Fail2ban - send Slack notifications

jail.local

...

action_with_slack_notification = %(banaction)s[name=%(__name__)s, bantime="%(bantime)s", port="%(port)s", protocol="%(protocol)s", chain="%(chain)s"]
                                 slack[name=%(__name__)s]
                                 
action = %(action_with_slack_notification)s

...

slack.conf

# ADD THIS FILE INTO /etc/fail2ban/actions.d/slack.conf
[Definition]

actioncheck =
actionstart = /bin/bash /etc/fail2ban/slack_notify.sh "The jail <name> has been started successfully." > /dev/null 2>&1
actionstop = /bin/bash /etc/fail2ban/slack_notify.sh "The jail <name> has been stopped." > /dev/null 2>&1
actionban = /bin/bash /etc/fail2ban/slack_notify.sh "Banned _country_ <ip> in the jail <name> after <failures> attempts" "<ip>" > /dev/null 2>&1
actionunban = /bin/bash /etc/fail2ban/slack_notify.sh "Unbanned _country_ <ip> in the jail <name>" "<ip>" > /dev/null 2>&1

# Default name of the chain
#
name = default

slack_notify.sh

#!/bin/bash

# message first command argument
MESSAGE=$1
HOOK_URL=https://hooks.slack.com/services/<your hook url>
HOST=$(hostname)

CHANNEL="#alerts"
USERNAME="fail2ban"
ICON=":cop:"

# ip second command argument
IP=$2
# lets find out from what country we have our hacker
COUNTRY=$(curl ipinfo.io/${IP}/country)
# converting country to lover case. I love you bash script =\
COUNTRY=$(echo "$COUNTRY" | tr -s  '[:upper:]'  '[:lower:]')
# slack emoji
COUNTRY=":flag-$COUNTRY:"

# replace _country_ template to the country emoji
MESSAGE="${MESSAGE/_country_/$COUNTRY}"

curl -X POST --data-urlencode "payload={\"channel\": \"${CHANNEL}\", \"username\": \"${USERNAME}\", \"text\": \"[${HOST}] ${MESSAGE}\", \"icon_emoji\": \"${ICON}\"}" ${HOOK_URL}

exit 0

Hi, I can not get your integration to work.
I edit the jail.local and add the line
action_with_slack_notification =% (banaction) s [name =% (__ name __) s, bantime ="% (bantime) s ", port ="% (port) s ", protocol ="% (protocol) s ", chain =" % (chain) s "] slack [name =% (__ name __) s]

In the same file, I go to the service that I control (SSH).
I add the line
action =% (action_with_slack_notification) s

Now I create in action.d the file slack.conf and I add the lines that you indicate above.
[Definition]

actioncheck =
actionstart = / bin / bash /etc/fail2ban/slack_notify.sh "The jail <name> has been started successfully." > / dev / null 2> & 1
actionstop = / bin / bash /etc/fail2ban/slack_notify.sh "The jail <name> has been stopped." > / dev / null 2> & 1
actionban = / bin / bash /etc/fail2ban/slack_notify.sh "Banned _country_ <ip> in the jail <name> after <failures> attempts" "<ip>"> / dev / null 2> & 1
actionunban = / bin / bash /etc/fail2ban/slack_notify.sh "Unbanned _country_ <ip> in the jail <name>" "<ip>"> / dev / null 2> & 1
# Default name of the chain
name = default

Finally, inside / etc / fail2ban, I create the file slack_notify.sh.
I copy the code you indicate.
I only modify
HOOK_URL = https: //hooks.slack.com/services/XXXXXXXXX/YYYYYYYYY/ZZZZZZZZZZZZZZZZZZZZZZZZ
CHANNEL = "# forexample"

I try to perform a blocking test, but I do not receive the message in the slack channel.

Can you help me with the problem?
Thank you