Db.GetOrder(orderId);
using (var audit = AuditScope.Create("Order:Update", () => order))
{
    audit.SetCustomField("ReferenceId", orderId);
    order.Status = -1;
    order = Db.OrderUpdate(order);
    audit.Comment("Status Updated to Cancelled");
}

You can also set Custom Fields when creating the AuditScope, by passing an anonymous object with the properties you want as extra fields. For example:

using (var audit = AuditScope.Create("Order:Update", () => order, new { ReferenceId = orderId }))
{
    order.Status = -1;
    order = Db.OrderUpdate(order);
    audit.Comment("Status Updated to Cancelled");
}

You can also access the Custom Fields directly from Event.CustomFields property of the scope. For example:

using (var audit = AuditScope.Create("Order:Update", () => order, new { ReferenceId = orderId }))
{
    audit.Event.CustomFields["ReferenceId"] = orderId;
}

Note

Custom fields are not limited to single properties, you can store any object as well, by default they will be JSON serialized.

Extending AuditEvent

Another way to enrich the event output is to create a class inheriting from the AuditEvent class, then you can pass an instance of your class to the AuditScope.Create method. For example:

public class YourAuditEvent : AuditEvent
{
    public Guid ReferenceId { get; set; } = Guid.NewGuid();
}

using (var scope = AuditScope.Create(new AuditScopeOptions { AuditEvent = new YourAuditEvent() }))
{
    //...
}

The output of the previous examples would be:

{
    "EventType": "Order:Update",
    "Environment": {
        "UserName": "Federico",
        "MachineName": "HP",
        "DomainName": "HP",
        "CallingMethodName": "Audit.UnitTest.AuditTests.TestUpdate()",
        "Exception": null,
        "Culture": "en-GB"
    },
    "Target": {
        "Type": "Order",
        "Old": {
            "OrderId": "39dc0d86-d5fc-4d2e-b918-fb1a97710c99",
            "Status": 2,
            
        },
        "New": {
            "OrderId": "39dc0d86-d5fc-4d2e-b918-fb1a97710c99",
            "Status": -1,
            
        }
    },
    "ReferenceId": "39dc0d86-d5fc-4d2e-b918-fb1a97710c99",           // <-- Custom Field
    "Comments": ["Status Updated to Cancelled"],                     // <-- Comments
    "StartDate": "2016-08-23T11:34:44.656101-05:00",
    "EndDate": "2016-08-23T11:34:55.1810821-05:00",
    "Duration": 8531
}

Discard option

The AuditScope object has a Discard() method to allow the user to discard an event. Discarding an event means it won't be saved.

For example, if you want to avoid saving the audit event under certain conditions:

using (var scope = AuditScope.Create(new AuditScopeOptions("SomeEvent", () => someTarget)))
{
    try
    {
        //some operation
        Critical.Operation();
    }
    catch (Exception ex)
    {
        //If an exception is thrown, discard the audit event
        scope.Discard();
    }
}

Data providers

A data provider (or storage sink) contains the logic to handle the audit event output, where you define what to do with the audit logs.

You can use one of the data providers included or inject your own mechanism by creating a class that inherits from AuditDataProvider and overrides its methods:

• InsertEvent: should store the event and return a unique ID.
• ReplaceEvent: should update an event given its ID. This method is only used for Creation Policies Manual or InsertOnStartReplaceOnEnd.

If your data provider will support asynchronous operations, you must also implement the following methods:

• InsertEventAsync: Asynchronous implementation of the InsertEvent method.
• ReplaceEventAsync: Asynchronous implementation of the ReplaceEvent method.

Also, if your data provider will support event retrieval, you should implement the following methods:

• GetEvent: Retrieves an event by id.
• GetEventAsync: Asynchronous implementation of the GetEvent method.

