woof

# Woof

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A **pure** _(in both senses of the word!)_ **Scala 3** logging library with **no runtime reflection**.

![logo](dog-svgrepo-com.svg)

# Table of Contents
  - [Highlights](#highlights)
    - [Cross platform](#cross-platform)
  - [Installation](#installation)
  - [Example](#example)
  - [Can I use `SLF4J`?](#can-i-use-slf4j)
    - [Limitations of SLF4J bindings](#limitations-of-slf4j-bindings)
  - [Can I use `http4s`?](#can-i-use-http4s)
  - [Structured Logging](#structured-logging)

## Highlights

* Pure **Scala 3** library
* Made with _Cats Effect_
* Macro based (_no runtime reflection_)
* Configured with plain Scala code

### Cross platform

| Module  | JVM   | scala.js  | native |
|---------|-------|-----------|--------|
| core    | ✅    | ✅        | ✅     |
| http4s  | ✅    | ✅        | ✅     |
| slf4j   | ✅    | 🚫        | 🚫     |
| slf4j-2 | ✅    | 🚫        | 🚫     |

## Installation

> build.sbt

```scala
libraryDependencies ++= Seq(
  "org.legogroup" %% "woof-core"    % "$VERSION",
  "org.legogroup" %% "woof-slf4j"   % "$VERSION", // only if you need to use Woof via slf4j 1.x.x
  "org.legogroup" %% "woof-slf4j-2" % "$VERSION", // only if you need to use Woof via slf4j 2.x.x
  "org.legogroup" %% "woof-http4s"  % "$VERSION", // only if you need to add correlation IDs in http4s 
)
```

You can see a bunch of self-contained examples in the [examples](modules/examples) sub-project. To run them, open `sbt` and run the command `examples/run`:

```
sbt:root> examples/run

Multiple main classes detected. Select one to run:
 [1] examples.AtLeastLevel
 [2] examples.CustomPrinter
 [3] examples.CustomTheme
 [4] examples.ExactLevel
 [5] examples.FileOutput
 [6] examples.HelloWorld
 [7] examples.LogLevelFromEnv
 [8] examples.RegexFilter
 [9] examples.TaglessFinal

Enter number:
```

it will ask you for a number corresponding to the example you wish to run. For a self-contained `Scala.Js` example, look at [modules/examples-scalajs/src/main/scala/examples/HelloScalaJs.scala](modules/examples-scalajs/src/main/scala/examples/HelloScalaJs.scala)

## Example 

```scala
import cats.effect.IO
import org.legogroup.woof.{given, *}

val consoleOutput: Output[IO] = new Output[IO]:
  def output(str: String)      = IO.delay(println(str))
  def outputError(str: String) = output(str) // MDOC ignores stderr

given Filter = Filter.everything
given Printer = NoColorPrinter()

def program(using Logger[IO]): IO[Unit] = 
  for
    _ <- Logger[IO].debug("This is some debug")
    _ <- Logger[IO].info("HEY!")
    _ <- Logger[IO].warn("I'm warning you")
    _ <- Logger[IO].error("I give up")
  yield ()

val main: IO[Unit] = 
  for
    given Log