grpc: send client traffic through envoy (#2469)

* wip

* wip

* handle wildcards in override name

* remove wait for ready, add comment about sync, force initial sync complete in test

* address comments

config/envoyconfig/tls.go

@@ -0,0 +1,52 @@
+package envoyconfig
+
+import (
+	"net/url"
+	"regexp"
+	"strings"
+
+	envoy_type_matcher_v3 "github.com/envoyproxy/go-control-plane/envoy/type/matcher/v3"
+)
+
+func (b *Builder) buildSubjectAlternativeNameMatcher(
+	dst *url.URL,
+	overrideName string,
+) *envoy_type_matcher_v3.StringMatcher {
+	sni := dst.Hostname()
+	if overrideName != "" {
+		sni = overrideName
+	}
+
+	if strings.Contains(sni, "*") {
+		pattern := regexp.QuoteMeta(sni)
+		pattern = strings.Replace(pattern, "\\*", ".*", -1)
+		return &envoy_type_matcher_v3.StringMatcher{
+			MatchPattern: &envoy_type_matcher_v3.StringMatcher_SafeRegex{
+				SafeRegex: &envoy_type_matcher_v3.RegexMatcher{
+					EngineType: &envoy_type_matcher_v3.RegexMatcher_GoogleRe2{
+						GoogleRe2: &envoy_type_matcher_v3.RegexMatcher_GoogleRE2{},
+					},
+					Regex: pattern,
+				},
+			},
+		}
+	}
+
+	return &envoy_type_matcher_v3.StringMatcher{
+		MatchPattern: &envoy_type_matcher_v3.StringMatcher_Exact{
+			Exact: sni,
+		},
+	}
+}
+
+func (b *Builder) buildSubjectNameIndication(
+	dst *url.URL,
+	overrideName string,
+) string {
+	sni := dst.Hostname()
+	if overrideName != "" {
+		sni = overrideName
+	}
+	sni = strings.Replace(sni, "*", "example", -1)
+	return sni
+}