Log Format
There are a few things that dropwizard considered when applying to log.
- It should be human-readable.
- It should be machine parsable.
- Use tall and grep commands to figure out the things that are pear-shaped for sleepy ops.
JSON Log Format
If you want to log in a JSON format for a specific purpose, you can achieve this by adding a module in the project to support JSON format.
In the configuration file.
<dependency>
<groupId>io.dropwizard</groupId>
<artifactId>dropwizard-json-logging</artifactId>
<version>${dropwizard.version}</version>
</dependency>
Types of Logging
Asynchronous Logging
Asynchronous logging is the default logging method in dropwizard. Asynchronous logging helps to maintain low latency by dropping some levels during the logging process whenever it encounters a slow logger coupled with high loading.
How to configure this logging behavior.
- To apply no event dropping, make the discardingThreshold to 0.
- Set neverBlock to true at the other end to ensure that even WARN and ERROR levels are deleted from logging when there is a lot of traffic.
Console Logging
We can also implement console logging in the dropwizard logging system by changing the YAML configuration file. By default, in YAML, file logging is INFO level and target STDOUT,
logging:
appenders:
- type: console
threshold: WARN
target: stderr
File Logging
We can also implement file logging in dropwizard and log to an automatic file set. This method is recommended when you are working in any production environment.
logging:
appenders:
- type: file
# logging file.
currentLogFilename: ./logs/samplefile.log
#file pattern of the log file to store
archivedLogFilenamePattern: ./logs/samplefile-%d.log.gz
#couting archived files to keep.
archivedFileCount: 3
timeZone: UTC
Syslog Logging
We can also log information in dropwizard using the Syslog logging system. Let's see how we can achieve Syslog logging.
logging:
appenders:
- type: syslog
# declare the hostname so the statement will be sent to that system.
host: localhost
#facility to store statements.
facility: local0
Logging Configuration Using HTTP
We can also configure Logging files in dropwizard via HTTP request using LogConfiguratinTask. The duration parameter in the request must be in ISO 8601 format.
Example:
# Configure com.sample.codingninja to WARN
curl -X POST -d "logger=com.sample.codingninja&level=WARN" http://localhost:5000/task/log-level
Frequently Asked Questions
What logging framework is used by dropwizard?
Logback is the logging framework used by the dropwizard.
Does dropwizard also use Log4j?
No dropwizard uses Logback, which is the upgraded version of Log4j.
Can you use more the one level of logging in dropwizard?
Yes, we can apply more than on appenders in dropwizard.
What is the default logging in dropwizard?
Asynchronous logging is the default logging in dropwizard.
Can we filter out a request in logging?
Yes, we can also filter out requests in a log file.
Conclusion
In this blog, we discussed the logging system in dropwizard. We have also learned about the different types of logging methods we can implement in dropwizard, like console log, Syslog, and many more. This blog also discussed the log format, which can be applied in the drop wizard.
To learn more about dropwizard, check out the following articles.
To learn more about DSA, competitive coding, and many more knowledgeable topics, please look into the guided paths on Coding Ninjas Studio. Also, you can enroll in our courses and check out the mock test and problems available to you. Please check out our interview experiences and interview bundle for placement preparations.
Happy Learning!
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