cloudflared-mirror/metrics/readiness.go

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package metrics
import (
"encoding/json"
"fmt"
"net/http"
"sync"
conn "github.com/cloudflare/cloudflared/connection"
"github.com/rs/zerolog"
)
// ReadyServer serves HTTP 200 if the tunnel can serve traffic. Intended for k8s readiness checks.
type ReadyServer struct {
sync.RWMutex
isConnected map[int]bool
log *zerolog.Logger
}
// NewReadyServer initializes a ReadyServer and starts listening for dis/connection events.
func NewReadyServer(log *zerolog.Logger) *ReadyServer {
return &ReadyServer{
isConnected: make(map[int]bool, 0),
log: log,
}
}
func (rs *ReadyServer) OnTunnelEvent(c conn.Event) {
switch c.EventType {
case conn.Connected:
rs.Lock()
rs.isConnected[int(c.Index)] = true
rs.Unlock()
case conn.Disconnected, conn.Reconnecting, conn.RegisteringTunnel, conn.Unregistering:
rs.Lock()
rs.isConnected[int(c.Index)] = false
rs.Unlock()
default:
rs.log.Error().Msgf("Unknown connection event case %v", c)
}
}
type body struct {
Status int `json:"status"`
ReadyConnections int `json:"readyConnections"`
}
// ServeHTTP responds with HTTP 200 if the tunnel is connected to the edge.
func (rs *ReadyServer) ServeHTTP(w http.ResponseWriter, r *http.Request) {
statusCode, readyConnections := rs.makeResponse()
w.WriteHeader(statusCode)
body := body{
Status: statusCode,
ReadyConnections: readyConnections,
}
msg, err := json.Marshal(body)
if err != nil {
_, _ = fmt.Fprintf(w, `{"error": "%s"}`, err)
}
_, _ = w.Write(msg)
}
// This is the bulk of the logic for ServeHTTP, broken into its own pure function
// to make unit testing easy.
func (rs *ReadyServer) makeResponse() (statusCode, readyConnections int) {
statusCode = http.StatusServiceUnavailable
rs.RLock()
defer rs.RUnlock()
for _, connected := range rs.isConnected {
if connected {
statusCode = http.StatusOK
readyConnections++
}
}
return statusCode, readyConnections
}