traefik/pkg/server/service/service.go
2024-03-12 12:08:03 +01:00

374 lines
12 KiB
Go

package service
import (
"context"
"encoding/hex"
"errors"
"fmt"
"hash/fnv"
"math/rand"
"net/http"
"net/http/httputil"
"net/url"
"reflect"
"strings"
"time"
"github.com/containous/alice"
"github.com/rs/zerolog/log"
"github.com/traefik/traefik/v3/pkg/config/dynamic"
"github.com/traefik/traefik/v3/pkg/config/runtime"
"github.com/traefik/traefik/v3/pkg/healthcheck"
"github.com/traefik/traefik/v3/pkg/logs"
"github.com/traefik/traefik/v3/pkg/middlewares/accesslog"
metricsMiddle "github.com/traefik/traefik/v3/pkg/middlewares/metrics"
"github.com/traefik/traefik/v3/pkg/middlewares/observability"
"github.com/traefik/traefik/v3/pkg/safe"
"github.com/traefik/traefik/v3/pkg/server/cookie"
"github.com/traefik/traefik/v3/pkg/server/middleware"
"github.com/traefik/traefik/v3/pkg/server/provider"
"github.com/traefik/traefik/v3/pkg/server/service/loadbalancer/failover"
"github.com/traefik/traefik/v3/pkg/server/service/loadbalancer/mirror"
"github.com/traefik/traefik/v3/pkg/server/service/loadbalancer/wrr"
)
const defaultMaxBodySize int64 = -1
// RoundTripperGetter is a roundtripper getter interface.
type RoundTripperGetter interface {
Get(name string) (http.RoundTripper, error)
}
// Manager The service manager.
type Manager struct {
routinePool *safe.Pool
observabilityMgr *middleware.ObservabilityMgr
bufferPool httputil.BufferPool
roundTripperManager RoundTripperGetter
services map[string]http.Handler
configs map[string]*runtime.ServiceInfo
healthCheckers map[string]*healthcheck.ServiceHealthChecker
rand *rand.Rand // For the initial shuffling of load-balancers.
}
// NewManager creates a new Manager.
func NewManager(configs map[string]*runtime.ServiceInfo, observabilityMgr *middleware.ObservabilityMgr, routinePool *safe.Pool, roundTripperManager RoundTripperGetter) *Manager {
return &Manager{
routinePool: routinePool,
observabilityMgr: observabilityMgr,
bufferPool: newBufferPool(),
roundTripperManager: roundTripperManager,
services: make(map[string]http.Handler),
configs: configs,
healthCheckers: make(map[string]*healthcheck.ServiceHealthChecker),
rand: rand.New(rand.NewSource(time.Now().UnixNano())),
}
}
// BuildHTTP Creates a http.Handler for a service configuration.
func (m *Manager) BuildHTTP(rootCtx context.Context, serviceName string) (http.Handler, error) {
serviceName = provider.GetQualifiedName(rootCtx, serviceName)
ctx := log.Ctx(rootCtx).With().Str(logs.ServiceName, serviceName).Logger().
WithContext(provider.AddInContext(rootCtx, serviceName))
handler, ok := m.services[serviceName]
if ok {
return handler, nil
}
conf, ok := m.configs[serviceName]
if !ok {
return nil, fmt.Errorf("the service %q does not exist", serviceName)
}
if conf.Status == runtime.StatusDisabled {
return nil, errors.New(strings.Join(conf.Err, ", "))
}
value := reflect.ValueOf(*conf.Service)
var count int
for i := range value.NumField() {
if !value.Field(i).IsNil() {
count++
}
}
if count > 1 {
err := errors.New("cannot create service: multi-types service not supported, consider declaring two different pieces of service instead")
conf.AddError(err, true)
return nil, err
}
var lb http.Handler
switch {
case conf.LoadBalancer != nil:
var err error
lb, err = m.getLoadBalancerServiceHandler(ctx, serviceName, conf)
if err != nil {
conf.AddError(err, true)
return nil, err
}
case conf.Weighted != nil:
var err error
lb, err = m.getWRRServiceHandler(ctx, serviceName, conf.Weighted)
if err != nil {
conf.AddError(err, true)
return nil, err
}
case conf.Mirroring != nil:
var err error
lb, err = m.getMirrorServiceHandler(ctx, conf.Mirroring)
