Logback VS SLF4J

Logback we will use mostly with Ktor, this dependency is not required, but it is nice to see logs of requests + it will get rid of some annoying warnings while running the project

Java -> Logback, Log4j2, JDK (Java Util Logging), Slf4j, e.t.c.

This is a GitHub link to my demo app. It’s simple Spring Boot web app used to debugging various stuff. There are many ways to configure JSON logging in Spring Boot. I decided to use Logback because it is easy to configure and one of the most widely used logging library in the Java Community. To enable JSON logging we need to add below dependencies.

Logback(https://logback.qos.ch/) is another non-commercial Java logging framework. It labels itself as a successor to the previously discussed Log4j framework.

> Then apache decides to put new people on log4j, do a backward incompatible v2 design that nevertheless is worse than slf4j. Why?

slf4j itself isn't a logging framework. It's a facade to logging frameworks.

Simple Logging Facade for Java ( https://www.slf4j.org )

It needs a logging framework behind it - log4j, log4j2, logback, commons, JUL.

The question is "why do log4j2?"

Logback went from the log4j1.x path ( https://logback.qos.ch )

Log4j2 has a lot of features that weren't present when the project started ( https://en.wikipedia.org/wiki/Log4j#Apache_Log4j_2 ).

There is a licensing difference between Logback (LGPL) and Log4jx (Apache Commons).

Also, I'd like you to pay attention to the log consumer. You see, when the E2E scenario fails, it's not always obvious why. Sometimes to understand the source of the problem you have to dig into containers' logs. Thankfully the log consumer allows us to forward a container's logs to any SLF4J logger instance. In this project, containers' logs are forwarded to regular text files (you can find the Logback configuration in the repository). Though it's much better to transfer logs to external logging facility (e.g. Kibana).

This shows that the MariaDB JDBC driver uses Logback as a logging framework. Although Logback is not affected by Log4Shell, it has a related vulnerability (of much lesser severity, no need to panic) fixed in version 1.2.8 and 1.3.0-alpha11. I checked the version used by the connector and found that it used 1.3.0-alpha10. Even though Logback is included as a test dependency in the MariaDB driver, I sent a pull request on GitHub to update it. I encourage you to do the same in any open-source project you find and that includes a vulnerable dependency.

SLF4J with Logback

A few years ago, my team moved from Java to Go. Working on Go projects, we encountered a wide variety of logging frameworks with different APIs, configuration, and formatting. We soon found ourselves longing for a logging abstraction layer like Java’s slf4j, which had proven invaluable for use in reusable libraries or configuring and debugging production systems. So, not long after moving to Go, we began working toward replacing what we had lost in slf4j.

I'm not familiar with Serilog as I code mostly in Java, use slf4j (logs to stdout) and our apps send logs to Cloudwatch using the task definition's awslogs configuration. I prefer it this way because I can customize the log configurations in my task definitions. Also the default stream name has this format prefix-name/container-name/ecs-task-id so I can easily identify the logs of the task I want to look at. I haven't experienced any downsides with this approach and our apps publish a shit ton of logs. Cloudwatch approach looks like you can customize the stream name?

slf4j is open source. You can look at the code.

Java -> Logback, Log4j2, JDK (Java Util Logging), Slf4j, e.t.c.

slf4j para padronização dos logs;

SLF4J

> My God. Logging in protobuf?

Yes, or any other data format and/or transport protocol.

I'm surprised this is up for debate.

> Logging is the lowest of all debugging utilities - its the first thing you ever do writing software - “hello world”. And, while I admire structural logging, the truth is printing strings remains (truly) the lowest common denominator across software developers.

This sort of comment is terribly miopic. You can have a logging API, and then configure your logging to transport the events anywhere, any way. This is a terribly basic feature and requirement, and one that comes out of the box with some systems. Check how SLF4J[1] is pervasive in Java, and how any SLF4J implementation offers logging to stdout or a local file as a very specific and basic usecase.

It turns out that nowadays most developers write software that runs on many computers that aren't stashed over or under their desks, and thus they need efficient and convenient ways to check what's happening either in a node or in all deployments.

[1] https://www.slf4j.org/