{% extends "base.html" %}
{% load staticfiles %}

{% block title %}Documentation - healthchecks.io{% endblock %}

{% block content %}
<div class="row">
    <div class="col-sm-12">
        <h3>Summary</h3>
        <p>
        Each check you create in <a href="{% url 'hc-index' %}">My Checks</a>
        page has an unique "ping" URL. Whenever you access this URL,
        the "Last Ping" value of corresponding check is updated.
        </p>
        <p>When a certain amount of time passes since last received ping, the
        check is considered "late", and Health Checks sends an email alert.
        It is all very simple, really.</p>

        <h3>Executing a Ping</h3>
        <p>
            At the end of your batch job, add a bit of code to request
            one of your ping URLs.
        </p>
        <ul>
            <li>HTTP and HTTPS protocols both are fine</li>
            <li>Request method can be GET or POST</li>
            <li>It does not matter what request headers you send</li>
            <li>You can leave request body empty or put anything in it, it's all good</li>
        </ul>

        <p>The response will have status code "200 OK" and response body will be a
        short and simple string "OK".</p>

        <p>
            In bash scripts, you can use <code>wget</code> or <code>curl</code> to run the requests:
        </p>
        <pre>
curl {{ ping_endpoint }}{uuid-goes-here}
</pre>

        <h3>When Alerts Are Sent</h3>
        <p>
            Each check has a configurable <strong>Period</strong> parameter, with the default value of one day.
            For periodic tasks, this is the expected time gap between two runs.
        </p>
        <p>
            Additionally, each check has a <strong>Grace</strong> parameter, with default value of one hour.
            You can use this parameter to account for run time variance of tasks.
            For example, if a backup task completes in 50 seconds one day, and
            completes in 60 seconds the following day, you might not want to get
            alerted because the backups are 10 seconds late.
        </p>
        <p>Each check can be in one of the following states:</p>

        <table class="table">
            <tr>
                <td>
                    <span class="glyphicon glyphicon-question-sign new"></span>
                </td>
                <td>
                    <strong>New.</strong>
                    A check that has been created, but has not received any pings yet.
                </td>
            </tr>
            <tr>
                <td>
                    <span class="glyphicon glyphicon-ok-sign up"></span>
                </td>
                <td>
                    <strong>Up.</strong>
                    Time since last ping has not exceeded <strong>Period</strong>.
                </td>
            </tr>
            <tr>
                <td>
                    <span class="glyphicon glyphicon-exclamation-sign grace"></span>
                </td>
                <td>
                    <strong>Late.</strong>
                    Time since last ping has exceeded <strong>Period</strong>,
                    but has not yet exceeded <strong>Period</strong> + <strong>Grace</strong>.
                </td>
            </tr>
            <tr>
                <td>
                    <span class="glyphicon glyphicon-exclamation-sign down"></span>
                </td>
                <td>
                    <strong>Down.</strong>
                    Time since last ping has exceeded <strong>Period</strong> + <strong>Grace</strong>.
                    When check goes from "Late" to "Down", healthchecks.io
                    sends you an email alert.
                </td>
            </tr>
        </table>

    </div>
</div>
{% endblock %}