Simple Java only logger without reflection or other magic
- Logger with lazy messages
- Logger without reflections
- Logger which can run natively (GraalVM)
- Logger which is customizable
- Logger without huge dependency tree
- Logger simple to use (Always hard to find out how to set up SLF4J - afterwards it's awesome)
Config -> Logger (LogLevel) -> Formatter (LogLevel) -> Writer
- Default
import berlin.yuna.justlog.logger.Logger;
public class UsageTest {
private static final Logger logger = Logger.defaultLogger();
public void log() {
logger.warn(() -> "message", () -> new RuntimeException("exception"));
}
}
- Available LogLevel
- Configuration priorities [Environment Variables, Config Files, DSL]
- Configuration folders [classpath:resource, userDir, userDir:config]
- Configuration files [application.properties, logger.properties]
- Configuration values are [case insensitive]
- Every config without
logger.
prefix will be ignored
- Every config without
- Example config
#Default logger config
logger.file=/user/home/service/config/custom.properties
logger.level=INFO
logger.threads=2
logger.writer.encoding=UTF8
logger.SimpleWriter.buffer-size=10
logger.pattern="[%p{l=10}] [%l{l=5}] [%d{p=HH:mm:ss.SSS}] [%c{l=10}] [%T{l=10,i=0}:%M:%L] %m%n%e{p=berlin,yuna}"
#Default logger config - the keyword root is optional and has no meaning
logger.root.file=/user/home/service/config/custom.properties
#Logger specific config
logger.myLoggerName.file=/user/home/service/config/custom.properties
logger.myLoggerClass.level=ERROR
logger.myLoggerClass.myFormatter.pattern="[[%d{p=HH:mm:ss.SSS}] [%c{l=10}] %m%n%e"
- The log pattern defines the format of the log message by using placeholders
- Placeholders are a simple
chars
with%
as prefix - Placeholders are named
provicers
in code - It is also possible to create custom providers, see examples of DefaultProviders
- Placeholders are a simple
- All default Providers:
Char | Accepts | Name | Description |
---|---|---|---|
a | l | IP Address | First IP Address of the current host |
c | l | logger name | logger name |
d | l, z | DateTime | date time using DateTimeFormatter |
e | p | Exception | exception |
h | l | Hostname | Hostname |
l | l | Log Level | log level for that message |
m | - | Message | actual message |
n | - | New Line | new line |
p | l | PID | process id of the current thread |
T | l, i | Caller Class | Caller class name [slows the performance] |
M | l, i | Caller Method | Caller Method [slows the performance] |
L | l, i | Caller Line Number | Caller Line Number [slows the performance] |
- Every Provider accepts
,
separated parameters within brackets{}
like on default:
Char | Name | Examples |
---|---|---|
l | Length | %l{l=5} Loglevel length %c{l=10} LoggerName length |
i | Index | %T{i=0} Caller class index number (0 = default) |
p | Pattern | %d{p=HH:mm:ss.SSS} Date format %e{p=berlin;yuna} include only traces with packages in berlin and yuna |
z | TimeZone | %d{z=UTC} Sets the time zone (UTC = default) |
- DSL Config
public class UsageTest {
private final Logger logger1;
private final Logger logger2;
public UsageTest {
final HashMap<String, String> myOptionalConfig = new HashMap<>();
logger1 = new DefaultLogger("LoggerName")
.config(myOptionalConfig)
.level(LogLevel.TRACE)
.writer(new SimpleWriter())
.formatter(new SimpleLogFormatter())
.formatter().pattern("[%p{l=10}] [%l{l=5}] [%d{p=HH:mm:ss.SSS}] [%c{l=10}] [%T{l=10,i=0}:%M:%L] %m%n%e{p=berlin,yuna}").logger();
logger2 = DefaultLogger.instance().config(myOptionalConfig).level(LogLevel.TRACE);
}
}
- Test the logger in a project
- String format message
- Config to enable automatically Json / Line logging
- FileWriter
- Accept Multiple Writer
- Split into Java version 8,11,17