Shell/Bash script for sending slack messages.

slack.sh

#!/usr/bin/env bash
####################################################################################
# Slack Bash console script for sending messages.
####################################################################################
# Installation
#    $ curl -s https://gist.githubusercontent.com/andkirby/67a774513215d7ba06384186dd441d9e/raw --output /usr/bin/slack
#    $ chmod +x /usr/bin/slack
####################################################################################
# USAGE
# Send message to slack channel/user
#   Send a message to the channel #ch-01
#     $ slack '#ch-01' 'Some message here.'
#
#   Send a message to the channel #ch-01 and user @me.
#     $ slack '#ch-01,@me' MESSAGE
#
#   Send a message to the default channel (it must be declared in APP_SLACK_CHANNEL).
#     $ slack  MESSAGE
#
# VARIABLES
#
# Please declare environment variables:
#   - APP_SLACK_WEBHOOK
#   - APP_SLACK_CHANNEL (optional)
#   - APP_SLACK_USERNAME (optional)
#   - APP_SLACK_ICON_EMOJI (optional)
# You may also declare them in ~/.slackrc file.
####################################################################################

set -o pipefail
set -o errexit
set -o nounset
#set -o xtrace

init_params() {
  # you may declare ENV vars in /etc/profile.d/slack.sh
  if [ -z "${APP_SLACK_WEBHOOK:-}" ]; then
    echo 'error: Please configure Slack environment variable: ' > /dev/stderr
    echo '  APP_SLACK_WEBHOOK' > /dev/stderr
    exit 2
  fi

  APP_SLACK_USERNAME=${APP_SLACK_USERNAME:-$(hostname | cut -d '.' -f 1)}

  APP_SLACK_ICON_EMOJI=${APP_SLACK_ICON_EMOJI:-:slack:}
  if [ -z "${1:-}" ]; then
    echo 'error: Missed required arguments.' > /dev/stderr
    echo 'note: Please follow this example:' > /dev/stderr
    echo '  $ slack.sh "#CHANNEL1,CHANNEL2" Some message here. ' > /dev/stderr
    exit 3
  fi

  slack_channels=(${APP_SLACK_CHANNEL:-})
  if [ "${1::1}" == '#' ] || [ "${1::1}" == '@' ]; then
    # explode by comma
    IFS=',' read -r -a slack_channels <<< "${1}"
    shift
  fi
  slack_message=${@}
}


send_message() {
  local channel=${1}
  echo 'Sending to '${channel}'...'
  curl --silent --data-urlencode \
    "$(printf 'payload={"text": "%s", "channel": "%s", "username": "%s", "as_user": "true", "link_names": "true", "icon_emoji": "%s" }' \
        "${slack_message}" \
        "${channel}" \
        "${APP_SLACK_USERNAME}" \
        "${APP_SLACK_ICON_EMOJI}" \
    )" \
    ${APP_SLACK_WEBHOOK} || true
  echo
}

send_message_to_channels() {
  for channel in "${slack_channels[@]:-}"; do
    send_message "${channel}"
  done
}

slack() {
  # Set magic variables for current file & dir
  __dir="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
  __file="${__dir}/$(basename "${BASH_SOURCE[0]}")"
  readonly __dir __file

  cd ${__dir}

  if [ -f $(cd; pwd)/.slackrc ]; then
    . $(cd; pwd)/.slackrc
  fi

  declare -a slack_channels

  init_params ${@}
  send_message_to_channels
}

if [ "${BASH_SOURCE[0]:-}" != "${0}" ]; then
  export -f slack
else
  slack ${@}
  exit $?
fi

Just an insight to those facing issues with /usr/bin/slack due to permission accessing to /usr/bin, you can move the script under usr/local/bin/slack.

So that the two commands to run will be:

curl -s https://gist.githubusercontent.com/andkirby/67a774513215d7ba06384186dd441d9e/raw --output /usr/local/bin/slack

chmod +x /usr/local/bin/slack

hope it helps 👍
great script @andkirby 💪

Hi,

when sending a message in this way:
slack.sh ":arrow_right: data seeding"
emoji appears as text and it is not rendered, what am I doing wrong ?
Thanks!

emoji appears as text and it is not rendered, what am I doing wrong ?

@jmhostalet, I assume, they added mrkdwn type for that.
https://api.slack.com/reference/surfaces/formatting#basics

great script @andkirby 💪

@d4r1091, it's a pleasure to know it. ;)

@jmhostalet, just double check it. It works with emoji. According to off-docs mrkdwn=true always.

hi @andkirby

I want to ask, why can I sent from grep command?

my sh script like this :

#!/bin/bash
message=$(grep AUDIT audit.txt)
slack ${message}

if I execute this, I always get this error:

/home/ubuntu# ./test_sent.sh
Sending to ...
invalid_payload

can you solve this?