Correlate your services logging with Spring Boot

In a modern service landscape, especially when using containers, you are probably using something like the ELK stack (Elasticsearch, Logstash, Kibana) to flow all the logging into.
But how to find from all those loglines what caused the nasty bug after a innocent buttonpress?
One of the easy answers to this is what’s called a correlation id – basically a unique number assigned to that buttonpress which gets carried around between the services and added to every logline.
Sounds good you say? it is so let’s see how to do this.
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Show Logback Configuration Status with Groovy Configuration

Logback is a SLF4J API implementation for logging messages in Java and Groovy. We can configure Logback with a Groovy configuration file. The file is a Groovy script and allows for a nice an clean way (no XML) to configure Logback. If we want to show the logging configuration and see how Logback is configured we must add a StatusListener implementation in our configuration. The StatusListener implementation prints out the configuration when our application starts. Logback provides a StatusListener for outputting the information to system out or system error streams (OnConsoleStatusListener and OnErrorConsoleStatusListener). If we want to disable any status messages we use the NopStatusListener class.

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Redirect Logging Output to Standard Error with Logback

When we use Logback as SLF4J API implementation in our code we can have our logging output send to our console. By default the standard output is used to display the logging output. We can alter the configuration and have the logging output for the console send to standard error. This can be useful when we use a framework that uses the standard output for communication and we still want to see logging from our application on the console. We set the property target for the ConsoleAppender to the value System.err instead of the default System.out.

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JavaScript: console logging (with IE safety)

Every once in a while I work on a site which has some or copious amounts of javascript. Now I do not mind this at all. But it’s pretty tedious stuff writing the code and putting in loggers. And when you’re working on something and you have to test it on IE. Well let’s just say the console may cause some problems.

But rather then removing all the logging i’ve found there’s an easy solution. Building yourself a logger like structure which checks the existence of the console before writing. That way you can add logging statements without crashing the entire application. Continue reading