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https://github.com/mattroberts297/slf4s
A Simple Logging Facade for Scala
https://github.com/mattroberts297/slf4s
logging macros scala
Last synced: 28 days ago
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A Simple Logging Facade for Scala
- Host: GitHub
- URL: https://github.com/mattroberts297/slf4s
- Owner: mattroberts297
- License: mit
- Created: 2014-02-05T21:19:46.000Z (almost 11 years ago)
- Default Branch: 2.12
- Last Pushed: 2019-06-17T17:35:21.000Z (over 5 years ago)
- Last Synced: 2024-09-27T21:05:22.990Z (about 1 month ago)
- Topics: logging, macros, scala
- Language: Scala
- Homepage: http://slf4s.org/
- Size: 455 KB
- Stars: 15
- Watchers: 3
- Forks: 6
- Open Issues: 4
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
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# About
A Simple Logging Facade for Scala (SLF4S) built on top of SLF4J.
# Features
* Call by macro expansion (call by name in Scala 2.9);
* A Logging mixin for conveniently obtaining a Logger;
* A LoggerFactory that is `ClassTag` aware;
* Built for Scala 2.9, 2.10 and 2.11;
* Tested on Java 6, 7 and 8; and
* Tracks [slf4j](http://www.slf4j.org/) releases.
The use of macros means that calls to `log.debug` are expanded into `if (log.isDebugEnabled) log.debug` at compile time.
# Installation
### Build.scala
```scala
libraryDependencies ++= Seq(
"org.slf4s" %% "slf4s-api" % "1.7.12",
"ch.qos.logback" % "logback-classic" % "1.1.2"
)
```
You don't have to use [logback](http://logback.qos.ch/), any [slf4j](http://www.slf4j.org/) compatible framework will do.
# Usage
### The Logging Trait
The `Logging` trait provides a `protected val log` to your class, so it'll be available in the local scope, but won't pollute your interface. You can also reference it via a self type if you're using the cake pattern.
```scala
package org.slf4s
import org.scalatest.WordSpec
class LoggingExampleSpec extends WordSpec with Logging {
"The Logging trait should be easy to use" in {
val importantValue = 10
log.debug(s"importantValue: $importantValue")
val importantThrowable = new Throwable
log.debug(s"importantValue: $importantValue", importantThrowable)
}
}
```
### The LoggerFactory Object
The `LoggerFactory` gives you great flexibility and behaves much like the [slf4j](http://www.slf4j.org/) LoggerFactory. You probably only need to use this if you wish to log as a class other than the one in scope.
``` scala
package org.slf4s
import org.scalatest.WordSpec
class LoggerFactoryExampleSpec extends WordSpec {
"The LoggerFactory should be familiar" in {
val log = LoggerFactory.getLogger[LoggerFactoryExampleSpec]
val importantValue = 10
log.debug(s"importantValue: $importantValue")
val importantThrowable = new Throwable
log.debug(s"importantValue: $importantValue", importantThrowable)
}
}
```
### String Interpolation
Scala 2.10.0 offers a new mechanism to create strings from your data: [String Interpolation](http://docs.scala-lang.org/overviews/core/string-interpolation.html). This allows you to to embed variable references and expressions directly in processed string literals.
``` scala
package org.slf4s
import org.scalatest.WordSpec
class StringInterpolatorExampleSpec extends WordSpec with Logging {
"String interpolation should work" in {
val name = "James"
val height = 1.9d
log.debug(s"Hello, $name") // Hello, James
log.debug(s"1 + 1 = ${1 + 1}") // 1 + 1 = 2
log.debug(f"$name%s is $height%2.2f meters tall") // James is 1.90 meters tall
log.debug(raw"a\nb") // New line is preserved
}
}
```
### The Underlying Field
The [`Logger`](http://slf4s.org/api/1.7.12/#org.slf4s.Logger) instance exposes an [`underlying`](http://slf4s.org/api/1.7.12/index.html#org.slf4s.Logger@underlying:org.slf4j.Logger) field that enables you to call slf4j methods directly. This is useful if you wish to avoid a macro expansion for some reason.
# Documentation
For those who prefer not to use an IDE, I've made the [ScalaDoc](http://slf4s.org/api/1.7.12/) available online.