https://github.com/hseeberger/log4scala
Scala 3 sugar for logging
https://github.com/hseeberger/log4scala
logging scala
Last synced: 6 months ago
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Scala 3 sugar for logging
- Host: GitHub
- URL: https://github.com/hseeberger/log4scala
- Owner: hseeberger
- License: apache-2.0
- Archived: true
- Created: 2020-12-20T20:16:19.000Z (over 5 years ago)
- Default Branch: main
- Last Pushed: 2020-12-23T11:29:13.000Z (over 5 years ago)
- Last Synced: 2025-11-19T22:22:20.976Z (7 months ago)
- Topics: logging, scala
- Language: Scala
- Homepage:
- Size: 28.3 KB
- Stars: 1
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# log4scala #
log4scala is a library providing convenient and performant logging for Scala 3. It piggybacks on
[Apache Logj4 2](https://logging.apache.org/log4j/2.x) (but you could use other backends like
[Logback](http://logback.qos.ch/)) and it automagically applies the check-enabled-idiom thanks to
Scala 3 metaprogramming.
In a nutshell, you can invoke logging methods like `info` without checking if the respective log
level is enabled, because that is handled for you by the compiler:
``` scala
def expensive() = ??? // Very expensive construction of "expensive"
val logger = Logger(getClass)
logger.info(s"I am an $expensive log message ;-)")
```
The compiler will – more or less – create the following code for you:
``` scala
...
// maybeCreateMessage() would return something like "I am an $expensive log message ;-)"
if (logger.isInfoEnabled) logger.info(maybeCreateMessage())
```
So if the respective log level is not enabled, the potentially expensive construction of the log
message will not happen, even though you do not have to spend any efforts on that.
Further log4scala makes it easy to work with context maps (a.k.a. MDCs):
``` scala
withContextMap("key1" -> "value1", "key2" -> "value2") {
logger.info("Some message")
...
logger.info("Some other message")
}
```
The `withContextMap` method takes one or more key-value-pairs and a block of code. Within that block
the key-value-pairs are put on the current context and removed afterwards even in the case of an
exception. It also nicely integrates with Log4j Thread Context Maps and SLF4J MDCs.
log4scala is inspired by:
- [Scala Logging](https://github.com/lightbend/scala-logging)
- [Log4j](https://github.com/Log4s/log4s)
- [Scala 3 / Dotty docs](http://dotty.epfl.ch/docs/reference/metaprogramming/inline.html)
## Contribution policy ##
Contributions via GitHub pull requests are gladly accepted from their original author. Along with
any pull requests, please state that the contribution is your original work and that you license
the work to the project under the project's open source license. Whether or not you state this
explicitly, by submitting any copyrighted material via pull request, email, or other means you
agree to license the material under the project's open source license and warrant that you have the
legal authority to do so.
## License ##
This code is open source software licensed under the
[Apache-2.0](http://www.apache.org/licenses/LICENSE-2.0) license.