Java spark framework enable logging

Question

I'm building a java application with Spark framework with embedded Jetty and handlebars template engine. But when i get an 500 Internal Error, the console didn't say anything. I have added to my pom.xml the dependencies here: http://sparkjava.com/documentation.html#add-a-logger but does not print all exceptions / errors (like errors 500)

Here my pom.xml dependecies

<dependencies>

    <!-- FRAMEWORK:     Spark -->
    <dependency>
        <groupId>com.sparkjava</groupId>
        <artifactId>spark-core</artifactId>
        <version>2.5</version>
    </dependency>

    <!-- TEMPLATES:     Handlebars -->
    <dependency>
        <groupId>com.sparkjava</groupId>
        <artifactId>spark-template-handlebars</artifactId>
        <version>2.3</version>
    </dependency>

    <!-- DB-MAPPING:    sql2o -->
    <dependency>
        <groupId>org.sql2o</groupId>
        <artifactId>sql2o</artifactId>
        <version>1.5.4</version>
    </dependency>

    <!-- DRIVERS: sqlite-->
    <dependency>
        <groupId>org.xerial</groupId>
        <artifactId>sqlite-jdbc</artifactId>
        <version>3.8.11.2</version>
    </dependency>

    <!-- LOGGER:        slf4j -->
    <dependency>
        <groupId>org.slf4j</groupId>
        <artifactId>slf4j-simple</artifactId>
        <version>1.7.21</version>
    </dependency>

</dependencies>

How i can enable all the logging for spark?

Enteritis

you can configure log4j for capturings logs normally – Ballistic

Answer 1

Use log4j to make a logging implementation. That's why you don't have an idea why are you getting an internal server error

http://logging.apache.org/log4j/2.x/

Sublease

Answer 2

To enable logging, just add the following dependency to your project:

<dependency>
  <groupId>org.slf4j</groupId>
  <artifactId>slf4j-simple</artifactId>
  <version>1.7.21</version>
</dependency>

and you can register a catch-all Spark exception handler to log uncaught exceptions:

Spark.exception(Exception.class, (exception, request, response) -> {
    exception.printStackTrace();
});

Elkeelkhound

Answer 3

Not sure if this meant disabling spark or Hadoop in built logging but if thats the case, setting the log level in SparkContext helped me.

sc.setLogLevel("ERROR");

Possible options are ALL, DEBUG, ERROR, FATAL, INFO, OFF, TRACE, WARN

https://spark.apache.org/docs/2.2.0/api/java/org/apache/spark/SparkContext.html#setLogLevel-java.lang.String-

Ellipsoid

Answer 4

Have you added a log4j properties file? Have a look at this documentation.

Configuring Logging Spark uses log4j for logging. You can configure it by adding a log4j.properties file in the conf directory. One way to start is to copy the existing log4j.properties.template located there.

Cowen

I'm using the 2.5 version, and on the website it say to add slf4j: sparkjava.com/documentation.html#add-a-logger – Enteritis

The documentation you're referring to is for Spark the data processing framework, not Spark the web framework. Yes, it's an annoying namespace conflict. ;) – Selfpropulsion

This does not seem to answer the question. This is for Spark Java and not Apache spark :) sparkjava.com/documentation.html#how-do-i-enable-logging – Lheureux