Slack notify

This tool implements the communication with slack for various purposes. It supports the following 3 modes:

• msg: sends a short message to slack. Useful for notifications from scripts.
• monit: sends a monit event to slack. See below the example of configuration and the message.
• mail: forwards local mail to slack. See below the the example of configuration and the message.

Help screen

NAME:
   slack-notify - send information to slack via webhook

USAGE:
   slack-notify [global options] command [command options] [arguments...]

VERSION:
   2.0.0/2019-03-04T21:38:30+0000/7bfbb0

COMMANDS:
     msg      send a plain message to slack
     monit    monit mode, read information from env variables
     mail     relay user's email to slack
     help, h  Shows a list of commands or help for one command

GLOBAL OPTIONS:
   --webhook value           Slack webhook for sending messages [$SN_WEBHOOK]
   --channel value           Slack channel where to send message (default: "#random") [$SN_CHANNEL]
   --username value          Slack username (default: "slack-notify@<hostname>") [$SN_USERNAME]
   --config value, -f value  Read configuration from file. [$SN_CONFIG]
   --debug, -d               Enable debugging output
   --verbose, -i             Enable verbose output
   --help, -h                show help
   --version, -v             print the version

Configuration file

Configuration file is optional, and is used to avoid specifying all necessary parameters on the command line. By default, the tool for configuration file in /etc/slack-notify.conf. The configuration file location can be overrided with -f option. Supported formats for configuration file are JSON and YAML.

Example and supported options:

webhook: "https://hooks.slack.com/services/..."
channel: "#random"
username: "slack-notify@myserver"

monit_webhook: "https://hooks.slack.com/services/..."
monit_channel: "#monit"
monit_username: "monit@myserver"

mail_webhook: "https://hooks.slack.com/services/..."
mail_channel: "#srvmail"
mail_username: "mail2slack@myserver"

monit_* and mail_* options are used to override respective options for monit and mail modes.

NOTE: Command line options and environment variables have a higher priority then values specified in configuration file.

msg

Sends a simple test message to slack. Supports markdown formatting.

Example:

$ slack-notify --webhook "https://hooks.slack.com/services/..." --channel "#random" -i msg "Example *message* with _markdown_"
2019-03-04T21:47:21Z Message sent: Example *message* with _markdown_

NOTE: If no message is provided, slack-notify will send a test message.

If configuration file is in place, then the command can be as simple as:

$ slack-notify msg "Example *message* with _markdown_"
$

The message is read from stdin if dash (-) is specified on command line:

$ echo "Example *message* with _markdown_" | slack-notify msg -
$

monit

Sends a monit event to slack.

Configure a check to execute slack-notify on alert:

check filesystem dumpsfs with path /dumps
        if space free < 7GB for 5 cycles then exec "/usr/local/bin/slack-notify monit"
          as uid "nobody" and gid "nobody"
          repeat every 30 cycles
        else if succeeded then exec "/usr/local/bin/slack-notify monit"
          as uid "nobody" and gid "nobody"

NOTE: ensure the configuration file is in place to avoid specifying webhook and channel on the command line as in example above.

If monit triggers the alert, it will appear in slack as follows:

NOTE: If no monit information is defined via environment variables, slack-notify will send a test event.

mail

Reads email from local mbox files and sends to slack. Forwarded emails are deleted from the mailbox. Uses mail from mailx package to read, and remove mail messages.

systemd is used to monitor when the mail is added to the mailbox. Install and activate unit files:

# cp mail2slack\@* /etc/systemd/system/
# systemctl daemon-reload
# systemctl enable mail2slack@root.path --now

Now send a test email:

$ mail -s 'test email' root <<< "Testing that root emails are forwarded to slack automatically."

When the email is added to a mailbox, systemd will run slack-notify:

Mar  4 22:27:31 localhost systemd: Starting mail2slack activator...
Mar  4 22:27:31 localhost slack-notify: 2019-03-04T22:27:31Z Message processed: root@XXXXX -> root@XXXXX | test email
Mar  4 22:27:31 localhost systemd: Started mail2slack activator.

And it will be sent to slack: