Hi Roger,

Thanks for the feedback.

Runtime.exec doesn't take arg[0] as a separate parameter, so it may make sense to not split it up in the event. For example, if plan is to execute "hg clone url", but the user forgets to add "hg", then it will look as if "clone" is the command, which could be confusing.

I will change the field name to 'command' to make it consistent with the single arg form of Runtime.exec.

Regarding delimiters, I think there are two use cases. Making something easy for humans to read and making it unambiguous for machine parsing. Since comma, or comma space, might be part of an argument, it is still unsafe for a parser. It would be possible to add escape sequences, but then it would be even harder for humans to read, which I think is the main use case. If we in the future would add support for serializing a String[], we could add another field, i.e. commandArray, which would work for machines without special parse logic.

There is no ProcessEnd event today, but that is something that could be added in the future. The exit status could be useful.

Updated webrev:
http://cr.openjdk.java.net/~egahlin/8222000/

Thanks
Erik

On 2020-03-05 15:27, Roger Riggs wrote:
Hi Erik,

Would the event be more useful if the executable arg[0] was a separate field from the arguments?
Though I exect it depends on what is later evaluating the event fields.

If all of cmdarrray is being joined, then the event field name is more appropriately called 'command';  similar to the single arg form of Runtime.exec and new ProcessBuilder(...).

A small point but the joining with ' ' space has the usual problem of trying to parse out the arguments later.
using ',' comma might be less ambiguous.  (and Arrays.toString).

Otherwise, looks fine to me.

Is there already a Process exited event? Its not quite as convenient to instrument but useful if it captures the exit status. (ProcessImpl - Windows and Linux versions).

Roger



On 3/5/20 9:10 AM, Erik Gahlin wrote:
Hi

Could I have review of a JFR event that is emitted when a process is started from Java.

Bug:
https://bugs.openjdk.java.net/browse/JDK-8222000

Webrev:
http://cr.openjdk.java.net/~egahlin/8222000/

Testing:
tier1,tier2 + jdk/jdk/jfr

Thanks
Erik





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