cloudflared-mirror/origin/tunnel.go

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package origin
import (
"bufio"
"context"
"crypto/tls"
"fmt"
"io"
"net"
"net/http"
"net/url"
"strconv"
"strings"
"sync"
"time"
"github.com/cloudflare/cloudflared/h2mux"
"github.com/cloudflare/cloudflared/tunnelrpc"
tunnelpogs "github.com/cloudflare/cloudflared/tunnelrpc/pogs"
"github.com/cloudflare/cloudflared/validation"
"github.com/cloudflare/cloudflared/websocket"
raven "github.com/getsentry/raven-go"
"github.com/google/uuid"
"github.com/pkg/errors"
_ "github.com/prometheus/client_golang/prometheus"
log "github.com/sirupsen/logrus"
"golang.org/x/sync/errgroup"
rpc "zombiezen.com/go/capnproto2/rpc"
)
const (
dialTimeout = 15 * time.Second
lbProbeUserAgentPrefix = "Mozilla/5.0 (compatible; Cloudflare-Traffic-Manager/1.0; +https://www.cloudflare.com/traffic-manager/;"
TagHeaderNamePrefix = "Cf-Warp-Tag-"
DuplicateConnectionError = "EDUPCONN"
)
type TunnelConfig struct {
EdgeAddrs []string
OriginUrl string
Hostname string
OriginCert []byte
TlsConfig *tls.Config
ClientTlsConfig *tls.Config
Retries uint
HeartbeatInterval time.Duration
MaxHeartbeats uint64
ClientID string
BuildInfo *BuildInfo
ReportedVersion string
LBPool string
Tags []tunnelpogs.Tag
HAConnections int
HTTPTransport http.RoundTripper
Metrics *TunnelMetrics
MetricsUpdateFreq time.Duration
TransportLogger *log.Logger
Logger *log.Logger
IsAutoupdated bool
GracePeriod time.Duration
RunFromTerminal bool
NoChunkedEncoding bool
WSGI bool
CompressionQuality uint64
IncidentLookup IncidentLookup
CloseConnOnce *sync.Once // Used to close connectedSignal no more than once
}
type dialError struct {
cause error
}
func (e dialError) Error() string {
return e.cause.Error()
}
type dupConnRegisterTunnelError struct{}
func (e dupConnRegisterTunnelError) Error() string {
return "already connected to this server"
}
type muxerShutdownError struct{}
func (e muxerShutdownError) Error() string {
return "muxer shutdown"
}
// RegisterTunnel error from server
type serverRegisterTunnelError struct {
cause error
permanent bool
}
func (e serverRegisterTunnelError) Error() string {
return e.cause.Error()
}
// RegisterTunnel error from client
type clientRegisterTunnelError struct {
cause error
}
func (e clientRegisterTunnelError) Error() string {
return e.cause.Error()
}
func (c *TunnelConfig) RegistrationOptions(connectionID uint8, OriginLocalIP string, uuid uuid.UUID) *tunnelpogs.RegistrationOptions {
policy := tunnelrpc.ExistingTunnelPolicy_balance
if c.HAConnections <= 1 && c.LBPool == "" {
policy = tunnelrpc.ExistingTunnelPolicy_disconnect
}
return &tunnelpogs.RegistrationOptions{
ClientID: c.ClientID,
Version: c.ReportedVersion,
OS: fmt.Sprintf("%s_%s", c.BuildInfo.GoOS, c.BuildInfo.GoArch),
ExistingTunnelPolicy: policy,
PoolName: c.LBPool,
Tags: c.Tags,
ConnectionID: connectionID,
OriginLocalIP: OriginLocalIP,
IsAutoupdated: c.IsAutoupdated,
RunFromTerminal: c.RunFromTerminal,
CompressionQuality: c.CompressionQuality,
UUID: uuid.String(),
}
}
func StartTunnelDaemon(config *TunnelConfig, shutdownC <-chan struct{}, connectedSignal chan struct{}) error {
ctx, cancel := context.WithCancel(context.Background())
go func() {
<-shutdownC
cancel()
}()
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u, err := uuid.NewRandom()
if err != nil {
return err
}
// If a user specified negative HAConnections, we will treat it as requesting 1 connection
if config.HAConnections > 1 {
