jloglevel
is a command line tool for changing the logging level in JVM apps in runtime via Jolokia.
JVM has a technology Java Management Extensions (JMX) that allows to monitor and manage JVM applications in runtime. This is done via components called MBeans (managed beans). MBeans have attributes that can be read and operations (methods) that can be executed with JMX.
JVM logging libraries expose MBeans which apart from other features allow control of the logging level in runtime. That means that we can change the logging level of loggers inside the application without restart or modification of files.
JMX has a drawback: it doesn't go well with firewalls, especially in dynamic cloud environments. To overcome this issues, JMX-HTTP bridges exist, and Jolokia is probably the most popular of them. It exposes JMX MBeans over HTTP and allows us to read attributes and call methods using simple GETs and POSTs.
Combining all this together, jloglevel makes it easy to get and set the logging level on a number of JVM applications (e.g. a scaled-out service).
Currently, only Logback library is supported.
$ pip3 install jloglevel
-
Jolokia agent needs to be attached to a JVM (or JVMs) you are going to work with. Follow the Jolokia documentation for the details.
-
Logback must be configured to expose its control via JMX. Technically only
<jmxConfigurator />
needs tp be added tologback.xml
. See JMX Configurator page in the documentation for the details.
There are two common options in every command:
-h
or --host
to specify the IP address and the port where Jolokia agent is listening for incoming connections. Can be multiple. Example: -h 192.168.2.1:8778 -h 192.168.2.2:8778 -h 192.168.2.3:8778
--socks5
for specifying the SOCKS5 proxy IP address and port (if needed). Example: --socks5 127.0.0.1:9999
This might be useful with SSH.
To list the loggers use list-loggers
command:
$ jloglevel list-loggers -h 192.168.2.1:8778
http://192.168.2.1:8778/
ROOT
me
me.ivanyu
me.ivanyu.agenthost
me.ivanyu.agenthost.App
To get the logging levels use get
command:
$ jloglevel get -h 192.168.2.1:8778 -h 192.168.2.2:8778 -h 192.168.2.3:8778
Logger ROOT
http://192.168.2.1:8778/ DEBUG
http://192.168.2.2:8778/ DEBUG
http://192.168.2.3:8778/ DEBUG
By default, the logger is ROOT
. You can get the logging level of another logger using -l/--logger
option:
$ jloglevel get -h 192.168.2.1:8778 -l me.ivanyu.testapp.App
Logger me.ivanyu.testapp.App
http://192.168.2.1:8778/ DEBUG
To set the logging levels use set
command:
$ jloglevel set -h 192.168.2.1:8778 -h 192.168.2.2:8778 -h 192.168.2.3:8778 TRACE
Logger ROOT
http://192.168.2.1:8778/ OK
http://192.168.2.2:8778/ OK
http://192.168.2.3:8778/ OK
Starting from this moment, the logging level of the ROOT logger is TRACE
.
As with get
command, you can specify a logger different from the default ROOT
using -l/--logger
option:
$ jloglevel set -h 192.168.2.1:8778 -l me.ivanyu.testapp.App TRACE
Logger me.ivanyu.testapp.App
http://192.168.2.1:8778/ OK
The project is started and maintained by Ivan Yurchenko ([email protected]).
Contributions are welcome!
Copyright 2017 Ivan Yurchenko
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.