// Licensed to the Apache Software Foundation (ASF) under one or more
// contributor license agreements.  See the NOTICE file distributed with
// this work for additional information regarding copyright ownership.
// The ASF licenses this file to You under the Apache License, Version 2.0
// (the "License"); you may not use this file except in compliance with
// the License.  You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
= Ignite.NET Logging

== Overview
By default, Ignite uses underlying the Java log4j logging system. Log messages from both .NET and Java are recorded there.
You can also write to this log via an `IIgnite.Logger` instance:

[tabs]
--
tab:C#[]
[source,csharp]
----
var ignite = Ignition.Start();
ignite.Logger.Info("Hello World!");
----
--

`LoggerExtensions` class provides convenient shortcuts for `ILogger.Log` method.

== Custom Logger

You can provide a logger implementation via the `IgniteConfiguration.Logger` and `ILogger` interface.
Messages from both .NET and Java will be redirected there.

[tabs]
--
tab:C#[]
[source,csharp]
----
var cfg = new IgniteConfiguration
{
  Logger = new MemoryLogger()
}

var ignite = Ignition.Start();

class MemoryLogger : ILogger
{
  // Logger can be called from multiple threads, use concurrent collection
  private readonly ConcurrentBag<string> _messages = new ConcurrentBag<string>();

  public void Log(LogLevel level, string message, object[] args,
                  IFormatProvider formatProvider, string category,
                  string nativeErrorInfo, Exception ex)
  {
    _messages.Add(message);
  }

  public bool IsEnabled(LogLevel level)
  {
    // Accept any level.
    return true;
  }
}
----
tab:app.config[]
[source,xml]
----
<igniteConfiguration>
<logger type="MyNamespace.MemoryLogger, MyAssembly" />
</igniteConfiguration>
----
--

== NLog & log4net Loggers

Ignite.NET provides `ILogger` implementations for http://nlog-project.org/[NLog, window=_blank] and https://logging.apache.org/log4net/[Apache log4net, window=_blank].
They are included in the binary package (`Apache.Ignite.NLog.dll` and `Apache.Ignite.Log4Net.dll`) and can be installed via NuGet:

* `Install-Package Apache.Ignite.NLog`
* `Install-Package Apache.Ignite.Log4Net`

NLog and Log4Net use statically defined configuration, so there is nothing to configure in Ignite besides `IgniteConfiguration.Logger`:

[tabs]
--
tab:C#[]
[source,csharp]
----
var cfg = new IgniteConfiguration
{
  Logger = new IgniteNLogLogger()  // or IgniteLog4NetLogger
}

var ignite = Ignition.Start();
----
tab:app.config[]
[source,xml]
----
<igniteConfiguration>
  <logger type="Apache.Ignite.NLog.IgniteNLogLogger, Apache.Ignite.NLog" />
</igniteConfiguration>
----
--

A simple file-based logging with NLog can be set up like this:

[tabs]
--
tab:C#[]
[source,csharp]
----
var nlogConfig = new LoggingConfiguration();

var fileTarget = new FileTarget
{
  FileName = "ignite_nlog.log"
};
nlogConfig.AddTarget("logfile", fileTarget);

nlogConfig.LoggingRules.Add(new LoggingRule("*", LogLevel.Trace, fileTarget));
LogManager.Configuration = nlogConfig;

var igniteConfig = new IgniteConfiguration
{
  Logger = new IgniteNLogLogger()
};
Ignition.Start(igniteConfig);
----
--