Retrieve more info about jobs when using 'at' adaptor #684
Description
Currently the at adaptor returns very little info once a job has finished. Even getting the correct state or exit code is hard (see #683).
We could get a bit more information about the job by using an external tool such as '/bin/time like so:
/bin/time -v xenon filesystem file list /home/jason > out
Command being timed: "xenon filesystem file list /home/jason"
User time (seconds): 1.15
System time (seconds): 0.05
Percent of CPU this job got: 259%
Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.46
Average shared text size (kbytes): 0
Average unshared data size (kbytes): 0
Average stack size (kbytes): 0
Average total size (kbytes): 0
Maximum resident set size (kbytes): 87552
Average resident set size (kbytes): 0
Major (requiring I/O) page faults: 0
Minor (reclaiming a frame) page faults: 18320
Voluntary context switches: 1334
Involuntary context switches: 233
Swaps: 0
File system inputs: 0
File system outputs: 80
Socket messages sent: 0
Socket messages received: 0
Signals delivered: 0
Page size (bytes): 4096
Exit status: 0
Time provides information on resource usage, as well as the exit code, but only once the application has finished. We could use this to write a /tmp/xenon.at.finished.#ID file which the at adaptor can use to get information about finished jobs.