sds-flow.svg...

digraph {
    envoy -> sds [dir=both, label="SDS"]
    envoy -> xdsproxy  [dir=both, label="ADS"]

    sds -> ca [label="CSR"]

    xdsproxy -> discovery [dir=both,label="ADS"]

    envoy [shape=hexagon, color=purple]

    subgraph cluster_istioagent {
        label = "Istio Agent"
        color="orange"
        sds
        xdsproxy
    }

    subgraph cluster_istiod {
        label = "Istiod"
        color="lightblue"

    subgraph cluster_istioagent {
        label = "Istio Agent"
        color="orange"
        sds
        SecretManager -> caClient [label="Sign CSR"]
        caClient -> grpc
        grpc -> TokenProvider [dir=none,label="Fetch JWT",color=purple]
        grpc -> cfiles [dir=none,label="Fetch Cert",color=purple]

        sds -> SecretManager [label="Generate certificate"]
        SecretManager -> cfiles [label="Write certs to file"]

* If istio-agent does not find either the socket, or the certificate files in their respective paths it will start its own SDS Server using a `caClient` to connect to istiod or an external CA, to fetch cryptographic materials (See Default CA Flow).

![SDS decision flow](docs/sds-flow.svg)

	"istio.io/istio/pkg/test/util/assert"
)

func TestSDSWriter_ValidCert(t *testing.T) {
	testCases := []struct{ sds string }{
		{sds: "istio"},
		{sds: "spire"},
	}
	for _, tc := range testCases {
		t.Run(tc.sds, func(t *testing.T) {
			configDumpFile, err := os.Open(fmt.Sprintf("testdata/secret/%s/config_dump.json", tc.sds))
			if err != nil {
				t.Errorf("error opening test data file: %v", err)
			}
			defer configDumpFile.Close()

                              "grpc_services": [
                                {
                                  "envoy_grpc": {
                                    "cluster_name": "sds-grpc"
                                  }
                                }
                              ],
                              "set_node_on_first_message_only": true,

10.244.0.195:9080                                HEALTHY                  outbound|9080||reviews.default.svc.cluster.local
./var/run/secrets/workload-spiffe-uds/socket     HEALTHY                  sds-grpc
10.244.0.188:11800                               HEALTHY                  outbound|11800||skywalking-oap.skywalking.svc.cluster.local

                                "grpc_services": [
                                  {
                                    "envoy_grpc": {
                                      "cluster_name": "sds-grpc"
                                    }
                                  }
                                ],
                                "set_node_on_first_message_only": true,

               "api_config_source": {
                "api_type": "GRPC",
                "grpc_services": [
                 {
                  "envoy_grpc": {
                   "cluster_name": "sds-grpc"
                  }
                 }
                ],
                "set_node_on_first_message_only": true,
                "transport_api_version": "V3"
               },

	"strings"
	"text/tabwriter"

	adminv3 "github.com/envoyproxy/go-control-plane/envoy/admin/v3"
	"sigs.k8s.io/yaml"

	"istio.io/istio/istioctl/pkg/util/configdump"
	sdscompare "istio.io/istio/istioctl/pkg/writer/compare/sds"
	"istio.io/istio/pkg/util/protomarshal"
)

// ConfigWriter is a writer for processing responses from the Envoy Admin config_dump endpoint
type ConfigWriter struct {
	Stdout     io.Writer
	configDump *configdump.Wrapper