if err != nil {
conf.AddError(err, true)
return nil, err
}
case conf.Failover != nil:
var err error
lb, err = m.getFailoverServiceHandler(ctx, serviceName, conf.Failover)
if err != nil {
conf.AddError(err, true)
return nil, err
}
default:
sErr := fmt.Errorf("the service %q does not have any type defined", serviceName)
conf.AddError(sErr, true)
return nil, sErr
}
m.services[serviceName] = lb
return lb, nil
}
func (m *Manager) getFailoverServiceHandler(ctx context.Context, serviceName string, config *dynamic.Failover) (http.Handler, error) {
f := failover.New(config.HealthCheck)
serviceHandler, err := m.BuildHTTP(ctx, config.Service)
if err != nil {
return nil, err
}
f.SetHandler(serviceHandler)
updater, ok := serviceHandler.(healthcheck.StatusUpdater)
if !ok {
return nil, fmt.Errorf("child service %v of %v not a healthcheck.StatusUpdater (%T)", config.Service, serviceName, serviceHandler)
}
if err := updater.RegisterStatusUpdater(func(up bool) {
f.SetHandlerStatus(ctx, up)
}); err != nil {
return nil, fmt.Errorf("cannot register %v as updater for %v: %w", config.Service, serviceName, err)
}
fallbackHandler, err := m.BuildHTTP(ctx, config.Fallback)
if err != nil {
return nil, err
}
f.SetFallbackHandler(fallbackHandler)
// Do not report the health of the fallback handler.
if config.HealthCheck == nil {
return f, nil
}
fallbackUpdater, ok := fallbackHandler.(healthcheck.StatusUpdater)
if !ok {
return nil, fmt.Errorf("child service %v of %v not a healthcheck.StatusUpdater (%T)", config.Fallback, serviceName, fallbackHandler)
}
if err := fallbackUpdater.RegisterStatusUpdater(func(up bool) {
f.SetFallbackHandlerStatus(ctx, up)
}); err != nil {
return nil, fmt.Errorf("cannot register %v as updater for %v: %w", config.Fallback, serviceName, err)
}
return f, nil
}
func (m *Manager) getMirrorServiceHandler(ctx context.Context, config *dynamic.Mirroring) (http.Handler, error) {
serviceHandler, err := m.BuildHTTP(ctx, config.Service)
if err != nil {
return nil, err
}
maxBodySize := defaultMaxBodySize
if config.MaxBodySize != nil {
maxBodySize = *config.MaxBodySize
}
handler := mirror.New(serviceHandler, m.routinePool, maxBodySize, config.HealthCheck)
for _, mirrorConfig := range config.Mirrors {
mirrorHandler, err := m.BuildHTTP(ctx, mirrorConfig.Name)
if err != nil {
return nil, err
}
err = handler.AddMirror(mirrorHandler, mirrorConfig.Percent)
if err != nil {
return nil, err
}
}
return handler, nil
}
func (m *Manager) getWRRServiceHandler(ctx context.Context, serviceName string, config *dynamic.WeightedRoundRobin) (http.Handler, error) {
// TODO Handle accesslog and metrics with multiple service name
if config.Sticky != nil && config.Sticky.Cookie != nil {
config.Sticky.Cookie.Name = cookie.GetName(config.Sticky.Cookie.Name, serviceName)
}
balancer := wrr.New(config.Sticky, config.HealthCheck != nil)
for _, service := range shuffle(config.Services, m.rand) {
serviceHandler, err := m.BuildHTTP(ctx, service.Name)
if err != nil {
return nil, err
}
balancer.Add(service.Name, serviceHandler, service.Weight)
if config.HealthCheck == nil {
continue
}
childName := service.Name
updater, ok := serviceHandler.(healthcheck.StatusUpdater)
if !ok {
return nil, fmt.Errorf("child service %v of %v not a healthcheck.StatusUpdater (%T)", childName, serviceName, serviceHandler)
}
if err := updater.RegisterStatusUpdater(func(up bool) {
balancer.SetStatus(ctx, childName, up)
}); err != nil {
return nil, fmt.Errorf("cannot register %v as updater for %v: %w", childName, serviceName, err)
}
log.Ctx(ctx).Debug().Str("parent", serviceName).Str("child", childName).
