Table of Contents
# options
options online tutorialopen in new window
TIP
Global options
| Name | Default Value | Description |
|---|---|---|
| unsafe | false | whether to enhance to system-level class. Use it with caution since JVM may hang |
| dump | false | whether to dump enhanced class to the external files. If it's on, enhanced class will be dumped into /${application dir}/arthas-class-dump/, the specific output path will be output in the console |
| batch-re-transform | true | whether to re-transform matched classes in batch |
| json-format | false | whether to output in JSON format |
| disable-sub-class | false | whether to enable matching child classes. The default value is true. If exact match is desire, turn off this flag |
| support-default-method | true | whether to enable matching default method in interface. The default value is true. Refer to #1105open in new window |
| save-result | false | whether to save execution result. All execution results will be saved to ~/logs/arthas-cache/result.log when it's turned on |
| job-timeout | 1d | default timeout for background jobs. Background job will be terminated once it's timed out (i.e. 1d, 2h, 3m, 25s) |
| print-parent-fields | true | This option enables print files in parent class, default value true. |
| verbose | false | This option enables print verbose information |
| strict | true | whether to enable strict mode |
# View all options
$ options
LEVEL TYPE NAME VALUE SUMMARY DESCRIPTION
-------------------------------------------------------------------------------------------------------
0 boolea unsafe false Option to support sy This option enables to proxy functionality
n stem-level class of JVM classes. Due to serious security r
isk a JVM crash is possibly be introduced.
Do not activate it unless you are able to
manage.
1 boolea dump false Option to dump the e This option enables the enhanced classes t
n nhanced classes o be dumped to external file for further d
e-compilation and analysis.
1 boolea batch-re-tra true Option to support ba This options enables to reTransform classe
n nsform tch reTransform Clas s with batch mode.
s
2 boolea json-format false Option to support JS This option enables to format object outpu
n ON format of object t with JSON when -x option selected.
output
1 boolea disable-sub- false Option to control in This option disable to include sub class w
n class clude sub class when hen matching class.
class matching
1 boolea support-defa true Option to control in This option disable to include default met
n ult-method clude default method hod in interface when matching class.
in interface when c
lass matching
1 boolea save-result false Option to print comm This option enables to save each command's
n and's result to log result to log file, which path is ${user.
file home}/logs/arthas-cache/result.log.
2 String job-timeout 1d Option to job timeou This option setting job timeout,The unit c
t an be d, h, m, s for day, hour, minute, se
cond. 1d is one day in default
1 boolea print-parent true Option to print all This option enables print files in parent
n -fields fileds in parent cla class, default value true.
ss
1 boolea verbose false Option to print verb This option enables print verbose informat
n ose information ion, default value false.
1 boolea strict true Option to strict mod By default, strict mode is true, not allow
n e ed to set object properties. Want to set o
bject properties, execute `options strict
false`
# Get special option value
$ options json-format
LEVEL TYPE NAME VALUE SUMMARY DESCRIPTION
--------------------------------------------------------------------------------------------
2 bool json-format false Option to support This option enables to format object
ean JSON format of obj output with JSON when -x option selec
ect output ted.
TIP
By default, json-format is false. When set json-format to true, commands like wathc/tt will print result with json format.
# Set special option value
For example, to enable saving command execution result, input the command below:
$ options save-result true
NAME BEFORE-VALUE AFTER-VALUE
----------------------------------------
save-result false true
# Set unsafe to true to enhance the classes under the java.* package
By default, watch/trace/tt/trace/monitor command do not support classes under java.* package. You can set unsafe to true to enhance the classes under the java.* package.
$ options unsafe true
NAME BEFORE-VALUE AFTER-VALUE
-----------------------------------
unsafe false true
$ watch java.lang.invoke.Invokers callSiteForm
Press Q or Ctrl+C to abort.
Affect(class count: 1 , method count: 1) cost in 61 ms, listenerId: 1
# Turn off strict mode, allow setting object properties in ognl expressions
TIP
since 3.6.0
For new users, there may be misuses when writing ognl expressions.
For example, for Student, when judging the age is equal to 18, the conditional expression may be mistakenly written as target.age=18, which actually sets the age of the current object to 18. The correct spelling is target.age==18.
In order to prevent misuse like the above, Arthas enables strict mode by default, in ognl expressions, it is forbidden to update the property of the object or call the setter method.
Take MathGame as an example, the following error message will appear.
$ watch demo.MathGame primeFactors 'target' 'target.illegalArgumentCount=1'
Press Q or Ctrl+C to abort.
Affect(class count: 1 , method count: 1) cost in 206 ms, listenerId: 1
watch failed, condition is: target.illegalArgumentCount=1, express is: target, By default, strict mode is true, not allowed to set object properties. Want to set object properties, execute `options strict false`, visit /Users/admin/logs/arthas/arthas.log for more details.
If the user want to change the object properties in the ognl expression, you can execute options strict false to turn off the strict mode.
- For more information, please refer to: https://github.com/alibaba/arthas/issues/2128