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return NewSupervisor(config).Run(ctx, connectedSignal, u)
} else {
addrs, err := ResolveEdgeIPs(config.EdgeAddrs)
if err != nil {
return err
}
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return ServeTunnelLoop(ctx, config, addrs[0], 0, connectedSignal, u)
}
}
func ServeTunnelLoop(ctx context.Context,
config *TunnelConfig,
addr *net.TCPAddr,
connectionID uint8,
connectedSignal chan struct{},
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u uuid.UUID,
) error {
logger := config.Logger
config.Metrics.incrementHaConnections()
defer config.Metrics.decrementHaConnections()
backoff := BackoffHandler{MaxRetries: config.Retries}
connectedFuse := h2mux.NewBooleanFuse()
go func() {
if connectedFuse.Await() {
config.CloseConnOnce.Do(func() { close(connectedSignal) })
}
}()
// Ensure the above goroutine will terminate if we return without connecting
defer connectedFuse.Fuse(false)
for {
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err, recoverable := ServeTunnel(ctx, config, addr, connectionID, connectedFuse, &backoff, u)
if recoverable {
if duration, ok := backoff.GetBackoffDuration(ctx); ok {
logger.Infof("Retrying in %s seconds", duration)
backoff.Backoff(ctx)
continue
}
}
return err
}
}
func ServeTunnel(
ctx context.Context,
config *TunnelConfig,
addr *net.TCPAddr,
connectionID uint8,
connectedFuse *h2mux.BooleanFuse,
backoff *BackoffHandler,
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u uuid.UUID,
) (err error, recoverable bool) {
// Treat panics as recoverable errors
defer func() {
if r := recover(); r != nil {
var ok bool
err, ok = r.(error)
if !ok {
err = fmt.Errorf("ServeTunnel: %v", r)
}
recoverable = true
}
}()
connectionTag := uint8ToString(connectionID)
logger := config.Logger.WithField("connectionID", connectionTag)
// additional tags to send other than hostname which is set in cloudflared main package
tags := make(map[string]string)
tags["ha"] = connectionTag
// Returns error from parsing the origin URL or handshake errors
handler, originLocalIP, err := NewTunnelHandler(ctx, config, addr.String(), connectionID)
if err != nil {
errLog := config.Logger.WithError(err)
switch err.(type) {
case dialError:
errLog.Error("Unable to dial edge")
case h2mux.MuxerHandshakeError:
errLog.Error("Handshake failed with edge server")
default:
errLog.Error("Tunnel creation failure")
return err, false
}
return err, true
}
errGroup, serveCtx := errgroup.WithContext(ctx)
errGroup.Go(func() error {
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err := RegisterTunnel(serveCtx, handler.muxer, config, connectionID, originLocalIP, u)
if err == nil {
connectedFuse.Fuse(true)
backoff.SetGracePeriod()
}
return err
})
errGroup.Go(func() error {
updateMetricsTickC := time.Tick(config.MetricsUpdateFreq)
for {
select {
case <-serveCtx.Done():
// UnregisterTunnel blocks until the RPC call returns
err := UnregisterTunnel(handler.muxer, config.GracePeriod, config.TransportLogger)
handler.muxer.Shutdown()
return err
case <-updateMetricsTickC:
handler.UpdateMetrics(connectionTag)
}
}
})
errGroup.Go(func() error {
// All routines should stop when muxer finish serving. When muxer is shutdown
// gracefully, it doesn't return an error, so we need to return errMuxerShutdown
// here to notify other routines to stop
err := handler.muxer.Serve(serveCtx)
if err == nil {
return muxerShutdownError{}
}
return err
})
err = errGroup.Wait()
if err != nil {
switch castedErr := err.(type) {
case dupConnRegisterTunnelError:
