# Settings and Environment Variables { #settings-and-environment-variables }

In many cases your application could need some external settings or configurations, for example secret keys, database credentials, credentials for email services, etc.

Most of these settings are variable (can change), like database URLs. And many could be sensitive, like secrets.

For this reason it's common to provide them in environment variables that are read by the application.

/// tip

need it so that empty directory does not get deleted...

  override fun setUseClientMode(mode: Boolean) {
    delegate!!.useClientMode = mode
  }

  override fun getUseClientMode(): Boolean = delegate!!.useClientMode

  override fun setNeedClientAuth(need: Boolean) {
    delegate!!.needClientAuth = need
  }

  override fun setWantClientAuth(want: Boolean) {
    delegate!!.wantClientAuth = want
  }

  override fun getNeedClientAuth(): Boolean = delegate!!.needClientAuth

And an `APIRoute` subclass to use that custom request class.

### Create a custom `GzipRequest` class { #create-a-custom-gziprequest-class }

/// tip

This is a toy example to demonstrate how it works, if you need Gzip support, you can use the provided [`GzipMiddleware`](../advanced/middleware.md#gzipmiddleware){.internal-link target=_blank}.

///

#
# This property uses classification names of classificationDefinitionMap.
# The table name '$$ALL$$' means all tables are target.
# The table names and column names are treated as case insensitive.
#
# You don't need specify here about table classifications.
# Because table classifications are auto-deployed by relation information.
#
# Specification:
# map: {
#     [table-name or $$ALL$$] = map:{

     * @return uses the Maven project and its subprojects
     */
    boolean aggregator() default false;

    /**
     * does this Mojo need to be online to be executed?
     * @return need to be online
     */
    boolean onlineRequired() default false;

    /**
     * TODO: v4: add a SPI for the configurator
     * configurator bean name.

For distributed MinIO deployments, specify the *same* `MINIO_KMS_SECRET_KEY` for each MinIO server process.

At any point in time you can switch from `MINIO_KMS_SECRET_KEY` to a full KMS
deployment. You just need to import the generated key into KES - for example via
the KES CLI once you have successfully setup KES:

```sh
kes key create my-minio-key OSMM+vkKUTCvQs9YL/CVMIMt43HFhkUpqJxTmGl6rYw=
```

### 2. Run distributed MinIO

To start a distributed MinIO instance, you just need to pass drive locations as parameters to the minio server command. Then, you’ll need to run the same command on all the participating nodes.

**NOTE:**

# OpenAPI

There are several utilities to handle OpenAPI.

 * href="https://en.wikipedia.org/wiki/Graph_(discrete_mathematics)">graph</a>-structured data.
 *
 * <p>This interface is meant to be used as the type of a parameter to graph algorithms (such as
 * topological sort) that only need a way of accessing the predecessors of a node in a graph.
 *
 * <h3>Usage</h3>
 *
 * Given an algorithm, for example:
 *
 * {@snippet :