Zilog

Structured logging library for ZIO

Using Zilog in your project

Add Zilog to your dependencies

libraryDependencies += "com.github.mvv.zilog" %% "zilog" % "0.1-M14"

If you plan to use custom compound structured arguments (like in the example below), you might want to also add sredded-generic dependency for the deriveStructured macro:

libraryDependencies += "com.github.mvv.sredded" %% "sredded-generic" % "0.1-M2" % Provided

Running the following example program

import com.github.mvv.sredded.StructuredMapping
import com.github.mvv.sredded.generic.deriveStructured
import com.github.mvv.zilog._
import zio.{App, ZEnv, ZIO}

final case class Request(src: String, method: String, path: String)
object Request {
  implicit val structured: StructuredMapping[Request] = deriveStructured
}

object RequestKey extends Logging.Key[Request]("request")
object CorrelationIdKey extends Logging.Key[String]("correlationId")
object CustomerIdKey extends Logging.Key[Long]("customerId")

object LoggingApp extends App {
  implicit val logger: Logger = Logger[LoggingApp.type]
  override def run(args: List[String]): ZIO[ZEnv, Nothing, Int] =
    {
      log.withLogArgs(RequestKey(Request("src", "GET", "/foo")), CorrelationIdKey("someId")) {
        log.info("Logic go brrrrr", CustomerIdKey(123))
      }
    } .provideCustomLayer(Logging.consoleJson()).as(0)
}

should produce something like (as a single line)

{
  "timestamp": "2020-05-01T00:00:00.000Z",
  "fiberId": "#0",
  "logger": "LoggingApp$",
  "level": "INFO",
  "message": "Logic go brrrrr",
  "args": {
    "request": {
      "src": "src",
      "method": "GET",
      "path": "/foo"
    },
    "correlationId": "someId",
    "customerId": 123
  },
  "stackTrace": null,
  "sourceFile": "LoggingApp.scala",
  "sourceClass": "LoggingApp",
  "sourceMethod": "run",
  "sourceLine": 20
}

Submodules

• zilog-sager allows you to access Logging instances in Sager environments
• zilog-over-slf4j provides a Logging service that uses SLF4J as a backend