PD-5477: CPC overview text

Content/liquibase-pro/policy-checks/custom-policy-checks/home.htm

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         <h1>Custom Policy Checks</h1>
         <p>Custom Policy Checks are Python scripts that allow you run advanced policies using the <MadCap:variable name="General.Liquibase" />&#160;<MadCap:xref href="../home.htm">Policy Checks</MadCap:xref> framework. Custom policy checks allow you to enforce compliance for a wide array of security, code standards, data quality, and more.</p>
-        <p>While it's possible to configure the behavior of many <a href="../checks/home.htm">built-in <MadCap:variable name="General.Liquibase" /> policy checks</a>, those checks have a limited scope. In contrast, you can use custom policy checks to create unique checks for any situation in your <MadCap:variable name="General.Liquibase" /> workflow.</p>
+        <p>While it's possible to configure the behavior of many <a href="../checks/home.htm">built-in <MadCap:variable name="General.Liquibase" /> policy checks</a> using regular expressions, those checks only work for predefined use-cases. Sometimes, they might not be robust enough for your needs. In contrast, you can use custom policy checks to create unique checks for any situation in your <MadCap:variable name="General.Liquibase" /> workflow.</p>
         <p class="note" MadCap:autonum="&lt;b&gt;Note: &lt;/b&gt;">This is a <MadCap:variable name="General.LBPro"></MadCap:variable> feature, so you need a <a href="https://docs.liquibase.com/workflows/liquibase-pro/how-to-apply-your-liquibase-pro-license-key.html" target="_blank"><MadCap:variable name="General.LBPro"></MadCap:variable> License Key</a> to use it.</p>
+        <h2>Quickstart: Create a custom policy check</h2>
+        <p>For a step-by-step tutorial, see <MadCap:xref href="tutorial.htm">Create a Custom Policy Check</MadCap:xref>.</p>
+        <h2>Overview</h2>
+        <h3><MadCap:variable name="General.Liquibase" /> checks framework</h3>
+        <p>The logic of a custom policy check is stored in a Python (<code class="language-text">.py</code>) script file in your <MadCap:variable name="General.Liquibase" /> working directory. You can write and modify that script without using <MadCap:variable name="General.Liquibase" /> commands:&#160;it's just a Python file. You should keep the logic for different checks in different Python files.</p>
+        <p>You can integrate your Python file into <MadCap:variable name="General.Liquibase" /> by using the same <MadCap:xref href="../../../commands/policy-checks/subcommands/home.htm">Policy Checks Commands</MadCap:xref> you would use to copy a built-in policy check. Specifically, there is a built-in policy check called <code class="language-text">CustomChecksTemplate</code> that you can <MadCap:xref href="../../../commands/policy-checks/subcommands/copy.htm">copy</MadCap:xref> and <MadCap:xref href="../../../commands/policy-checks/subcommands/customize.htm">customize</MadCap:xref> to specify your own logic. In the CLI, you specify a short name for your custom check in <MadCap:variable name="General.Liquibase" />, the Python script containing the check logic to run, and other configurations like the check's severity level.</p>
+        <p>Since a custom policy check runs in the <MadCap:variable name="General.Liquibase" /> policy checks framework, you can <a href="../workflows/automation-severity-exit-code.htm">deploy custom policy checks into your CI/CD&#160;automation</a> the same way as built-in checks. This allows your code to be robust but keeps your processes simple.</p>
+        <h3>Python script looping</h3>
+        <p><MadCap:variable name="General.Liquibase" /> always runs every enabled policy check against <b>every object the check targets</b>. This works the same for custom policy checks. For example, <MadCap:variable name="General.Liquibase" /> runs any custom policy check with a scope of:</p>
+        <ul>
+            <li><code class="language-text">changelog</code>: <b>once per <MadCap:variable name="General.changeset" /></b> in that <MadCap:variable name="General.changelog" />. If the <MadCap:variable name="General.changelog" /> uses <code><MadCap:xref href="../../../change-types/include.html">include</MadCap:xref></code> or <code><MadCap:xref href="../../../change-types/includeall.html">includeAll</MadCap:xref></code> to reference child <MadCap:variable name="General.changelog" />s, the script also runs once per <MadCap:variable name="General.changeset" /> in each of those <MadCap:variable name="General.changelog" />s.</li>
+            <li><code class="language-text">database</code>: <b>once per database object</b>. &lt;within a schema?&#160;what about multiple schemas?&gt;</li>
+        </ul>
+        <p class="warning" MadCap:autonum="&lt;b&gt;Warning: &lt;/b&gt;">If you write a custom policy check that is individually performance-heavy, and you have a very large <MadCap:variable name="General.changelog" /> or database, <MadCap:variable name="General.Liquibase" /> may take a long time to run your custom check iteratively.</p>
+        <h3>Python helper scripts</h3>
+        <p><MadCap:variable name="General.Liquibase" /> has a public API that you can import in your Python scripts in order to access a library of <MadCap:variable name="General.Liquibase" /> helper scripts. For example, there are helper scripts to find the author of a <MadCap:variable name="General.changeset" /> and to determine whether a database object is a table.</p>
+        <p>Using helper scripts makes it easier to access information in <MadCap:variable name="General.Liquibase" /> resources and your database. This way, you can keep your Python scripts concise.</p>
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