For example:

public class MyCustomDataProvider : AuditDataProvider
{
    public override object InsertEvent(AuditEvent auditEvent)
    {
        var fileName = $"Log{Guid.NewGuid()}.json";
        File.WriteAllText(fileName, auditEvent.ToJson());
        return fileName;
    }
    public override void ReplaceEvent(object eventId, AuditEvent auditEvent)
    {
        var fileName = eventId.ToString();
        File.WriteAllText(fileName, auditEvent.ToJson());
    }
    public override T GetEvent<T>(object eventId)
    {
        var fileName = eventId.ToString();
        return JsonConvert.DeserializeObject<T>(File.ReadAllText(fileName));
    }
    // async implementation:
    public override async Task<object> InsertEventAsync(AuditEvent auditEvent, CancellationToken cancellationToken = default)
    {
        var fileName = $"Log{Guid.NewGuid()}.json";
        await File.WriteAllTextAsync(fileName, auditEvent.ToJson(), cancellationToken);
        return fileName;
    }
    public override async Task ReplaceEventAsync(object eventId, AuditEvent auditEvent, CancellationToken cancellationToken = default)
    {
        var fileName = eventId.ToString();
        await File.WriteAllTextAsync(fileName, auditEvent.ToJson(), cancellationToken);
    }
    public override async Task<T> GetEventAsync<T>(object eventId, CancellationToken cancellationToken = default)
    {
        var fileName = eventId.ToString();
        return await GetFromFileAsync<T>(cancellationToken);
    }
}

Data provider selection

The data provider can be set globally for the entire application or per audit scope.

Note

If you don't specify a global data provider, it will default to a FileDataProvider that logs events as .json files into the current working directory.

To set the global data provider, assign the DataProvider property on the static Audit.Core.Configuration object, or call the fluent API Use(). For example:

Audit.Core.Configuration.DataProvider = new MyCustomDataProvider();

Or using the fluent API Use() method:

Audit.Core.Configuration.Setup()
  .Use(new MyCustomDataProvider());

To set the data provider per-scope, use the AuditScopeOptions when creating an AuditScope. For example:

var scope = AuditScope.Create(new AuditScopeOptions 
{ 
  DataProvider = new MyCustomDataProvider(), ... }
);

Every data provider is accompanied by a fluent API accessible during object construction or via its respective Use___() method. For instance, in the case of the SqlDataProvider:

var sqlDataProvider = new SqlDataProvider(_ => _
    .ConnectionString("your connection string")
    .TableName("your table name")
    .IdColumnName("your id column name")
    .JsonColumnName("your json column name"));

Audit.Core.Configuration.Setup()
  .UseSqlServer(_ => _
    .ConnectionString("your connection string")
    .TableName("your table name")
    .IdColumnName("your id column name")
    .JsonColumnName("your json column name"));

Data provider wrappers

A special type of Data Providers that allows wrapping other Data Provider with different purposes.

Dynamic data provider

As an alternative to creating a data provider class, you can define the mechanism at run time by using the DynamicDataProvider or DynamicAsyncDataProvider classes. For example:

Audit.Core.Configuration.Setup()
  .UseDynamicProvider(config => config
    .OnInsert(ev => Console.Write(ev.ToJson())));

For async operations, you should use the DynamicAsyncDataProvider, for example:

Audit.Core.Configuration.Setup()
  .UseDynamicAsyncProvider(config => config
    .OnInsert(async ev => await File.WriteAllTextAsync(filePath, ev.ToJson())));

Lazy Factory data provider

You can set the global data provider using a deferred instantiation technique, with a lazy factory method that will be called upon its initial utilization. For instance, in situations where dependency resolution is needed but not immediately accessible during initialization.

Allows to lazily instantiate the data provider to use. The data provider factory method will be called only once; the first time it's needed.

For example:

Audit.Core.Configuration.Setup()
    .UseLazyFactory(() => app.ApplicationServices.GetService<CustomDataProvider>());

Deferred Factory data provider

You can defer creating the data provider for each Audit Event until it is ready to be saved by using a deferred factory method. The factory method will be called for each audit event being saved.

For example:

var sqlDataProvider = new SqlDataProvider(config => config...);
var fileDataProvider = new FileDataProvider(config => config...);

Audit.Core.Configuration.Setup()
    .UseDeferredFactory(auditEvent => auditEvent is AuditEventWebApi ? sqlDataProvider : fileDataProvider);

Conditional data provider

Enables the configuration of different data providers based on conditions related to the audit event.

For example:

Configuration.DataProvider = new ConditionalDataProvider(config => config
  .When(auditEvent => auditEvent.EventType.Equals("A"), new MyCustomDataProvider())
  .When(auditEvent => auditEvent.EventType.Equals("B"), new SqlDataProvider())
  .Otherwise(new FileDataProvider()));

Polly data provider

Allows to define Polly resilience strategies to any Data Provider.

This is useful when you want to add resilience to your data provider, for example, to retry failed operations, or to add a circuit breaker.

