Fluentd
Scala
The fluent-logger-scala library is used to post records from Scala applications to Fluentd.
This article explains how to use it.
Prerequisites
- Basic knowledge of Scala and sbt
- Basic knowledge of Fluentd
- Scala 2.11.0 or later
- sbt 0.12.0 or later
Installing Fluentd
Please refer to the following document to install Fluentd:
Modifying the Config File
Configure Fluentd to use the forward input plugin as its data source:
<source>
@type forward
port 24224
</source>
<match fluentd.test.**>
@type stdout
</match>
Restart Fluentd after configuring.
# for fluent-package (rpm/deb)
$ sudo systemctl restart fluentd
Using fluent-logger-scala
Add the following lines to build.sbt:
resolvers += "Apache Maven Central Repository" at "https://repo.maven.apache.org/maven2/"
libraryDependencies += "org.fluentd" %% "fluent-logger-scala" % "(version)"
See release notes for the revision information.
or
resolvers += "Sonatype Repository" at "http://oss.sonatype.org/content/repositories/releases"
libraryDependencies += "org.fluentd" %% "fluent-logger-scala" % "(version)"
Create an app with the following code:
import org.fluentd.logger.scala.FluentLoggerFactory
import scala.collection.mutable.HashMap
object Sample {
val LOG = FluentLoggerFactory.getLogger("fluentd.test")
def main(args: Array[String]): Unit = {
...
val data = new HashMap[String, String]();
data.put("from", "userA");
data.put("to", "userB");
LOG.log("follow", data);
...
}
}
Further information on the API can be found here.
Executing the script will send the logs to Fluentd:
$ sbt
> run
The logs should be output to /var/log/fluent/fluentd.log or the standard output of the Fluentd process via the stdout output plugin.
Production Deployments
Output Plugins
Various output plugins are available for writing records to other destinations:
- Examples
- List of Plugin References
High-Availability Configurations of Fluentd
For high-traffic websites (more than 5 application nodes), we recommend using the high-availability configuration for Fluentd. This will improve the reliability of data transfer and query performance.
Monitoring
Monitoring Fluentd itself is also important. The article below describes the general monitoring methods for Fluentd.