On Fri, 15 Oct 2021 10:58:29 GMT, Denghui Dong <dd...@openjdk.org> wrote:
>> I proposed to extend DCmd to allow Java developers to customize their own
>> diagnostic commands last week.
>>
>> At present, I have implemented a preliminary version.
>>
>> In the current implementation, I provided some simple APIs in the Java layer
>> (under sun.management.cmd) for defining and registering commands.
>>
>> - Executable interface
>> Java diagnostic commands need to implement this interface, the interface
>> only contains a simple method:
>>
>> /**
>> * @param output the output when this executable is running
>> */
>> void execute(PrintWriter output);
>>
>>
>> - Add two annotations (@Command and @Parameter) to describe the command meta
>> info
>>
>> - Use Factory API to register command, the following forms are supported
>>
>> @Command(name = "My.Echo", description = "Echo description")
>> class Echo implements Executable {
>>
>> @Parameter(name = "text", ordinal=0, isMandatory = true)
>> String text;
>>
>> @Parameter(name = "repeat", isMandatory = true, defaultValue = "1")
>> int repeat;
>>
>> @Override
>> public void execute(PrintWriter out) {
>> for (int i = 0 ; i < repeat; i++) {
>> out.println(text);
>> }
>> }
>> }
>>
>> Factory.register(Echo.class);
>>
>>
>>
>> Factory.register("My.Date", output -> {
>> output.println(new Date());
>> });
>>
>>
>> - When the command is running, the VM will call `Executor.executeCommand` to
>> execute the command. In the implementation of Executor, I introduced a
>> simple timeout mechanism to prevent the command channel from being blocked.
>>
>> At the VM layer, I extended the existing DCmd framework(implemented JavaDCmd
>> and JavaDCmdFactoryImpl) to be compatible with existing functions (jmx,
>> help, etc.).
>>
>> In terms of security, considering that the SecurityManager will be
>> deprecated, there are not too many considerations for the time being.
>>
>> Any input is appreciated.
>>
>> Thanks,
>> Denghui
>
> Denghui Dong has updated the pull request incrementally with one additional
> commit since the last revision:
>
> print argument key if not found
Hi Denghui,
as I wrote before, I am neutral on this. But I agree with @egahlin that this
seems to be more on JEP level. A PR is not the right first step for this, and I
am afraid you won't build much consensus here. Maybe discuss this first on the
serviceability ML? Or on hotspot-dev?
Kind Regards, Thomas
-------------
PR: https://git.openjdk.java.net/jdk/pull/5938
