* `COMPATIBLE_TLS` is a secure configuration that connects to secure–but not current–HTTPS servers.
 * `CLEARTEXT` is an insecure configuration that is used for `http://` URLs.

These loosely follow the model set in [Google Cloud Policies](https://cloud.google.com/load-balancing/docs/ssl-policies-concepts). We [track changes](../security/tls_configuration_history.md) to this policy.

## An app with callbacks { #an-app-with-callbacks }

Let's see all this with an example.

Imagine you develop an app that allows creating invoices.

These invoices will have an `id`, `title` (optional), `customer`, and `total`.

The user of your API (an external developer) will create an invoice in your API with a POST request.

Then your API will (let's imagine):

As you saw in the previous chapter about [Deployment Concepts](concepts.md){.internal-link target=_blank}, there are multiple strategies you can use.

Here I'll show you how to use **Uvicorn** with **worker processes** using the `fastapi` command or the `uvicorn` command directly.

/// info

   * escaper that is created will be a snapshot of the current builder state. Builders are not
   * thread safe.
   *
   * <p>The initial state of the builder is such that:
   *
   * <ul>
   *   <li>There are no replacement mappings
   *   <li>{@code safeMin == Character.MIN_VALUE}
   *   <li>{@code safeMax == Character.MAX_VALUE}
   *   <li>{@code unsafeReplacement == null}
   * </ul>
   *

 * dynamicProperties.setProperty("key", "newValue");
 * dynamicProperties.store();
 * </pre>
 *
 * <p>Exceptions:
 * <ul>
 *   <li>{@link FileAccessException} - Thrown if there are issues accessing the file.</li>
 *   <li>{@link IORuntimeException} - Thrown if there are I/O errors during file operations.</li>
 * </ul>
 *
 * <p>Thread Safety:
 * This class uses synchronization to ensure thread-safe access to the properties.
 *

	// (Optional) Extra (constant) label KV pairs to be added to each metric in
	// the group.
	ExtraLabels map[string]string

	// Loader functions to load metrics. Only one of these will be set. Metrics
	// returned by these functions must be present in the `Descriptors` list.
	loader       MetricsLoaderFn
	bucketLoader BucketMetricsLoaderFn

	// Cache for all metrics groups. Set via `.SetCache` method.

pod priority and pod preemption. These features allow mixing various types of workloads in a single cluster, and help reach
higher levels of resource utilization and availability.
These features are in alpha. SIG Scheduling also improved the internal APIs for scheduling and made them easier for other components and external schedulers to use.

	// at any given point in time. This allows different buckets to be scanned
	// in different order per erasure set, this wider spread is needed when
	// there are lots of buckets with different order of objects in them.
	r := rand.New(rand.NewSource(time.Now().UnixNano()))
	permutes := r.Perm(len(buckets))
	// Add new buckets first
	for _, idx := range permutes {
		b := buckets[idx]

				success := true
				if err := r.ReplicateFromSource(ctx, api, core, oi, retry); err != nil {
					// object must be deleted concurrently, allow these failures but do not count them
					if isErrVersionNotFound(err) || isErrObjectNotFound(err) {
						return
					}
					stopFn(oi, err)
					batchLogIf(ctx, err)
					success = false
				} else {
					stopFn(oi, nil)

	// defined parameter to disambiguate the intended IDP in this STS request.
	roleArn := openid.DummyRoleARN
	roleArnStr := r.Form.Get(stsRoleArn)
	isRolePolicyProvider := roleArnStr != ""
	if isRolePolicyProvider {
		var err error
		roleArn, _, err = globalIAMSys.GetRolePolicy(roleArnStr)
		if err != nil {
			// If there is no claim-based provider configured, then an