# 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)

  {{- end }}
  {{- if .Values.global.logAsJson }}
    - --log_as_json
  {{- end }}
    lifecycle:
      postStart:
        exec:
          command:
          - pilot-agent
          - wait
          - --url=http://localhost:15020/healthz/ready
    env:
    - name: ISTIO_META_GENERATOR
      value: grpc
    - name: OUTPUT_CERTS
      value: /var/lib/istio/data

	statusCmd.PersistentFlags().BoolVar(&multiXdsOpts.XdsViaAgents, "xds-via-agents", false,
		"Access Istiod via the tap service of each agent")
	statusCmd.PersistentFlags().IntVar(&multiXdsOpts.XdsViaAgentsLimit, "xds-via-agents-limit", 100,
		"Maximum number of pods being visited by istioctl when `xds-via-agent` flag is true."+
			"To iterate all the agent pods without limit, set to 0")

	return statusCmd

-Dorg.gradle.daemon.idletimeout=120000 -Dorg.gradle.daemon.registry.base=C:\\some\\agent\\workspace\\build\\daemon -Dorg.gradle.native.dir=C:\\some\\agent\\workspace\\intTestHomeDir\\worker-1\\native -Dorg.gradle.deprecation.trace=true -Djava.io.tmpdir=C:\\some\\agent\\workspace\\subprojects\\osgi\\build\\tmp -Dfile.encoding=windows-1252 -Dorg.gradle.classloaderscope.strict=true -ea -ea "-Dorg.gradle.appname=gradle" -classpath "C:\\some\\agent\\workspace\\subprojects\\osgi\\build\\integ test\\bin\\..\\lib\\gra...

                    // The result would be something like DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'" \"-javaagent:$APP_HOME/lib/agents/foobar.jar\""
                    line + getAgentOptions("\$APP_HOME").joinToString(separator = " ", prefix = "\" ", postfix = "\"") {
                        // Wrap the agent switch in double quotes, as the expanded APP_HOME may contain spaces.

    // US region agents have name "EC2-XXX"
    doesNotContain("teamcity.agent.name", "EC2")
}

/**
 * We have some "shared" host where a Linux build agent and a Windows build agent
 * both run on the same bare metal. Some builds require exclusive access to the
 * hardware resources (e.g. performance test).
 */
fun Requirements.requiresNotSharedHost() {
    doesNotContain("agent.host.type", "shared")
}

						" which can be set by `--xds-via-agents-limit` flag.\n", options.XdsViaAgentsLimit)
					break GetProxyLoop
				}
				namespacedName := pod.Name + "." + pod.Namespace
				if visited[namespacedName] {
					// If we already have information about the pod, skip it.
					continue
				}
				resp, err := queryToOnePod(&pod)
				if err != nil {

 *  Fix: Include a backwards-compatible `OkHttp-Response-Source` header with
    `OkUrlFactory `responses.
 *  Fix: Don't include a default User-Agent header in requests made with the Call
    API. Requests made with OkUrlFactory will continue to have a default user
    agent.
 *  New: Guava-like API to create headers:

    ```java
    Headers headers = Headers.of(name1, value1, name2, value2, ...).
    ```

  return reinterpret_cast<TF_CoordinationServiceAgent*>(
      cc_ctx->coordination_service_agent());
}

bool TF_CoordinationServiceIsInitialized(TF_CoordinationServiceAgent* agent) {
  if (agent == nullptr) return false;
  auto* cc_agent = reinterpret_cast<tsl::CoordinationServiceAgent*>(agent);
  return cc_agent->IsInitialized();
}

void TF_CoordinationServiceInsertKeyValue(const char* key, int64_t key_size,

  @Test fun ofMapAcceptsEmptyValue() {
    val headers = mapOf("User-Agent" to "").toHeaders()
    assertThat(headers.value(0)).isEqualTo("")
  }

  @Test fun ofMapTrimsKey() {
    val headers = mapOf(" User-Agent " to "OkHttp").toHeaders()
    assertThat(headers.name(0)).isEqualTo("User-Agent")
  }

  @Test fun ofMapTrimsValue() {
    val headers = mapOf("User-Agent" to " OkHttp ").toHeaders()