logger.Info("Already connected to this server, selecting a different one")
return err, true
case serverRegisterTunnelError:
logger.WithError(castedErr.cause).Error("Register tunnel error from server side")
// Don't send registration error return from server to Sentry. They are
// logged on server side
if incidents := config.IncidentLookup.ActiveIncidents(); len(incidents) > 0 {
logger.Error(activeIncidentsMsg(incidents))
}
return castedErr.cause, !castedErr.permanent
case clientRegisterTunnelError:
logger.WithError(castedErr.cause).Error("Register tunnel error on client side")
raven.CaptureError(castedErr.cause, tags)
return err, true
case muxerShutdownError:
logger.Infof("Muxer shutdown")
return err, true
default:
logger.WithError(err).Error("Serve tunnel error")
raven.CaptureError(err, tags)
return err, true
}
}
return nil, true
}
func IsRPCStreamResponse(headers []h2mux.Header) bool {
if len(headers) != 1 {
return false
}
if headers[0].Name != ":status" || headers[0].Value != "200" {
return false
}
return true
}
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func RegisterTunnel(
ctx context.Context,
muxer *h2mux.Muxer,
config *TunnelConfig,
connectionID uint8,
originLocalIP string,
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uuid uuid.UUID,
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) error {
config.TransportLogger.Debug("initiating RPC stream to register")
stream, err := muxer.OpenStream([]h2mux.Header{
{Name: ":method", Value: "RPC"},
{Name: ":scheme", Value: "capnp"},
{Name: ":path", Value: "*"},
}, nil)
if err != nil {
// RPC stream open error
return clientRegisterTunnelError{cause: err}
}
if !IsRPCStreamResponse(stream.Headers) {
// stream response error
return clientRegisterTunnelError{cause: err}
}
conn := rpc.NewConn(
tunnelrpc.NewTransportLogger(config.TransportLogger.WithField("subsystem", "rpc-register"), rpc.StreamTransport(stream)),
tunnelrpc.ConnLog(config.TransportLogger.WithField("subsystem", "rpc-transport")),
)
defer conn.Close()
ts := tunnelpogs.TunnelServer_PogsClient{Client: conn.Bootstrap(ctx)}
// Request server info without blocking tunnel registration; must use capnp library directly.
tsClient := tunnelrpc.TunnelServer{Client: ts.Client}
serverInfoPromise := tsClient.GetServerInfo(ctx, func(tunnelrpc.TunnelServer_getServerInfo_Params) error {
return nil
})
registration, err := ts.RegisterTunnel(
ctx,
config.OriginCert,
config.Hostname,
config.RegistrationOptions(connectionID, originLocalIP, uuid),
)
LogServerInfo(serverInfoPromise.Result(), connectionID, config.Metrics, config.Logger)
if err != nil {
// RegisterTunnel RPC failure
return clientRegisterTunnelError{cause: err}
}
for _, logLine := range registration.LogLines {
config.Logger.Info(logLine)
}
if regErr := processRegisterTunnelError(registration.Err, registration.PermanentFailure, config.Metrics); regErr != nil {
return regErr
}
if registration.TunnelID != "" {
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config.Metrics.tunnelsHA.AddTunnelID(connectionID, registration.TunnelID)
config.Logger.Infof("Each HA connection's tunnel IDs: %v", config.Metrics.tunnelsHA.String())
}
// Print out the user's trial zone URL in a nice box (if they requested and got one)
if isTrialTunnel := config.Hostname == ""; isTrialTunnel {
if url, err := url.Parse(registration.Url); err == nil {
for _, line := range asciiBox(trialZoneMsg(url.String()), 2) {
config.Logger.Infoln(line)
}
} else {
config.Logger.Errorln("Failed to connect tunnel, please try again.")
