Sensu with sensu-plugins-slack no sending message - ubuntu-14.04

Question

On my Sensu server (non-enterprise) I first installed the https://github.com/sensu-plugins/sensu-plugins-slack plugin via sudo sensu-install -p slack.
My configuration files located on my sensu server are as following.
/etc/sensu/conf.d/handler_config_slack.json:
{
"handlers": {
"slack": {
"type": "pipe",
"command": "/usr/local/bin/handler-slack.rb",
"severites": ["critical", "unknown"]
}
},
"slack": {
"webhook_url": "https://hooks.slack.com/services/...",
"username": "sensu",
"channel": "#ops",
"timeout": 10
}
}
/etc/sensu/conf.d/client.json:
{
"client": {
"name": "sensu-server-client-test",
"address": "x.x.x.x",
"subscriptions": [
"test"
],
"keepalive": {
"thresholds": {
"warning": 30,
"critical": 40
},
"handlers": ["slack"],
"refresh": 300
}
}
}
And the sensu remote client servers file /etc/sensu/conf.d/client.json:
{
"client": {
"name": "sensu-client-test",
"address": "x.x.x.x",
"subscriptions": [
"test"
],
"keepalive": {
"thresholds": {
"warning": 30,
"critical": 40
},
"handlers": ["slack"],
"refresh": 300
}
}
}
/var/log/sensu/sensu-srver.log:
{"timestamp":"2016-02-21T15:04:59.771989+0000","level":"info","message":"handler output","handler":{"type":"pipe","command":"handler-slack.rb","severites":["critical","unknown"],"name":"slack"},"output":["only handling every 180 occurrences: sensu-server-client-test/disk\n"]}
I get a remote sensu client running and connected and I then deliberately stop the remote client server to produce warning and critical events from the keepalive checks. I would like a message to be sent to my slack channel however nothing is being sent.
What am I doing wrong?

Answer 1

Simple error, changed the following:
"command": "/usr/local/bin/handler-slack.rb",
To the following:
"command": "handler-slack.rb",