...
    def _handle_pubmsg(self, connection, event):
        trigger = 'irc.pubmsg'
        payload = {
            'source': {
                'nick': event.source.nick,
                'host': event.source.host
            },
            'channel': event.target,
            'timestamp': event.timestamp,
            'message': event.arguments[0]
        }
        self._sensor_service.dispatch(trigger=trigger, payload=payload)
...

{
    "source": {
        "nick": "Kami__",
        "host": "gateway/web/irccloud.com/x-uvv"
    },
    "channel": "#test989",
    "timestamp": 1419166748,
    "message": "this is a test message"
}

import httplib
import requests
from st2actions.runners.pythonrunner import Action

SEND_EMAIL_API_URL = 'https://api.mailgun.net/v2/%(domain)s/messages'

class SendEmailAction(Action):
    def run(self, sender, recipient, subject, text, html=None):
        domain = self.config['domain']
        api_key = self.config['api_key']

        data = {
            'from': sender,
            'to': recipient,
            'subject': subject,
            'text': text
        }

        if html:
            data['html'] = html

        api_url = SEND_EMAIL_API_URL % {'domain': domain}
        response = requests.post(api_url, auth=('api', api_key), data=data)
        return response.status_code == httplib.OK

---
  name: "relayed_matched_irc_message"
  description: "Relay IRC message to Slack if the message contains word StackStorm"
  enabled: true

  trigger:
    type: "irc.pubmsg"
    parameters: {}

  criteria:
      trigger.message:
          type: "icontains"
          pattern: "StackStorm"

  action:
    ref: "slack.post_message"
    parameters:
        message: "{{trigger.source.nick}} on {{trigger.channel}}: {{trigger.message}}"
        channel: "#irc-relay"