return fmt.Errorf("empty URL in response from Cloudflare edge")
}
}
config.Logger.Infof("Route propagating, it may take up to 1 minute for your new route to become functional")
return nil
}
func processRegisterTunnelError(err string, permanentFailure bool, metrics *TunnelMetrics) error {
if err == "" {
metrics.regSuccess.Inc()
return nil
}
metrics.regFail.WithLabelValues(err).Inc()
if err == DuplicateConnectionError {
return dupConnRegisterTunnelError{}
}
return serverRegisterTunnelError{
cause: fmt.Errorf("Server error: %s", err),
permanent: permanentFailure,
}
}
func UnregisterTunnel(muxer *h2mux.Muxer, gracePeriod time.Duration, logger *log.Logger) error {
logger.Debug("initiating RPC stream to unregister")
stream, err := muxer.OpenStream([]h2mux.Header{
{Name: ":method", Value: "RPC"},
{Name: ":scheme", Value: "capnp"},
{Name: ":path", Value: "*"},
}, nil)
if err != nil {
// RPC stream open error
return err
}
if !IsRPCStreamResponse(stream.Headers) {
// stream response error
return err
}
ctx := context.Background()
conn := rpc.NewConn(
tunnelrpc.NewTransportLogger(logger.WithField("subsystem", "rpc-unregister"), rpc.StreamTransport(stream)),
tunnelrpc.ConnLog(logger.WithField("subsystem", "rpc-transport")),
)
defer conn.Close()
ts := tunnelpogs.TunnelServer_PogsClient{Client: conn.Bootstrap(ctx)}
// gracePeriod is encoded in int64 using capnproto
return ts.UnregisterTunnel(ctx, gracePeriod.Nanoseconds())
}
func LogServerInfo(
promise tunnelrpc.ServerInfo_Promise,
connectionID uint8,
metrics *TunnelMetrics,
logger *log.Logger,
) {
serverInfoMessage, err := promise.Struct()
if err != nil {
logger.WithError(err).Warn("Failed to retrieve server information")
return
}
serverInfo, err := tunnelpogs.UnmarshalServerInfo(serverInfoMessage)
if err != nil {
logger.WithError(err).Warn("Failed to retrieve server information")
return
}
logger.Infof("Connected to %s", serverInfo.LocationName)
metrics.registerServerLocation(uint8ToString(connectionID), serverInfo.LocationName)
}
func H2RequestHeadersToH1Request(h2 []h2mux.Header, h1 *http.Request) error {
for _, header := range h2 {
switch header.Name {
case ":method":
h1.Method = header.Value
case ":scheme":
case ":authority":
// Otherwise the host header will be based on the origin URL
h1.Host = header.Value
case ":path":
u, err := url.Parse(header.Value)
if err != nil {
return fmt.Errorf("unparseable path")
}
resolved := h1.URL.ResolveReference(u)
// prevent escaping base URL
if !strings.HasPrefix(resolved.String(), h1.URL.String()) {
return fmt.Errorf("invalid path")
}
h1.URL = resolved
case "content-length":
contentLength, err := strconv.ParseInt(header.Value, 10, 64)
if err != nil {
return fmt.Errorf("unparseable content length")
}
h1.ContentLength = contentLength
default:
h1.Header.Add(http.CanonicalHeaderKey(header.Name), header.Value)
}
}
return nil
}
func H1ResponseToH2Response(h1 *http.Response) (h2 []h2mux.Header) {
h2 = []h2mux.Header{{Name: ":status", Value: fmt.Sprintf("%d", h1.StatusCode)}}
for headerName, headerValues := range h1.Header {
for _, headerValue := range headerValues {
h2 = append(h2, h2mux.Header{Name: strings.ToLower(headerName), Value: headerValue})
}
}
return
}
func FindCfRayHeader(h1 *http.Request) string {
return h1.Header.Get("Cf-Ray")
}
type TunnelHandler struct {
originUrl string
muxer *h2mux.Muxer
httpClient http.RoundTripper
tlsConfig *tls.Config
tags []tunnelpogs.Tag
metrics *TunnelMetrics
// connectionID is only used by metrics, and prometheus requires labels to be string
connectionID string
logger *log.Logger
noChunkedEncoding bool
}
var dialer = net.Dialer{DualStack: true}
// NewTunnelHandler returns a TunnelHandler, origin LAN IP and error
func NewTunnelHandler(ctx context.Context,
config *TunnelConfig,
