John Howard <******@****.***> 1605827959 -0800

1. Config ingestion (inputs to the system)
1. Config translation
1. Config serving (XDS)

### Config Ingestion

Istio reads from over 20 different resources types, and aggregates them together to build the proxy configuration. These resources can be sourced from Kubernetes (via watches), files, or over xDS; Kubernetes is by far the most common usage, though.

Primarily for historical reasons, ingestion is split into a few components.

import java.net.InetAddress
import java.net.UnknownHostException
import okhttp3.HttpUrl.Companion.toHttpUrl
import okhttp3.OkHttpClient

/**
 * Temporary registry of known DNS over HTTPS providers.
 *
 * https://github.com/curl/curl/wiki/DNS-over-HTTPS
 */
object DohProviders {
  private fun buildGoogle(bootstrapClient: OkHttpClient): DnsOverHttps {
    return DnsOverHttps.Builder()
      .client(bootstrapClient)

      }
    } else {
      super.getSelectedProtocol(sslSocket)
    }

  companion object {
    val isSupported: Boolean =
      try {
        // Trigger an early exception over a fatal error, prefer a RuntimeException over Error.
        Class.forName("org.openjsse.net.ssl.OpenJSSE", false, javaClass.classLoader)

        true
      } catch (_: ClassNotFoundException) {
        false
      }

}

// AdmissionResponse describes an admission response.
message AdmissionResponse {
  // UID is an identifier for the individual request/response.
  // This must be copied over from the corresponding AdmissionRequest.
  optional string uid = 1;

  // Allowed indicates whether or not the admission request was permitted.
  optional bool allowed = 2;

participant dep as Abhängigkeit mit yield
participant operation as Pfadoperation
participant tasks as Hintergrundtasks

    Note over client,operation: Kann Exceptions auslösen, inklusive HTTPException
    client ->> dep: Startet den Request
    Note over dep: Führt den Code bis zum yield aus
    opt Löst Exception aus
        dep -->> handler: Löst Exception aus
        handler -->> client: HTTP-Error-Response

  // A list of daemon sets.
  repeated DaemonSet items = 2;
}

// DaemonSetSpec is the specification of a daemon set.
message DaemonSetSpec {
  // A label query over pods that are managed by the daemon set.
  // Must match in order to be controlled.
  // It must match the pod template's labels.

{!../../../docs_src/custom_response/tutorial007.py!}
```

#### Using `StreamingResponse` with file-like objects

If you have a file-like object (e.g. the object returned by `open()`), you can create a generator function to iterate over that file-like object.

That way, you don't have to read it all first in memory, and you can pass that generator function to the `StreamingResponse`, and return it.

 4. If it's a new route, it connects by building either a direct socket connection, a TLS tunnel (for HTTPS over an HTTP proxy), or a direct TLS connection. It does TLS handshakes as necessary. This step may be retried for tunnel challenges and TLS handshake failures.
 5. It sends the HTTP request and reads the response.

/**
 * Reads a stream of [RFC 2046][rfc_2046] multipart body parts. Callers read parts one-at-a-time
 * until [nextPart] returns null. After calling [nextPart] any preceding parts should not be read.
 *
 * Typical use loops over the parts in sequence:
 *
 * ```kotlin
 * val response: Response = call.execute()
 * val multipartReader = MultipartReader(response.body!!)
 *
 * multipartReader.use {
 *   while (true) {