healthchecks/templates/integrations/slack_message.json

{% load hc_extras humanize %}
{
    "username": "{% site_name %}",
    "icon_url": "{% absolute_site_logo_url %}",
    "attachments": [{
        {% if check.status == "up" %}
            "color": "good",
        {% else %}
            "color": "danger",
        {% endif %}

        "fallback": "The check \"{{ check.name_then_code|escapejs }}\" is {{ check.status|upper }}.",
        "mrkdwn_in": ["fields"],
        "title": "“{{ check.name_then_code|escapejs }}” is {{ check.status|upper }}.",
        "title_link": "{{ check.cloaked_url }}",
        "fields": [
            {% if check.desc %}
                {"title": "Description",
                 "value": "{{ check.desc|escapejs }}"
                },
            {% endif %}

            {% if check.project.name %}
                {"title": "Project",
                 "value": "{{ check.project.name|escapejs }}",
                 "short": true
                },
            {% endif %}

            {% if check.tags_list %}
                {"title": "Tags",
                 "value": "{% for tag in check.tags_list %}`{{ tag|escapejs }}` {% endfor %}",
                 "short": true
                },
            {% endif %}

            {% if check.kind == "simple" %}
                {"title": "Period",
                 "value": "{{ check.timeout|hc_duration }}",
                 "short": true
                },
            {% elif check.kind == "cron" %}
                {"title": "Schedule",
                 "value": "{{ check.schedule|fix_asterisks|escapejs }}",
                 "short": true
                },
            {% endif %}

            {"title": "Last Ping",
             {% if check.last_ping %}
               "value": "{{ check.last_ping|naturaltime }}",
             {% else %}
                "value": "Never",
             {% endif %}
             "short": true
            },


            {"title": "Total Pings",
             "value": "{{ check.n_pings }}",
             "short": true
            }
        ]
    }]
}