traefik/server/service/service.go

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2018-11-14 09:18:03 +00:00
package service
import (
"context"
"fmt"
"net"
"net/http"
"net/http/httputil"
"net/url"
"time"
"github.com/containous/flaeg/parse"
"github.com/containous/traefik/config"
"github.com/containous/traefik/healthcheck"
"github.com/containous/traefik/log"
"github.com/containous/traefik/middlewares/emptybackendhandler"
"github.com/containous/traefik/old/middlewares/pipelining"
"github.com/containous/traefik/server/cookie"
"github.com/vulcand/oxy/forward"
"github.com/vulcand/oxy/roundrobin"
)
const (
defaultHealthCheckInterval = 30 * time.Second
defaultHealthCheckTimeout = 5 * time.Second
)
// See oxy/roundrobin/rr.go
type balancerHandler interface {
Servers() []*url.URL
ServeHTTP(w http.ResponseWriter, req *http.Request)
ServerWeight(u *url.URL) (int, bool)
RemoveServer(u *url.URL) error
UpsertServer(u *url.URL, options ...roundrobin.ServerOption) error
NextServer() (*url.URL, error)
Next() http.Handler
}
// NewManager creates a new Manager
func NewManager(configs map[string]*config.Service, defaultRoundTripper http.RoundTripper) *Manager {
return &Manager{
bufferPool: newBufferPool(),
defaultRoundTripper: defaultRoundTripper,
balancers: make(map[string][]healthcheck.BalancerHandler),
configs: configs,
}
}
// Manager The service manager
type Manager struct {
bufferPool httputil.BufferPool
defaultRoundTripper http.RoundTripper
balancers map[string][]healthcheck.BalancerHandler
configs map[string]*config.Service
}
// Build Creates a http.Handler for a service configuration.
func (m *Manager) Build(rootCtx context.Context, serviceName string, responseModifier func(*http.Response) error) (http.Handler, error) {
ctx := log.With(rootCtx, log.Str(log.ServiceName, serviceName))
// TODO refactor ?
if conf, ok := m.configs[serviceName]; ok {
// FIXME Should handle multiple service types
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if conf.LoadBalancer != nil {
return m.getLoadBalancerServiceHandler(ctx, serviceName, conf.LoadBalancer, responseModifier)
}
return nil, fmt.Errorf("the service %q doesn't have any load balancer", serviceName)
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}
return nil, fmt.Errorf("the service %q does not exits", serviceName)
}
func (m *Manager) getLoadBalancerServiceHandler(
ctx context.Context,
serviceName string,
service *config.LoadBalancerService,
responseModifier func(*http.Response) error,
) (http.Handler, error) {
fwd, err := m.buildForwarder(service.PassHostHeader, service.ResponseForwarding, responseModifier)
if err != nil {
return nil, err
}
fwd = pipelining.NewPipelining(fwd)
rr, err := roundrobin.New(fwd)
if err != nil {
return nil, err
}
balancer, err := m.getLoadBalancer(ctx, serviceName, service, fwd, rr)
if err != nil {
return nil, err
}
// TODO rename and checks
m.balancers[serviceName] = append(m.balancers[serviceName], balancer)
// Empty (backend with no servers)
return emptybackendhandler.New(balancer), nil
}
// LaunchHealthCheck Launches the health checks.