For example:

Audit.Core.Configuration.Setup()
  .UsePolly(p => p
    .DataProvider(new SqlDataProvider(...))
    .WithResilience(resilience => resilience
      .AddRetry(new()
      {
        ShouldHandle = new PredicateBuilder().Handle<SqlException>(),
        MaxRetryAttempts = 2
      })));

For more information, please refer to the Audit.NET.Polly documentation.

Data providers included

The Data Providers included are summarized in the following table:

Type	Technology	Package / Class	Description	Configuration API
SQL	Amazon QLDB	Audit.NET.AmazonQLDB / AmazonQldbDataProvider	Store the audit events using Amazon QLDB.	.UseAmazonQldb()
SQL	Entity Framework	Audit.EntityFramework / EntityFrameworkDataProvider	Store EntityFramework audit events in the same EF context. (This data provider can only be used for Entity Framework audits)	.UseEntityFramework()
SQL	MySql	Audit.NET.MySql / MySqlDataProvider	Store the events as rows in a MySQL database table, in JSON format.	.UseMySql()
SQL	Postgre SQL	Audit.NET.PostgreSql / PostgreSqlDataProvider	Store the events as rows in a PostgreSQL database table, in JSON format.	.UsePostgreSql()
SQL	SQL Server	Audit.NET.SqlServer / SqlDataProvider	Store the events as rows in a MS SQL Table, in JSON format.	.UseSqlServer()
NoSQL	Azure Cosmos	Audit.NET.AzureCosmos / AzureCosmosDataProvider	Store the events in an Azure Cosmos DB container, in JSON format.	.UseAzureCosmos()
NoSQL	Azure Storage	Audit.NET.AzureStorageBlobs / AzureStorageBlobDataProvider	Store the events in an Azure Blob Storage container, in JSON format.	.UseAzureStorageBlobs()
NoSQL	Azure Tables	Audit.NET.AzureStorageTables / AzureStorageTableDataProvider	Store the events in an Azure Table Storage.	.UseAzureTableStorage()
NoSQL	Dynamo DB	Audit.NET.DynamoDB / DynamoDataProvider	Store audit events in Amazon DynamoDB™ tables.	.UseDynamoDB()
NoSQL	Elasticsearch	Audit.NET.Elasticsearch / ElasticsearchDataProvider	Store audit events in Elasticsearch indices.	.UseElasticsearch()
NoSQL	Kafka	Audit.NET.Kafka / KafkaDataProvider	Stream the audit events to Apache Kafka topics.	.UseKafka() / .UseKafka<TKey>()
NoSQL	Mongo DB	Audit.NET.MongoDB / MongoDataProvider	Store the events in a Mongo DB collection, in BSON format.	.UseMongoDB()
NoSQL	Raven DB	Audit.NET.RavenDB / RavenDbDataProvider	Store the events as documents in a Raven DB database table, in JSON format.	.UseRavenDB()
NoSQL	Redis	Audit.NET.Redis / RedisDataProvider	Store audit logs in Redis as Strings, Lists, SortedSets, Hashes, Streams or publish to a PubSub channel.	.UseRedis()
Local	Windows Event Log	Audit.NET / Audit.NET.EventLog.Core 7 EventLogDataProvider	Write the audit logs to the Windows EventLog.	.UseEventLogProvider()
Local	File System	Audit.NET / FileDataProvider	Store the audit logs as files. Dynamically configure the directory and path.	.UseFileLogProvider()
InMemory	In-Memory List	Audit.NET / InMemoryDataProvider	Store the audit logs in memory in a thread-safe list. Useful for testing purposes.	.UseInMemoryProvider()
InMemory	In-Memory Blocking Collection	Audit.NET / BlockingCollectionDataProvider	Store the audit events in a BlockingCollection that can be accessed by different threads to consume the events	.UseInMemoryBlockingCollectionProvider()
InMemory	In-Memory Channel	Audit.NET.Channels / ChannelDataProvider	Store the audit events in a Channel (from System.Threading.Channels) that can be accessed to consume the events	.UseInMemoryChannelProvider()
Logging	Log4net	Audit.NET.log4net / Log4netDataProvider	Store the audit events using Apache log4net™.	.UseLog4net()
Logging	NLog	Audit.NET.NLog / NLogDataProvider	Store the audit events using NLog.	.UseNLog()
Logging	Serilog	Audit.NET.Serilog / SerilogDataProvider	Store the audit events using Serilog™	.UseSerilog()
Network	UDP	Audit.NET.Udp / UdpDataProvider	Send Audit Logs as UDP datagrams to a network.	.UseUdp()
Wrapper	Conditional	Audit.NET / ConditionalDataProvider	Allows the configuration of different data providers based on conditions related to the audit event.	.UseConditional()
Wrapper	Deferred	Audit.NET / DeferredDataProvider	Facilitates delayed data provider instantiation via a factory method that is invoked for each Audit Event.	.UseDeferredFactory()
Wrapper	Dynamic	Audit.NET / DynamicDataProvider / DynamicAsyncDataProvider	Dynamically change the behavior at run-time. Define Insert and a Replace actions with lambda expressions.	.UseDynamicProvider() / .UseDynamicAsyncProvider()
Wrapper	Lazy	Audit.NET / LazyDataProvider	Facilitates delayed data provider instantiation via a factory method that is invoked just once, upon the initial need.	.UseLazyFactory()
Wrapper	Polly	Audit.NET.Polly / PollyDataProvider	Allows to define Polly resilience strategies to any Data Provider	.UsePolly()