addr string,
connectionID uint8,
) (*TunnelHandler, string, error) {
originURL, err := validation.ValidateUrl(config.OriginUrl)
if err != nil {
return nil, "", fmt.Errorf("unable to parse origin URL %#v", originURL)
}
h := &TunnelHandler{
originUrl: originURL,
httpClient: config.HTTPTransport,
tlsConfig: config.ClientTlsConfig,
tags: config.Tags,
metrics: config.Metrics,
connectionID: uint8ToString(connectionID),
logger: config.Logger,
noChunkedEncoding: config.NoChunkedEncoding,
}
if h.httpClient == nil {
h.httpClient = http.DefaultTransport
}
// Inherit from parent context so we can cancel (Ctrl-C) while dialing
dialCtx, dialCancel := context.WithTimeout(ctx, dialTimeout)
// TUN-92: enforce a timeout on dial and handshake (as tls.Dial does not support one)
plaintextEdgeConn, err := dialer.DialContext(dialCtx, "tcp", addr)
dialCancel()
if err != nil {
return nil, "", dialError{cause: errors.Wrap(err, "DialContext error")}
}
edgeConn := tls.Client(plaintextEdgeConn, config.TlsConfig)
edgeConn.SetDeadline(time.Now().Add(dialTimeout))
err = edgeConn.Handshake()
if err != nil {
return nil, "", dialError{cause: errors.Wrap(err, "Handshake with edge error")}
}
// clear the deadline on the conn; h2mux has its own timeouts
edgeConn.SetDeadline(time.Time{})
// Establish a muxed connection with the edge
// Client mux handshake with agent server
h.muxer, err = h2mux.Handshake(edgeConn, edgeConn, h2mux.MuxerConfig{
Timeout: 5 * time.Second,
Handler: h,
IsClient: true,
HeartbeatInterval: config.HeartbeatInterval,
MaxHeartbeats: config.MaxHeartbeats,
Logger: config.TransportLogger.WithFields(log.Fields{}),
CompressionQuality: h2mux.CompressionSetting(config.CompressionQuality),
})
if err != nil {
return h, "", errors.New("TLS handshake error")
}
return h, edgeConn.LocalAddr().String(), err
}
func (h *TunnelHandler) AppendTagHeaders(r *http.Request) {
for _, tag := range h.tags {
r.Header.Add(TagHeaderNamePrefix+tag.Name, tag.Value)
}
}
func (h *TunnelHandler) ServeStream(stream *h2mux.MuxedStream) error {
h.metrics.incrementRequests(h.connectionID)
req, err := http.NewRequest("GET", h.originUrl, h2mux.MuxedStreamReader{MuxedStream: stream})
if err != nil {
h.logger.WithError(err).Panic("Unexpected error from http.NewRequest")
}
err = H2RequestHeadersToH1Request(stream.Headers, req)
if err != nil {
h.logger.WithError(err).Error("invalid request received")
}
h.AppendTagHeaders(req)
cfRay := FindCfRayHeader(req)
lbProbe := isLBProbeRequest(req)
h.logRequest(req, cfRay, lbProbe)
if websocket.IsWebSocketUpgrade(req) {
conn, response, err := websocket.ClientConnect(req, h.tlsConfig)
if err != nil {
h.logError(stream, err)
} else {
stream.WriteHeaders(H1ResponseToH2Response(response))
defer conn.Close()
// Copy to/from stream to the undelying connection. Use the underlying
// connection because cloudflared doesn't operate on the message themselves
websocket.Stream(conn.UnderlyingConn(), stream)
h.metrics.incrementResponses(h.connectionID, "200")
h.logResponse(response, cfRay, lbProbe)
}
} else {
// Support for WSGI Servers by switching transfer encoding from chunked to gzip/deflate
if h.noChunkedEncoding {
req.TransferEncoding = []string{"gzip", "deflate"}
cLength, err := strconv.Atoi(req.Header.Get("Content-Length"))
if err == nil {
req.ContentLength = int64(cLength)
}
}
// Request origin to keep connection alive to improve performance
req.Header.Set("Connection", "keep-alive")
response, err := h.httpClient.RoundTrip(req)
if err != nil {
h.logError(stream, err)
} else {
defer response.Body.Close()
stream.WriteHeaders(H1ResponseToH2Response(response))
if h.isEventStream(response) {
h.writeEventStream(stream, response.Body)
} else {
// Use CopyBuffer, because Copy only allocates a 32KiB buffer, and cross-stream
