.slate.js

S.on('appActivated', function (event, app) {
    S.log('appActivated:' + app.name());
});

fluentd.conf

<source>
  type forward
  port 24224
</source>

<match keylogger>
    type copy
    <store>
        type datacounter
        #unit minute
        count_interval 1m
        count_key app
        tag keycounter
        aggregate all
        # patternX: X(1-9)
        pattern1 Terminal     ^Terminal$
        pattern2 MacVim       ^MacVim$
        pattern3 LimeChat     ^LimeChat$
        pattern4 Slack        ^Slack$
        pattern5 GoogleChrome ^Google\s*Chrome$
    </store>
    <store>
        type stdout
    </store>
</match>


<match keycounter>
    type copy
    <store>
        type      growthforecast
        gfapi_url http://localhost:5127/api/
        service   key
        section   count
        tag_for   ignore
        name_keys Terminal_count,MacVim_count,LimeChat_count,Slack_count,GoogleChrome_count
    </store>
    <store>
        type         mackerel
        service      songmu
        api_key      xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
        metrics_name keylogger.${out_key}
        out_keys     Terminal_count,MacVim_count,LimeChat_count,Slack_count,GoogleChrome_count
    </store>
    <store>
        type stdout
    </store>
</match>

<match **>
  type stdout
</match>

keylogger.pl

#!/usr/bin/env perl
use 5.014;
use warnings;
#use utf8;
use autodie;
$| = 1;

my $current_app = 'Terminal';
while (my $line = <>) {
    if (my ($app) = $line =~ /Slate\[.*appActivated:(.*)/) {
        if ($app =~ /ターミナル/) {
            $app = 'Terminal';
        }
        else {
            $app =~ s/[^a-zA-Z0-9 ]//g;
        }
        $current_app = $app; next;
    }
    my $press_key = quotemeta 'org.pqrs.Karabiner --Debug-- KeyboardEventCallback [ caught]: eventType 10';
    if ($line =~ /$press_key/) {
        printf qq[{"app": "%s"}\n], $current_app if $current_app;
    }
}

1;

keylogger.sh

#!/bin/sh
tail -F /var/log/system.log | perl $HOME/service/keylogger/keylogger.pl | fluent-cat keylogger