Event Creation Policy

The audit scope allows configuration for invoking its data provider through different approaches:

• Insert on End (default): The audit event is recorded when the scope is disposed.

• Insert on Start, Replace on End: The initial state of the event is recorded upon scope creation, and the complete event information is updated when the scope is disposed.

• Insert on Start, Insert on End: Two versions of the event are recorded—one at scope creation and another at scope disposal.

• Manual: Event saving (insert or replace) must be explicitly triggered by calling the Save() method on the AuditScope.

The Creation Policy can be set on a per-scope basis. For example, to configure the policy explicitly to Manual:

using (var scope = AuditScope.Create(new AuditScopeOptions { CreationPolicy = EventCreationPolicy.Manual }))
{
    //...
    scope.Save();
}

Note

If you don't provide a Creation Policy when creating the AuditScope, the globally configured Creation Policy will be used (see the configuration section)

AuditScope statechart

The following is the internal state machine representation of the AuditScope object:

<img src="https://i.imgur.com/7WqGECe.png" alt="AuditScope statecart" />

Configuration

Data provider

To change the default data provider, set the static property DataProvider on Audit.Core.Configuration class. This should be done before the AuditScope creation, i.e. during application startup.

For example, to set your own provider as the default data provider:

Audit.Core.Configuration.DataProvider = new MyCustomDataProvider();

Note

If you don't specify a Data Provider, a default FileDataProvider will be used to write the events as .json files into the current working directory.

Creation Policy

To change the default creation policy, set the static property CreationPolicy on Audit.Core.Configuration class. This should be done before the AuditScope creation, i.e. during application startup.

For example, to set the default creation policy to Manual:

Audit.Core.Configuration.CreationPolicy = EventCreationPolicy.Manual;

Note

If you don't specify a Creation Policy, the default Insert on End will be used.

Custom Actions

You can configure Custom Actions to be executed across all Audit Scopes in your application. This allows you to globally modify behavior and data, intercepting scopes after they are created, before they are saved, or during disposal

Call the static AddCustomAction() method on Audit.Core.Configuration class to attach a custom action.

For example, to globally discard the events under a certain condition:

Audit.Core.Configuration.AddCustomAction(ActionType.OnScopeCreated, scope =>
{
    if (DateTime.Now.Hour >= 17)
    {
        scope.Discard();
        return false;
    }
    return true;
});

Note

The custom actions can return a boolean value to indicate if subsequent actions of the same type should be executed.

Or to add custom fields/comments globally to all scopes:

Audit.Core.Configuration.AddCustomAction(ActionType.OnEventSaving, scope =>
{
    if (scope.Event.Environment.Exception != null)
    {
        scope.SetCustomField("Oops", true);
    }
    scope.Comment("Saved at " + DateTime.Now);
});

Custom actions can also be asynchronous, for example:

Audit.Core.Configuration.AddCustomAction(ActionType.OnScopeCreated, async scope =>
{
    var result = await svcProvider.GetService<InfoService>().GetInfoAsync();
    scope.SetCustomField("Info", result);
});

The ActionType indicates when to perform the action. The allowed values are:

• OnScopeCreated: When the Audit Scope is being created, before any saving. This is executed once per Audit Scope.
• OnEventSaving: When an Audit Scope's Event is about to be saved.
• OnEventSaved: After an Audit Scope's Event is saved.
• OnScopeDisposed: When an Audit Scope is disposed.

