# Istio Agent

This document describes the internal architecture of Istio agent.

## High Level overview

![High Level overview](docs/overview.svg)

At a high level, the Istio agent acts as an intermediate proxy between Istiod and Envoy. This is done
at two levels. For distributing workload certificates, Envoy will send [SDS](https://www.envoyproxy.io/docs/envoy/latest/configuration/security/secret)

import vcsroots.useAbsoluteVcs

object WarmupEc2Agent : BuildType({
    name = "Warmup EC2 Agent"
    id("Util_WarmupEc2Agent")

    vcs.useAbsoluteVcs(VersionedSettingsBranch.fromDslContext().vcsRootId())

    features {
        freeDiskSpace {
            // Lower the limit such that the agent work directories aren't cleaned during the AMI baking process
            requiredSpace = "100mb"
        }
    }

Envoy Version:       0.0.0

NAME                                                                SERVICE FQDN                          PORT     SUBSET     DIRECTION       TYPE       DESTINATION RULE
cluster/agent                                                       cluster/agent                         -        -          -               STATIC     

val gradlePromotionBranches = "Gradle_GradlePromoteBranches"

fun VcsSettings.useAbsoluteVcs(absoluteId: String) {
    root(AbsoluteId(absoluteId))

    checkoutMode = CheckoutMode.ON_AGENT
    this.cleanCheckout = cleanCheckout
    showDependenciesChanges = true

    )

    /**
     * Modifies the start script injecting -javaagent flags. The start script file is updated in-place by appending Java agent switches to 'DEFAULT_JVM_OPTS' variable declaration.
     */
    private
    fun File.injectAgentOptions(separator: String) {
        if (agentJarNames.isEmpty()) {
            return
        }

Aber eine Variable wie `user-agent` ist in Python nicht gültig.

Darum wird `Header` standardmäßig in Parameternamen den Unterstrich (`_`) zu einem Bindestrich (`-`) konvertieren.

HTTP-Header sind außerdem unabhängig von Groß-/Kleinschreibung, darum können Sie sie mittels der Standard-Python-Schreibweise deklarieren (auch bekannt als "snake_case").

) {
    init {
        id("Promotion_SnapshotFromQuickFeedbackStepPromote")
        name = "Nightly Snapshot (from QuickFeedback) - Promote"
        description = "Promotes a previously built distribution on this agent on '${branch.branchName}' from Quick Feedback as a new nightly snapshot. This build checks out gradle-promote, so don't be misled by the 'master' branch."

        steps {
            buildStep(

    default_type  application/octet-stream;

    log_format  main  '$remote_addr - $remote_user [$time_local] "$request" '
                      '$status $body_bytes_sent "$http_referer" '
                      '"$http_user_agent" "$http_x_forwarded_for"';

    access_log  /var/log/nginx/access.log  main;
    sendfile        on;
    keepalive_timeout  65;

    # include /etc/nginx/conf.d/*.conf;

    upstream minio {

    default_type  application/octet-stream;

    log_format  main  '$remote_addr - $remote_user [$time_local] "$request" '
                      '$status $body_bytes_sent "$http_referer" '
                      '"$http_user_agent" "$http_x_forwarded_for"';

    access_log  /var/log/nginx/access.log  main;
    sendfile        on;
    keepalive_timeout  65;

    # include /etc/nginx/conf.d/*.conf;

    upstream minio {

    default_type  application/octet-stream;

    log_format  main  '$remote_addr - $remote_user [$time_local] "$request" '
                      '$status $body_bytes_sent "$http_referer" '
                      '"$http_user_agent" "$http_x_forwarded_for"';

    access_log  /var/log/nginx/access.log  main;
    sendfile        on;
    keepalive_timeout  65;

    # include /etc/nginx/conf.d/*.conf;

    upstream minio {