IPv6: Bootstrap extracting of addresses

For Pilot discovery, Zipkin, and statsd addresses, accept IPv6 values,
which will have square brackets.

pkg/bootstrap/bootstrap_config.go

@@ -17,9 +17,9 @@ package bootstrap
import (
	"fmt"
	"io/ioutil"
	"net"
	"os"
	"path"
	"strings"
	"text/template"

	meshconfig "istio.io/api/mesh/v1alpha1"
@@ -72,16 +72,25 @@ func WriteBootstrap(config *meshconfig.ProxyConfig, epoch int, pilotSAN []string
	opts["refresh_delay"] = fmt.Sprintf("{\"seconds\": %d, \"nanos\": %d}", config.DiscoveryRefreshDelay.Seconds, config.DiscoveryRefreshDelay.Nanos)
	opts["connect_timeout"] = fmt.Sprintf("{\"seconds\": %d, \"nanos\": %d}", config.ConnectTimeout.Seconds, config.ConnectTimeout.Nanos)

	addPort := strings.Split(config.DiscoveryAddress, ":")
	opts["pilot_address"] = fmt.Sprintf("{\"address\": \"%s\", \"port_value\": %s}", addPort[0], addPort[1])
	h, p, err := net.SplitHostPort(config.DiscoveryAddress)
	if err != nil {
		return "", fmt.Errorf("PCM: Unable to parse Discovery address %q: %s", config.DiscoveryAddress, err.Error())
	}
	opts["pilot_address"] = fmt.Sprintf("{\"address\": \"%s\", \"port_value\": %s}", h, p)

	if config.ZipkinAddress != "" {
		addPort = strings.Split(config.ZipkinAddress, ":")
		opts["zipkin"] = fmt.Sprintf("{\"address\": \"%s\", \"port_value\": %s}", addPort[0], addPort[1])
		h, p, err := net.SplitHostPort(config.ZipkinAddress)
		if err != nil {
			return "", fmt.Errorf("PCM: Unable to parse Zipkin address %q: %s", config.ZipkinAddress, err.Error())
		}
		opts["zipkin"] = fmt.Sprintf("{\"address\": \"%s\", \"port_value\": %s}", h, p)
	}
	if config.StatsdUdpAddress != "" {
		addPort = strings.Split(config.StatsdUdpAddress, ":")
		opts["statsd"] = fmt.Sprintf("{\"address\": \"%s\", \"port_value\": %s}", addPort[0], addPort[1])
		h, p, err := net.SplitHostPort(config.StatsdUdpAddress)
		if err != nil {
			return "", fmt.Errorf("PCM: Unable to parse StatsdUdp address %q: %s", config.StatsdUdpAddress, err.Error())
		}
		opts["statsd"] = fmt.Sprintf("{\"address\": \"%s\", \"port_value\": %s}", h, p)
	}
	fout, err := os.Create(fname)
	if err != nil {