Stack Trace

To include the stack trace details into the event environment, ensure that the IncludeStackTrace configuration is set to true. Default is false.

Audit.Core.Configuration.IncludeStackTrace = true;

or

Audit.Core.Configuration.Setup()
    .IncludeStackTrace();

Activity Trace

To include the current activity trace details from System.Diagnostics.Activity API into the event, ensure that the IncludeActivityTrace configuration is set to true. The default is false.

It will include the current Activity operation name, ID, and StartTime, along with associated Tags and Events.

Audit.Core.Configuration.IncludeActivityTrace = true;

or

Audit.Core.Configuration.Setup()
    .IncludeActivityTrace();

To create and start a new distributed activity trace, you can use the StartActivityTrace configuration:

Audit.Core.Configuration.Setup()
    .StartActivityTrace();

Global switch off

You can disable audit logging by setting the static property Configuration.AuditDisabled to true. The audit events are globally ignored while this flag is set. For example to disable the audits on certain environments:

if (environment.IsDevelopment())
{
    Audit.Core.Configuration.AuditDisabled = true;
}

Global serialization settings

Most of the data providers serialize audit events in JSON format. Audit.NET uses System.Text.Json by default for the serialization and deserialization of audit events.

If you want to change the behavior, you can change the settings via the static property Configuration.JsonSettings.

For example:

Audit.Core.Configuration.JsonSettings = new JsonSerializerOptions
{
    DefaultIgnoreCondition = JsonIgnoreCondition.WhenWritingDefault,
    AllowTrailingCommas = true
};

Custom serialization mechanism

If you want to use a custom JSON serialization mechanism for the Audit Events, you can create a class implementing IJsonAdapter and assign it to the static property Configuration.JsonAdapter.

For example:

Audit.Core.Configuration.JsonAdapter = new MyCustomAdapter(); 

Or by using the fluent API:

Audit.Core.Configuration.Setup()
    .JsonAdapter<MyCustomAdapter>()
    ...

Note

Take into account that some of the AuditEvent properties rely on attribute decoration for serialization and deserialization. The recommendation is to use the default adapter and, when needed, use the Newtonsoft Json adapter provided (see next section).

Alternative serialization mechanism

This library offers the option to configure an alternative JSON serialization mechanism through the following adapter:

• Audit.NET.JsonNewtonsoftAdapter

  Use this when you prefer employing Newtonsoft.Json as the serialization mechanism.

  Assign an instance of JsonNewtonsoftAdapter to the static configuration property Configuration.JsonAdapter. For example:

  var settings = new JsonSerializerSettings()
  {
      TypeNameHandling = TypeNameHandling.All
  };
  Audit.Core.Configuration.JsonAdapter = new JsonNewtonsoftAdapter(settings);
  

  Alternatively, you can use the fluent configuration API with the JsonNewtonsoftAdapter() method, like this:

  Audit.Core.Configuration.Setup()
      .JsonNewtonsoftAdapter(settings)
      ...
  

  NOTE: This JsonNewtonsoftAdapter takes into account JsonExtensionDataAttribute and JsonIgnoreAttribute decorators from both System.Text.Json and Newtonsoft.Json, so the Audit Events will be properly serialized.

Configuration Fluent API

Alternatively to the properties/methods mentioned before, you can configure the library using a convenient Fluent API provided by the method Audit.Core.Configuration.Setup(), this is the most straightforward way to configure the library.

For example, to set the FileLog Provider with its default settings using a Manual creation policy:

Audit.Core.Configuration.Setup
    .IncludeStackTrace()
    .IncludeActivityTrace()
    .UseFileLogProvider()
    .WithCreationPolicy(EventCreationPolicy.Manual);

Configuration examples

File log provider with dynamic directory path and filename:

Audit.Core.Configuration.Setup()
    .UseFileLogProvider(config => config
        .DirectoryBuilder(_ => $@"C:\Logs\{DateTime.Now:yyyy-MM-dd}")
        .FilenameBuilder(auditEvent => $"{auditEvent.Environment.UserName}_{DateTime.Now.Ticks}.json"));

File log provider with an InsertOnStart-ReplaceOnEnd creation policy, and a global custom field set in a custom action:

