Sensu Go Slack Handler

The Sensu Slack handler is a Sensu Event Handler that sends event data to
a configured Slack channel.

Installation

Download the latest version of the sensu-slack-handler from releases,
or create an executable script from this source.

From the local path of the slack-handler repository:

go build -o /usr/local/bin/sensu-slack-handler main.go

Configuration

Example Sensu Go handler definition:

slack-handler.json

{
    "api_version": "core/v2",
    "type": "Handler",
    "metadata": {
        "namespace": "default",
        "name": "slack"
    },
    "spec": {
        "type": "pipe",
        "command": "sensu-slack-handler --channel '#general' --timeout 20 --username 'sensu' ",
        "env_vars": [
            "SLACK_WEBHOOK_URL=https://www.webhook-url-for-slack.com"
        ],

        "timeout": 30,
        "filters": [
            "is_incident"
        ]
    }
}

sensuctl create -f slack-handler.json

Example Sensu Go check definition:

{
    "api_version": "core/v2",
    "type": "CheckConfig",
    "metadata": {
        "namespace": "default",
        "name": "dummy-app-healthz"
    },
    "spec": {
        "command": "check-http -u http://localhost:8080/healthz",
        "subscriptions":[
            "dummy"
        ],
        "publish": true,
        "interval": 10,
        "handlers": [
            "slack"
        ]
    }
}

Security Note: The Slack webhook url is treated as a security sensitive configuration option in this example and is loaded into the handler config as an env_var instead of as a command argument. Command arguments are commonly readable from the process table by other unprivaledged users on a system (ex: ps and top commands), so it's a better practise to read in sensitive information via environment variables or configuration files on disk. The --webhook-url flag is provided as an override for testing purposes.

Usage examples

Help:

The Sensu Go Slack handler for notifying a channel

Usage:
  sensu-slack-handler [flags]

Flags:
  -c, --channel string       The channel to post messages to (default "#general")
  -h, --help                 help for handler-slack
  -i, --icon-url string      A URL to an image to use as the user avatar (default "http://s3-us-west-2.amazonaws.com/sensuapp.org/sensu.png")
  -t, --timeout int          The amount of seconds to wait before terminating the handler (default 10)
  -u, --username string      The username that messages will be sent as (default "sensu")
  -w, --webhook-url string   The webhook url to send messages to, defaults to value of SLACK_WEBHOOK_URL env variable