# Configuration

This page describes approaches to configuration employed in Vostok.Logging.

### Composing loggers hierarchy

There's no such thing as a log factory or log provider: there are just [ILog](https://github.com/vostok/logging.abstractions/blob/master/Vostok.Logging.Abstractions/ILog.cs) instances, and the only way to get one initially is to instantiate one of the available [implementations](https://vostok.gitbook.io/logging/implementations) in code. Everything else is achieved with decorator-based extensions and interface methods:

* [Combining](https://vostok.gitbook.io/logging/how-to-guides/combining-multiple-logs) multiple logs into one.
* [Filtering](https://vostok.gitbook.io/logging/how-to-guides/filtering-events-by-level) incoming events.
* [Enriching](https://vostok.gitbook.io/logging/how-to-guides/enriching-events-with-custom-properties) incoming events with properties.
* Obtaining log instances tied to specific [source context](https://vostok.gitbook.io/logging/concepts/source-context).

This approach may look unfamiliar to prior [log4net](https://logging.apache.org/log4net/) users experienced with [XML configuration files](https://logging.apache.org/log4net/release/manual/configuration.html). Indeed, it lacks additional flexibility offered by file-based configs but enables much easier setup for new applications.

### Injecting loggers into code

It's preferable to inject log instances explicitly through constructors, either using a DI container or simply passing them manually. [Static log provider](https://vostok.gitbook.io/logging/how-to-guides/using-static-log-provider) may be sufficient for simple applications, though.

### Configuring individual loggers

Individual log instances (such as [console log](https://vostok.gitbook.io/logging/implementations/console-log) or [file log](https://vostok.gitbook.io/logging/implementations/file-log)) are typically configured in code by passing a settings object. However, some implementations (namely [file log](https://vostok.gitbook.io/logging/implementations/file-log)) also accept an arbitrary settings provider delegate that can be used to configure from external sources using [Vostok.Configuration](https://vostok.gitbook.io/configuration/) library.

Also, simple filtering and enrichment rules can be supplied from [external configuration](https://vostok.gitbook.io/logging/how-to-guides/external-configuration-rules).