TUN-3456: New protocol option auto to automatically select between http2 and h2mux

edgediscovery/protocol.go

@@ -0,0 +1,45 @@
+package edgediscovery
+
+import (
+	"fmt"
+	"net"
+	"strconv"
+	"strings"
+)
+
+const (
+	protocolRecord = "protocol.argotunnel.com"
+)
+
+var (
+	errNoProtocolRecord = fmt.Errorf("No TXT record found for %s to determine connection protocol", protocolRecord)
+)
+
+func HTTP2Percentage() (int32, error) {
+	records, err := net.LookupTXT(protocolRecord)
+	if err != nil {
+		return 0, err
+	}
+	if len(records) == 0 {
+		return 0, errNoProtocolRecord
+	}
+	return parseHTTP2Precentage(records[0])
+}
+
+// The record looks like http2=percentage
+func parseHTTP2Precentage(record string) (int32, error) {
+	const key = "http2"
+	slices := strings.Split(record, "=")
+	if len(slices) != 2 {
+		return 0, fmt.Errorf("Malformed TXT record %s, expect http2=percentage", record)
+	}
+	if slices[0] != key {
+		return 0, fmt.Errorf("Incorrect key %s, expect %s", slices[0], key)
+	}
+	percentage, err := strconv.ParseInt(slices[1], 10, 32)
+	if err != nil {
+		return 0, err
+	}
+	return int32(percentage), nil
+
+}

edgediscovery/protocol_test.go

@@ -0,0 +1,80 @@
+package edgediscovery
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestHTTP2Percentage(t *testing.T) {
+	_, err := HTTP2Percentage()
+	assert.NoError(t, err)
+}
+
+func TestParseHTTP2Precentage(t *testing.T) {
+	tests := []struct {
+		record     string
+		percentage int32
+		wantErr    bool
+	}{
+		{
+			record:     "http2=-1",
+			percentage: -1,
+			wantErr:    false,
+		},
+		{
+			record:     "http2=0",
+			percentage: 0,
+			wantErr:    false,
+		},
+		{
+			record:     "http2=50",
+			percentage: 50,
+			wantErr:    false,
+		},
+		{
+			record:     "http2=100",
+			percentage: 100,
+			wantErr:    false,
+		},
+		{
+			record:     "http2=1000",
+			percentage: 1000,
+			wantErr:    false,
+		},
+		{
+			record:  "http2=10.5",
+			wantErr: true,
+		},
+		{
+			record:  "http2=10 h2mux=90",
+			wantErr: true,
+		},
+		{
+			record:  "http2=ten",
+			wantErr: true,
+		},
+
+		{
+			record:  "h2mux=100",
+			wantErr: true,
+		},
+		{
+			record:  "http2",
+			wantErr: true,
+		},
+		{
+			record:  "http2=",
+			wantErr: true,
+		},
+	}
+
+	for _, test := range tests {
+		p, err := parseHTTP2Precentage(test.record)
+		if test.wantErr {
+			assert.Error(t, err)
+		} else {
+			assert.Equal(t, test.percentage, p)
+		}
+	}
+}