Add support for grok patterns

[iilyak]

Alfred is a great tool. Thank you for developing it.

This is not an issue but a feature request
It would be really nice to add automatic parsing of an output of a job and store the parsed groups in the variables.
The idea is inspired by filebit

With this feature it would be possible to specify something like (using logstash grok):

node.ps:
  summary: Return list of processes on remote node
  register: node.ps
  command: |
    ssh {{ index .Args 0 }} ps -elf
  ok: node.ps.ok
  fail: node.ps.fail
  grok:
    ssh_error: "ssh: (?<ERROR>[^\,]*)"
    process: "%{F} %{S} %{UID}        %{PID}  %{PPID}  %{C} %{PRI}  %{NI} %{ADDR} %{SZ} %{WCHAN  STIME} %{TTY}          %{TIME} %{CMD}"

node.ps.ok:
  register: node.ps.ok
  command:
    echo '{{ index .Vars "node.ps[*][CMD]" }}'  ### <<--- NOT sure about exact syntax here
  private: true

node.ps.fail:
   
   tasks: node.ping

There are plenty logstash grok patterns here
https://github.com/logstash-plugins/logstash-patterns-core/blob/master/patterns/

There are few grok engines written in go already.

[kcmerrill]

The idea being, grok would look for specific file patters and pass/fail depending if it found it or not?

[khia]

The idea would be to match the output of the command (stdout) against grok pattern. Extract named groups and bind them to the variables, so the parsed results would be available for ok/fail commands.