Audit.Core.Configuration.Setup()
    .UseFileLogProvider(config => config
        .FilenamePrefix("Event_")
        .Directory(@"C:\AuditLogs\1"))
    .WithCreationPolicy(EventCreationPolicy.InsertOnStartReplaceOnEnd)
    .WithAction(x => x.OnScopeCreated(scope => scope.SetCustomField("ApplicationId", "MyApplication")));

Event log provider with an InsertOnEnd creation policy:

Audit.Core.Configuration.Setup()
    .UseEventLogProvider(config => config
        .SourcePath("My Audited Application")
        .LogName("Application"))
    .WithCreationPolicy(EventCreationPolicy.InsertOnEnd);

Dynamic provider to log to the console:

Audit.Core.Configuration.Setup()
    .UseDynamicProvider(config => config
        .OnInsert(ev => Console.WriteLine("{0}: {1}->{2}", ev.StartDate, ev.Environment.UserName, ev.EventType)));

Multiple providers with conditional logic:

var sqlDataProvider = new SqlDataProvider(sql => sql.ConnectionString(CnnString).TableName("Logs"));
var fileDataProvider = new FileDataProvider(file => file.Directory(@"C:\logs"));

Audit.Core.Configuration.Setup()
    .UseConditional(c => c
        .When(ev => ev.EventType == "API", sqlDataProvider)
        .Otherwise(fileDataProvider));

---

Extensions

The following packages are extensions to log interactions with different systems such as MVC, WebApi, WCF, and Entity Framework:

<a></a>	Package	Description
<img src="https://i.imgur.com/hVMM5WF.png" alt="icon" width="90"/>	Audit.DynamicProxy	Generate detailed audit logs for any class without changing its code by using a proxy.
<img src="https://i.imgur.com/wdVHFoc.png" alt="icon" width="90"/>	Audit.EntityFramework	Generate detailed audit logs for saving operations on Entity Framework, by inheriting from a provided DbContext or IdentityDbContext. Includes support for EF 6 and EF 7 (EF Core).
<img src="https://i.imgur.com/Fn4thn0.png" alt="icon" width="90"/>	Audit.FileSystem	Generate audit logs by intercepting file system events via FileSystemWatcher.
<img src="https://i.imgur.com/8lV5DRk.png" alt="icon" width="90" />	Audit.HttpClient	Generate detailed client-side audit logs for HttpClient REST calls, by configuring a provided message handler.
<img src="https://i.imgur.com/ap6CeoG.png" alt="icon" width="90"/>	Audit.MVC	Generate detailed audit logs by decorating MVC Actions and Controllers with an action filter attribute. Includes support for ASP.NET Core MVC.
<img src="https://i.imgur.com/GB2e52X.jpg" alt="icon" width="90"/>	Audit.SignalR	Generate audit logs for SignalR and SignalR Core invocations by intercepting the hub processing
<img src="https://i.imgur.com/p6knit4.png" alt="icon" width="90" />	Audit.WCF	Generate detailed server-side audit logs for Windows Communication Foundation (WCF) service calls, by configuring a provided behavior.
<img src="https://i.imgur.com/p6knit4.png" alt="icon" width="90" />	Audit.WCF.Client	Generate detailed client-side audit logs for Windows Communication Foundation (WCF) service calls, by configuring a provided behavior.
<img src="https://i.imgur.com/9go2b0f.png" alt="icon" width="90"/>	Audit.WebApi	Generate detailed audit logs by decorating Web API Methods and Controllers with an action filter attribute, or by using a middleware. Includes support for ASP.NET Core.
<img src="https://i.imgur.com/1nMVLQo.png" alt="icon" width="90"/>	Audit.MongoClient	Generate detailed audit logs by adding a Command Event Subscriber into the configuration of the MongoDB Driver.

Data providers

A Data Provider (or Storage Provider) is a component responsible for handling how audit event data is stored or processed. The purpose of the Data Provider is to manage the persistence of audit logs once an audit event is triggered and captured. The Data Provider defines how the Audit Event is saved.

Audit.NET offers a range of built-in Data Providers for various storage solutions, including File System, Event Log, InMemory List, and InMemory Blocking Collection.

Moreover, several Data Provider Wrappers are available to encapsulate other Data Providers for various purposes, such as resilience and lazy instantiation. Examples include Polly, Lazy, Deferred, and Conditional.