Msg("Child service will update parent on status change")
}
return balancer, nil
}
func (m *Manager) getLoadBalancerServiceHandler(ctx context.Context, serviceName string, info *runtime.ServiceInfo) (http.Handler, error) {
service := info.LoadBalancer
logger := log.Ctx(ctx)
logger.Debug().Msg("Creating load-balancer")
// TODO: should we keep this config value as Go is now handling stream response correctly?
flushInterval := dynamic.DefaultFlushInterval
if service.ResponseForwarding != nil {
flushInterval = service.ResponseForwarding.FlushInterval
}
if len(service.ServersTransport) > 0 {
service.ServersTransport = provider.GetQualifiedName(ctx, service.ServersTransport)
}
if service.Sticky != nil && service.Sticky.Cookie != nil {
service.Sticky.Cookie.Name = cookie.GetName(service.Sticky.Cookie.Name, serviceName)
}
// We make sure that the PassHostHeader value is defined to avoid panics.
passHostHeader := dynamic.DefaultPassHostHeader
if service.PassHostHeader != nil {
passHostHeader = *service.PassHostHeader
}
roundTripper, err := m.roundTripperManager.Get(service.ServersTransport)
if err != nil {
return nil, err
}
lb := wrr.New(service.Sticky, service.HealthCheck != nil)
healthCheckTargets := make(map[string]*url.URL)
for _, server := range shuffle(service.Servers, m.rand) {
hasher := fnv.New64a()
_, _ = hasher.Write([]byte(server.URL)) // this will never return an error.
proxyName := hex.EncodeToString(hasher.Sum(nil))
target, err := url.Parse(server.URL)
if err != nil {
return nil, fmt.Errorf("error parsing server URL %s: %w", server.URL, err)
}
logger.Debug().Str(logs.ServerName, proxyName).Stringer("target", target).
Msg("Creating server")
qualifiedSvcName := provider.GetQualifiedName(ctx, serviceName)
if m.observabilityMgr.ShouldAddTracing(qualifiedSvcName) || m.observabilityMgr.ShouldAddMetrics(qualifiedSvcName) {
// Wrapping the roundTripper with the Tracing roundTripper,
// to handle the reverseProxy client span creation.
roundTripper = newObservabilityRoundTripper(m.observabilityMgr.SemConvMetricsRegistry(), roundTripper)
}
proxy := buildSingleHostProxy(target, passHostHeader, time.Duration(flushInterval), roundTripper, m.bufferPool)
// Prevents from enabling observability for internal resources.
if m.observabilityMgr.ShouldAddAccessLogs(qualifiedSvcName) {
proxy = accesslog.NewFieldHandler(proxy, accesslog.ServiceURL, target.String(), nil)
proxy = accesslog.NewFieldHandler(proxy, accesslog.ServiceAddr, target.Host, nil)
proxy = accesslog.NewFieldHandler(proxy, accesslog.ServiceName, serviceName, accesslog.AddServiceFields)
}
if m.observabilityMgr.MetricsRegistry() != nil && m.observabilityMgr.MetricsRegistry().IsSvcEnabled() &&
m.observabilityMgr.ShouldAddMetrics(qualifiedSvcName) {
metricsHandler := metricsMiddle.WrapServiceHandler(ctx, m.observabilityMgr.MetricsRegistry(), serviceName)
proxy, err = alice.New().
Append(observability.WrapMiddleware(ctx, metricsHandler)).
Then(proxy)
if err != nil {
return nil, fmt.Errorf("error wrapping metrics handler: %w", err)
}
}
if m.observabilityMgr.ShouldAddTracing(qualifiedSvcName) {
proxy = observability.NewService(ctx, serviceName, proxy)
}
lb.Add(proxyName, proxy, server.Weight)
// servers are considered UP by default.
info.UpdateServerStatus(target.String(), runtime.StatusUp)
healthCheckTargets[proxyName] = target
}
if service.HealthCheck != nil {
m.healthCheckers[serviceName] = healthcheck.NewServiceHealthChecker(
ctx,
m.observabilityMgr.MetricsRegistry(),
service.HealthCheck,
lb,
info,
roundTripper,
healthCheckTargets,
)
}
return lb, nil
}
// LaunchHealthCheck launches the health checks.
func (m *Manager) LaunchHealthCheck(ctx context.Context) {
for serviceName, hc := range m.healthCheckers {
logger := log.Ctx(ctx).With().Str(logs.ServiceName, serviceName).Logger()
go hc.Launch(logger.WithContext(ctx))
}
}
func shuffle[T any](values []T, r *rand.Rand) []T {
shuffled := make([]T, len(values))
copy(shuffled, values)
r.Shuffle(len(shuffled), func(i, j int) { shuffled[i], shuffled[j] = shuffled[j], shuffled[i] })
return shuffled
}