xargsd 0.1.3

xargs-like daemon accepting input from arbitrary processes

Like xargs, but accepts arguments from arbitrary processes, and executes eagerly as long as there are arguments available.

That is to say, xargsd [...] -- foobar, when it receives arguments a and b, will execute foobar a b. If arguments c through f arrive while foobar a b is executing, then foobar c d e f will get run as soon as the first invocation finishes.

Examples

• A toy example, demonstrating the very basic functionality:

  $ python -m xargsd --socket-file temp.sock -vvv -- echo &
  [1] 14917
  $ submit() { python -m xargsd.client --socket-file temp.sock -- "$@"; }
  $ submit a
  INFO:root:executing ['echo', 'a']
  a
  $ submit b c d
  INFO:root:executing ['echo', 'b', 'c', 'd']
  b c d
  

  (Note that the INFO: lines and the following ones are printed by xargsd, not the client.)

• A slightly-less-toy example, which demonstrates how commands are batched up while a previous command is executing:

  $ echo 'date; sleep "$@"' > date-and-sleep.sh
  $ python -m xargsd --socket-file temp.sock -vvv -- bash date-and-sleep.sh &
  [4] 15714
  $ submit() { echo "submitting $@"; python -m xargsd.client --socket-file temp.sock -- "$@"; }
  $ submit 1; sleep 0.1; submit 0.99; sleep 0.1; submit 1.01; sleep 3
  submitting 1
  INFO:root:executing ['bash', 'date-and-sleep.sh', '1']
  Sun May 12 09:53:13 PDT 2019
  submitting 0.99
  submitting 1.01
  DEBUG:root:finished executing ['bash', 'date-and-sleep.sh', '1']: status 0
  INFO:root:executing ['bash', 'date-and-sleep.sh', '0.99', '1.01']
  Sun May 12 09:53:14 PDT 2019
  DEBUG:root:finished executing ['bash', 'date-and-sleep.sh', '0.99', '1.01']: status 0
  

• A completely serious example, using watchman to run xargsd.client whenever a file (whose name matches some pattern) changes:

  $ watchman watch .
  $ watchman -- trigger . pytest -p '.*\.py$' -X -p '(^|.*/)\.' -- bash -c 'python -m xargsd.client --socket-file .xargsd-pytest.sock -- .'
  $ python -m xargsd --unique --socket-file .xargsd-pytest.sock -vvv -- pytest --color=yes
  

  Then save a .py file and watch the daemon execute pytest .