In addition, a variety of other Data Providers are available through separate packages, as shown below:

<a></a>	Package	Description
<img width="80" src="https://unpkg.com/simple-icons@v11/icons/amazondynamodb.svg" />	Audit.NET.AmazonQLDB	Store the audit events in Amazon QLDB (Quantum Ledger Database).
<img width="80" src="https://unpkg.com/simple-icons@v11/icons/microsoftazure.svg" />	Audit.NET.AzureCosmos	Store the events in an Azure Cosmos DB container, in JSON format.
<img width="80" src="https://unpkg.com/simple-icons@v11/icons/microsoftazure.svg" />	Audit.NET.AzureStorage	Store the events in an Azure Blob Storage container or an Azure Table using the legacy client WindowsAzure.Storage.
<img width="80" src="https://unpkg.com/simple-icons@v11/icons/microsoftazure.svg" />	Audit.NET.AzureStorageBlobs	Store the events in an Azure Blob Storage container using the latest client Azure.Storage.Blobs.
<img width="80" src="https://unpkg.com/simple-icons@v11/icons/microsoftazure.svg" />	Audit.NET.AzureStorageTables	Store the events in an Azure Table Storage using the latest client Azure.Data.Tables.
<img width="80" src="https://unpkg.com/simple-icons@v11/icons/csharp.svg" />	Audit.NET.Channels	Store the audit events in a Channel (from System.Threading.Channels) that can be accessed to consume the events.
<img width="80" src="https://unpkg.com/simple-icons@v11/icons/amazondynamodb.svg" />	Audit.NET.DynamoDB	Store the audit events in Amazon DynamoDB tables.
<img width="80" src="https://unpkg.com/simple-icons@v11/icons/elasticsearch.svg" />	Audit.NET.Elasticsearch	Store the audit events in Elasticsearch indices.
<img width="80" src="https://unpkg.com/simple-icons@v11/icons/apachekafka.svg" />	Audit.NET.Kafka	Stream the audit events to an Apache Kafka server.
<img width="80" src="https://unpkg.com/simple-icons@v11/icons/csharp.svg" />	Audit.NET.log4net	Store the audit events using Apache log4net™.
<img width="80" src="https://unpkg.com/simple-icons@v11/icons/mongodb.svg" />	Audit.NET.MongoDB	Store the events in a Mongo DB Collection, in BSON format.
<img width="80" src="https://unpkg.com/simple-icons@v11/icons/mysql.svg" />	Audit.NET.MySql	Store the events as rows in MySQL database, in JSON format.
<img width="80" src="https://unpkg.com/simple-icons@v11/icons/csharp.svg" />	Audit.NET.NLog	Store the audit events using NLog™.
<img width="80" src="https://unpkg.com/simple-icons@v11/icons/csharp.svg" />	Audit.NET.Polly	Define Polly resiliencie strategies to any data provider.
<img width="80" src="https://unpkg.com/simple-icons@v11/icons/postgresql.svg" />	Audit.NET.PostgreSql	Store the events as rows in a PostgreSQL database, in JSON format.
<img width="80" src="https://unpkg.com/simple-icons@v11/icons/csharp.svg" />	Audit.NET.RavenDB	Store the events as documents in a Raven DB database, in JSON format.
<img width="80" src="https://unpkg.com/simple-icons@v11/icons/redis.svg" />	Audit.NET.Redis	Store Audit Logs in a Redis database as String, List, Hash, Sorted Set, Streams or publishing to a Redis PubSub channel.
<img width="80" src="https://unpkg.com/simple-icons@v11/icons/microsoftsqlserver.svg" />	Audit.NET.SqlServer	Store the events as rows in a SQL Table, in JSON format.
<img width="80" src="https://unpkg.com/simple-icons@v11/icons/csharp.svg" />	Audit.NET.Serilog	Store the audit events using Serilog™
<img width="80" src="https://unpkg.com/simple-icons@v11/icons/csharp.svg" />	Audit.NET.Udp	Send audit events as UDP datagrams to a network.

Change Log

For detailed information on changes in the new release refer to the change log.

Contribute

If you like this project please contribute in any of the following ways:

• Sponsoring this project.
• Star this project on GitHub.
• Request a new feature or expose any bug you found by creating a new issue.
• Ask any questions about the library on StackOverflow.
• Subscribe to and use the Gitter Audit.NET channel.
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