func (m *Manager) LaunchHealthCheck() {
backendConfigs := make(map[string]*healthcheck.BackendConfig)
for serviceName, balancers := range m.balancers {
ctx := log.With(context.Background(), log.Str(log.ServiceName, serviceName))
// FIXME aggregate
balancer := balancers[0]
// FIXME Should all the services handle healthcheck? Handle different types
service := m.configs[serviceName].LoadBalancer
// Health Check
var backendHealthCheck *healthcheck.BackendConfig
if hcOpts := buildHealthCheckOptions(ctx, balancer, serviceName, service.HealthCheck); hcOpts != nil {
log.FromContext(ctx).Debugf("Setting up healthcheck for service %s with %s", serviceName, *hcOpts)
hcOpts.Transport = m.defaultRoundTripper
backendHealthCheck = healthcheck.NewBackendConfig(*hcOpts, serviceName)
}
if backendHealthCheck != nil {
backendConfigs[serviceName] = backendHealthCheck
}
}
// FIXME metrics and context
healthcheck.GetHealthCheck().SetBackendsConfiguration(context.TODO(), backendConfigs)
}
func buildHealthCheckOptions(ctx context.Context, lb healthcheck.BalancerHandler, backend string, hc *config.HealthCheck) *healthcheck.Options {
if hc == nil || hc.Path == "" {
return nil
}
logger := log.FromContext(ctx)
interval := defaultHealthCheckInterval
if hc.Interval != "" {
intervalOverride, err := time.ParseDuration(hc.Interval)
if err != nil {
logger.Errorf("Illegal health check interval for '%s': %s", backend, err)
} else if intervalOverride <= 0 {
logger.Errorf("Health check interval smaller than zero for service '%s'", backend)
} else {
interval = intervalOverride
}
}
timeout := defaultHealthCheckTimeout
if hc.Timeout != "" {
timeoutOverride, err := time.ParseDuration(hc.Timeout)
if err != nil {
logger.Errorf("Illegal health check timeout for backend '%s': %s", backend, err)
} else if timeoutOverride <= 0 {
logger.Errorf("Health check timeout smaller than zero for backend '%s', backend", backend)
} else {
timeout = timeoutOverride
}
}
if timeout >= interval {
logger.Warnf("Health check timeout for backend '%s' should be lower than the health check interval. Interval set to timeout + 1 second (%s).", backend)
}
return &healthcheck.Options{
Scheme: hc.Scheme,
Path: hc.Path,
Port: hc.Port,
Interval: interval,
Timeout: timeout,
LB: lb,
Hostname: hc.Hostname,
Headers: hc.Headers,
}
}
func (m *Manager) getLoadBalancer(ctx context.Context, serviceName string, service *config.LoadBalancerService, fwd http.Handler, rr balancerHandler) (healthcheck.BalancerHandler, error) {
logger := log.FromContext(ctx)
var stickySession *roundrobin.StickySession
var cookieName string
if stickiness := service.Stickiness; stickiness != nil {
cookieName = cookie.GetName(stickiness.CookieName, serviceName)
stickySession = roundrobin.NewStickySession(cookieName)
}
var lb healthcheck.BalancerHandler
var err error
if service.Method == "drr" {
logger.Debug("Creating drr load-balancer")
if stickySession != nil {
logger.Debugf("Sticky session cookie name: %v", cookieName)
lb, err = roundrobin.NewRebalancer(rr, roundrobin.RebalancerStickySession(stickySession))
if err != nil {
return nil, err
}
} else {
lb, err = roundrobin.NewRebalancer(rr)
if err != nil {
return nil, err
}
}
} else {
if service.Method != "wrr" {
logger.Warnf("Invalid load-balancing method %q, fallback to 'wrr' method", service.Method)
}
logger.Debug("Creating wrr load-balancer")
if stickySession != nil {
logger.Debugf("Sticky session cookie name: %v", cookieName)
lb, err = roundrobin.New(fwd, roundrobin.EnableStickySession(stickySession))
if err != nil {
return nil, err
}
} else {
lb = rr
}
}
if err := m.upsertServers(ctx, lb, service.Servers); err != nil {
return nil, fmt.Errorf("error configuring load balancer for service %s: %v", serviceName, err)
}
return lb, nil
}
func (m *Manager) upsertServers(ctx context.Context, lb healthcheck.BalancerHandler, servers []config.Server) error {
logger := log.FromContext(ctx)
for name, srv := range servers {
u, err := url.Parse(srv.URL)
if err != nil {
return fmt.Errorf("error parsing server URL %s: %v", srv.URL, err)
}
logger.WithField(log.ServerName, name).Debugf("Creating server %d at %s with weight %d", name, u, srv.Weight)
if err := lb.UpsertServer(u, roundrobin.Weight(srv.Weight)); err != nil {
return fmt.Errorf("error adding server %s to load balancer: %v", srv.URL, err)
}
// FIXME Handle Metrics
}
return nil
}
func (m *Manager) buildForwarder(passHostHeader bool, responseForwarding *config.ResponseForwarding, responseModifier func(*http.Response) error) (http.Handler, error) {
var flushInterval parse.Duration
if responseForwarding != nil {
err := flushInterval.Set(responseForwarding.FlushInterval)
if err != nil {
return nil, fmt.Errorf("error creating flush interval: %v", err)
}
}
return forward.New(
forward.Stream(true),
forward.PassHostHeader(passHostHeader),
forward.RoundTripper(m.defaultRoundTripper),
forward.ResponseModifier(responseModifier),
forward.BufferPool(m.bufferPool),
forward.StreamingFlushInterval(time.Duration(flushInterval)),
forward.WebsocketConnectionClosedHook(func(req *http.Request, conn net.Conn) {
server := req.Context().Value(http.ServerContextKey).(*http.Server)
if server != nil {
connState := server.ConnState
if connState != nil {
connState(conn, http.StateClosed)
}
}
}),
)
}