Slack Notifications

[rbrussell82]

Would be nice to have a notification template for Slack Webhooks.

[mag37]

I don't currently have it setup so I can test it myself - but this could work if you'd like to test it out.
Follow the steps at api.slack.com to setup a app and token.

EDITED TO REFLECT OR FINDINGS

### DISCLAIMER: This is a third party addition to dockcheck - best effort testing.
NOTIFY_SLACK_VERSION="v0.1"
#
# Copy/rename this file to notify.sh in the same directory as dockcheck.sh to enable the notification snippet.
# Setu app and token at https://api.slack.com/tutorials/tracks/posting-messages-with-curl
# Add your AccessToken and ChannelID below

FromHost=$(hostname)

trigger_notification() {
    # Modify to fit your setup:
    AccessToken="xoxb-not-a-real-token-this-will-not-work"
    ChannelID="C123456"
    SlackUrl="https://slack.com/api/chat.postMessage"

    curl -sS -o /dev/null --fail \
      -d "text=$MessageBody" -d "channel=$ChannelID" \
      -H "Authorization: Bearer $AccessToken" \
      -X POST $SlackUrl 
}

send_notification() {
    [ -s "$ScriptWorkDir"/urls.list ] && releasenotes || Updates=("$@")
    UpdToString=$( printf '%s\\n' "${Updates[@]}" )

    printf "\nSending Slack notification\n"

    MessageTitle="$FromHost - updates available."
    # Setting the MessageBody variable here.
    printf -v MessageBody "🐋 Containers on $FromHost with updates available:\n$UpdToString"

    trigger_notification
}

### Rename (eg. disabled_dockcheck_notification), remove or comment out the following function
### to not send notifications when dockcheck itself has updates.
dockcheck_notification() {
    printf "\nSending Slack dockcheck notification\n"

    MessageTitle="$FromHost - New version of dockcheck available."
    # Setting the MessageBody variable here.
    printf -v MessageBody "Installed version: $1 \nLatest version: $2 \n\nChangenotes: $3"

    RawNotifyUrl="https://raw.githubusercontent.com/mag37/dockcheck/main/notify_templates/notify_slack.sh"
    LatestNotifyRelease="$(curl -s -r 0-150 $RawNotifyUrl | sed -n "/NOTIFY_SLACK_VERSION/s/NOTIFY_SLACK_VERSION=//p" | tr -d '"')"
    if [[ "$NOTIFY_SLACK_VERSION" != "$LatestNotifyRelease" ]] ; then
        printf -v NotifyUpdate "\n\nnotify_slack.sh update avialable:\n $NOTIFY_SLACK_VERSION -> $LatestNotifyRelease\n"
        MessageBody="${MessageBody}${NotifyUpdate}"
    fi

    trigger_notification
}

[mag37]

I'll need to set up Slack later to be able to test things myself.

What if you insert the exact test curl command in the script, and just replace the text field to be -d "text=$MessageBody"
Like (with your channel and token replaced):

    curl -d "text=$MessageBody" -d "channel=C123456" -H "Authorization: Bearer xoxb-not-a-real-token-this-will-not-work" -X POST https://slack.com/api/chat.postMessage

[rbrussell82]

That helped me figure out the issue. You originally had "text=$MsgBody" and changing it to "text=$MessageBody" works!

EDIT: I just scrolled up and see where you edited one of your replies and caught the same mistake. I should have re-read the previous messages, but it definitely works now :)

[mag37]

Wonderful!
So with the same formatting as in my example but with the corrected $MessageBody?

If so I'll add it to the templates! Thank you kindly for testing it out.

[rbrussell82]

I'm not sure if it made a difference, but I did change the order, so this is what I have:

trigger_notification() {
    # Modify to fit your setup:
    AccessToken="xoxb-not-a-real-token-this-will-not-work"
    ChannelID="C123456"
    SlackUrl="https://slack.com/api/chat.postMessage"

    curl -sS -o /dev/null --show-error --fail \
      -d "text=$MessageBody" -d "channel=$ChannelID" \
      -H "Authorization: Bearer $AccessToken" \
      -X POST $SlackUrl 
}

[mag37]

Superb! Thank you. I'll add it to main in the next patch.