// compression generates dictionary on first write
io.CopyBuffer(stream, response.Body, make([]byte, 512*1024))
}
h.metrics.incrementResponses(h.connectionID, "200")
h.logResponse(response, cfRay, lbProbe)
}
}
h.metrics.decrementConcurrentRequests(h.connectionID)
return nil
}
func (h *TunnelHandler) writeEventStream(stream *h2mux.MuxedStream, responseBody io.ReadCloser) {
reader := bufio.NewReader(responseBody)
for {
line, err := reader.ReadBytes('\n')
if err != nil {
break
}
stream.Write(line)
}
}
func (h *TunnelHandler) isEventStream(response *http.Response) bool {
if response.Header.Get("content-type") == "text/event-stream" {
h.logger.Debug("Detected Server-Side Events from Origin")
return true
}
return false
}
func (h *TunnelHandler) logError(stream *h2mux.MuxedStream, err error) {
h.logger.WithError(err).Error("HTTP request error")
stream.WriteHeaders([]h2mux.Header{{Name: ":status", Value: "502"}})
stream.Write([]byte("502 Bad Gateway"))
h.metrics.incrementResponses(h.connectionID, "502")
}
func (h *TunnelHandler) logRequest(req *http.Request, cfRay string, lbProbe bool) {
logger := log.NewEntry(h.logger)
if cfRay != "" {
logger = logger.WithField("CF-RAY", cfRay)
logger.Debugf("%s %s %s", req.Method, req.URL, req.Proto)
} else if lbProbe {
logger.Debugf("Load Balancer health check %s %s %s", req.Method, req.URL, req.Proto)
} else {
logger.Warnf("All requests should have a CF-RAY header. Please open a support ticket with Cloudflare. %s %s %s ", req.Method, req.URL, req.Proto)
}
logger.Debugf("Request Headers %+v", req.Header)
if contentLen := req.ContentLength; contentLen == -1 {
logger.Debugf("Request Content length unknown")
} else {
logger.Debugf("Request content length %d", contentLen)
}
}
func (h *TunnelHandler) logResponse(r *http.Response, cfRay string, lbProbe bool) {
logger := log.NewEntry(h.logger)
if cfRay != "" {
logger = logger.WithField("CF-RAY", cfRay)
logger.Debugf("%s", r.Status)
} else if lbProbe {
logger.Debugf("Response to Load Balancer health check %s", r.Status)
} else {
logger.Infof("%s", r.Status)
}
logger.Debugf("Response Headers %+v", r.Header)
if contentLen := r.ContentLength; contentLen == -1 {
logger.Debugf("Response content length unknown")
} else {
logger.Debugf("Response content length %d", contentLen)
}
}
func (h *TunnelHandler) UpdateMetrics(connectionID string) {
h.metrics.updateMuxerMetrics(connectionID, h.muxer.Metrics())
}
func uint8ToString(input uint8) string {
return strconv.FormatUint(uint64(input), 10)
}
func isLBProbeRequest(req *http.Request) bool {
return strings.HasPrefix(req.UserAgent(), lbProbeUserAgentPrefix)
}
// Print out the given lines in a nice ASCII box.
func asciiBox(lines []string, padding int) (box []string) {
maxLen := maxLen(lines)
spacer := strings.Repeat(" ", padding)
border := "+" + strings.Repeat("-", maxLen+(padding*2)) + "+"
box = append(box, border)
for _, line := range lines {
box = append(box, "|"+spacer+line+strings.Repeat(" ", maxLen-len(line))+spacer+"|")
}
box = append(box, border)
return
}
func maxLen(lines []string) int {
max := 0
for _, line := range lines {
if len(line) > max {
max = len(line)
}
}
return max
}
func trialZoneMsg(url string) []string {
return []string{
"Your free tunnel has started! Visit it:",
" " + url,
}
}
func activeIncidentsMsg(incidents []Incident) string {
preamble := "There is an active Cloudflare incident that may be related:"
if len(incidents) > 1 {
preamble = "There are active Cloudflare incidents that may be related:"
}
incidentStrings := []string{}
for _, incident := range incidents {
incidentString := fmt.Sprintf("%s (%s)", incident.Name, incident.URL())
incidentStrings = append(incidentStrings, incidentString)
}
return preamble + " " + strings.Join(incidentStrings, "; ")
}