docs(product): add configuration example for Row-Level Security (#7004)

Author: hassankhan

docs/docs-new/pages/product/apis-integrations/sql-api/security.mdx

@@ -38,29 +38,139 @@ additional security.
 
 Cube's SQL API can also use the Security Context for [Dynamic data model
 creation][ref-dynamic-schemas] or [`queryRewrite`][ref-config-queryrewrite]
-property in your [`cube.js` configuration file][ref-config-js].
+property in your `cube.js` configuration file.
 
 By default, the SQL API uses the current user's Security Context, but this
 behaviour can be modified so that certain users are allowed to switch. To do
 this, we must first define which user is allowed to change Security Context:
 
+### Example
+
 First, you need to define what user is allowed to change security context:
 
 ```dotenv
 CUBEJS_SQL_SUPER_USER=admin
 ```
 
+Then configure the [`contextToAppId()`][ref-config-ctx-to-app-id],
+[`queryRewrite()`][ref-config-queryrewrite] and
+[`checkSqlAuth()`][ref-config-check-sql-auth] properties in your `cube.js`
+configuration file:
+
+```javascript filename="cube.js"
+module.exports = {
+  // Create a new appId for each team, this prevents teams from seeing each
+  // other's data
+  // https://cube.dev/docs/reference/configuration/config#contexttoappid
+  contextToAppId: ({ securityContext }) => {
+    return securityContext.team;
+  },
+
+  // Enforce a default value for `team` if one is not provided
+  // in the security context
+  // https://cube.dev/docs/reference/configuration/config#extendcontext
+  extendContext: ({ securityContext }) => {
+    if (!securityContext.team) {
+      securityContext.team = "public";
+    }
+
+    return {
+      securityContext,
+    };
+  },
+
+  // Here we create a new security context for each team so that we can
+  // use it in our data model later
+  checkSqlAuth: (query, username) => {
+    const securityContext = {
+      team: username,
+    };
+
+    return {
+      password: process.env.CUBEJS_SQL_PASSWORD,
+      securityContext: securityContext,
+    };
+  },
+};
+```
+
+Now, you can use the `securityContext` in your data model:
+
+```twig filename="model/cubes/users.yml.jinja"
+{# Is the current team trusted? #}
+{% set trusted_teams = ['cx', 'exec' ] %}
+{% set is_trusted_team = COMPILE_CONTEXT.securityContext.team in trusted_teams %}
+
+{# Convenient function to mask values if the current team is not trusted #}
+{% macro masked(sql, is_visible) -%}
+{{ sql if is_visible else "\"'--- masked ---'\"" }}
+{%- endmacro %}
+
+cubes:
+  - name: users
+    sql_table: users
+    public: false
+
+    dimensions:
+
+      {# This property will be masked unless the requesting user is part of a trusted team #}
+      - name: first_name
+        sql: {{ masked('first_name', is_trusted_team) }}
+        type: string
+
+      {# This property will be masked unless the requesting user is part of a trusted team #}
+      - name: last_name
+        sql: {{ masked('last_name', is_trusted_team) }}
+        type: string
+
+      - name: state
+        sql: state
+        type: string
+
+      - name: city
+        sql: city
+        type: string
+
+      - name: created_at
+        sql: created_at
+        type: time
+
+    measures:
+      - name: count
+        type: count
+
+```
+
+With the above now configured, we can query Cube using SQL with a user that is
+part of a trusted team:
+
+```sql
+SELECT users_city, users_first_name, users_last_name
+FROM users
+WHERE __user = 'cx'
+```
+
+This pairs well with other security functionality in tools like Preset, which
+allows configuring [row-level security to allow
+access][preset-docs-rls-inclusive] to data based on the current user's security
+context.
+
 If it's not enough for your case, you define your logic for check with
-`canSwitchSqlUser` property in your [`cube.js` configuration
-file][ref-config-js].
+[`canSwitchSqlUser` property][ref-config-can-switch-sql-user] in your `cube.js`
+configuration file.
 
 You can change security context for specific query via virtual filter on:
 
 ```sql
 SELECT * FROM orders WHERE __user = 'anotheruser';
 ```
 
+[preset-docs-rls-inclusive]:
+  https://docs.preset.io/docs/row-level-security-rls#define-inclusive-regular-rls-filter
+[ref-config-can-switch-sql-user]:
+  /reference/configuration/config#canswitchsqluser
 [ref-config-check-sql-auth]: /reference/configuration/config#checksqlauth
+[ref-config-ctx-to-app-id]: /reference/configuration/config#contexttoappid
 [ref-config-queryrewrite]: /reference/configuration/config#queryrewrite
 [ref-dynamic-schemas]: /schema/dynamic-schema-creation
 [ref-config-js]: /reference/configuration/config