traefik/pkg/healthcheck/healthcheck.go
mpl f6df556eb0 API: expose runtime representation
Co-authored-by: Julien Salleyron <julien.salleyron@gmail.com>
Co-authored-by: Jean-Baptiste Doumenjou <jb.doumenjou@gmail.com>
2019-05-16 10:58:06 +02:00

264 lines
7.5 KiB
Go

package healthcheck
import (
"context"
"fmt"
"net"
"net/http"
"net/url"
"strconv"
"sync"
"time"
"github.com/containous/traefik/pkg/config"
"github.com/containous/traefik/pkg/log"
"github.com/containous/traefik/pkg/safe"
"github.com/go-kit/kit/metrics"
"github.com/vulcand/oxy/roundrobin"
)
const (
serverUp = "UP"
serverDown = "DOWN"
)
var singleton *HealthCheck
var once sync.Once
// BalancerHandler includes functionality for load-balancing management.
type BalancerHandler interface {
ServeHTTP(w http.ResponseWriter, req *http.Request)
Servers() []*url.URL
RemoveServer(u *url.URL) error
UpsertServer(u *url.URL, options ...roundrobin.ServerOption) error
}
// metricsRegistry is a local interface in the health check package, exposing only the required metrics
// necessary for the health check package. This makes it easier for the tests.
type metricsRegistry interface {
BackendServerUpGauge() metrics.Gauge
}
// Options are the public health check options.
type Options struct {
Headers map[string]string
Hostname string
Scheme string
Path string
Port int
Transport http.RoundTripper
Interval time.Duration
Timeout time.Duration
LB BalancerHandler
}
func (opt Options) String() string {
return fmt.Sprintf("[Hostname: %s Headers: %v Path: %s Port: %d Interval: %s Timeout: %s]", opt.Hostname, opt.Headers, opt.Path, opt.Port, opt.Interval, opt.Timeout)
}
// BackendConfig HealthCheck configuration for a backend
type BackendConfig struct {
Options
name string
disabledURLs []*url.URL
}
func (b *BackendConfig) newRequest(serverURL *url.URL) (*http.Request, error) {
u, err := serverURL.Parse(b.Path)
if err != nil {
return nil, err
}
if len(b.Scheme) > 0 {
u.Scheme = b.Scheme
}
if b.Port != 0 {
u.Host = net.JoinHostPort(u.Hostname(), strconv.Itoa(b.Port))
}
return http.NewRequest(http.MethodGet, u.String(), http.NoBody)
}
// this function adds additional http headers and hostname to http.request
func (b *BackendConfig) addHeadersAndHost(req *http.Request) *http.Request {
if b.Options.Hostname != "" {
req.Host = b.Options.Hostname
}
for k, v := range b.Options.Headers {
req.Header.Set(k, v)
}
return req
}
// HealthCheck struct
type HealthCheck struct {
Backends map[string]*BackendConfig
metrics metricsRegistry
cancel context.CancelFunc
}
// SetBackendsConfiguration set backends configuration
func (hc *HealthCheck) SetBackendsConfiguration(parentCtx context.Context, backends map[string]*BackendConfig) {
hc.Backends = backends
if hc.cancel != nil {
hc.cancel()
}
ctx, cancel := context.WithCancel(parentCtx)
hc.cancel = cancel
for _, backend := range backends {
currentBackend := backend
safe.Go(func() {
hc.execute(ctx, currentBackend)
})
}
}
func (hc *HealthCheck) execute(ctx context.Context, backend *BackendConfig) {
log.Debugf("Initial health check for backend: %q", backend.name)
hc.checkBackend(backend)
ticker := time.NewTicker(backend.Interval)
defer ticker.Stop()
for {
select {
case <-ctx.Done():
log.Debugf("Stopping current health check goroutines of backend: %s", backend.name)
return
case <-ticker.C:
log.Debugf("Refreshing health check for backend: %s", backend.name)
hc.checkBackend(backend)
}
}
}
func (hc *HealthCheck) checkBackend(backend *BackendConfig) {
enabledURLs := backend.LB.Servers()
var newDisabledURLs []*url.URL
// FIXME re enable metrics
for _, disableURL := range backend.disabledURLs {
// FIXME serverUpMetricValue := float64(0)
if err := checkHealth(disableURL, backend); err == nil {
log.Warnf("Health check up: Returning to server list. Backend: %q URL: %q", backend.name, disableURL.String())
if err = backend.LB.UpsertServer(disableURL, roundrobin.Weight(1)); err != nil {
log.Error(err)
}
// FIXME serverUpMetricValue = 1
} else {
log.Warnf("Health check still failing. Backend: %q URL: %q Reason: %s", backend.name, disableURL.String(), err)
newDisabledURLs = append(newDisabledURLs, disableURL)
}
// FIXME labelValues := []string{"backend", backend.name, "url", disableURL.String()}
// FIXME hc.metrics.BackendServerUpGauge().With(labelValues...).Set(serverUpMetricValue)
}
backend.disabledURLs = newDisabledURLs
// FIXME re enable metrics
for _, enableURL := range enabledURLs {
// FIXME serverUpMetricValue := float64(1)
if err := checkHealth(enableURL, backend); err != nil {
log.Warnf("Health check failed: Remove from server list. Backend: %q URL: %q Reason: %s", backend.name, enableURL.String(), err)
if err := backend.LB.RemoveServer(enableURL); err != nil {
log.Error(err)
}
backend.disabledURLs = append(backend.disabledURLs, enableURL)
// FIXME serverUpMetricValue = 0
}
// FIXME labelValues := []string{"backend", backend.name, "url", enableURL.String()}
// FIXME hc.metrics.BackendServerUpGauge().With(labelValues...).Set(serverUpMetricValue)
}
}
// FIXME re add metrics
//func GetHealthCheck(metrics metricsRegistry) *HealthCheck {
// GetHealthCheck returns the health check which is guaranteed to be a singleton.
func GetHealthCheck() *HealthCheck {
once.Do(func() {
singleton = newHealthCheck()
//singleton = newHealthCheck(metrics)
})
return singleton
}
// FIXME re add metrics
//func newHealthCheck(metrics metricsRegistry) *HealthCheck {
func newHealthCheck() *HealthCheck {
return &HealthCheck{
Backends: make(map[string]*BackendConfig),
//metrics: metrics,
}
}
// NewBackendConfig Instantiate a new BackendConfig
func NewBackendConfig(options Options, backendName string) *BackendConfig {
return &BackendConfig{
Options: options,
name: backendName,
}
}
// checkHealth returns a nil error in case it was successful and otherwise
// a non-nil error with a meaningful description why the health check failed.
func checkHealth(serverURL *url.URL, backend *BackendConfig) error {
req, err := backend.newRequest(serverURL)
if err != nil {
return fmt.Errorf("failed to create HTTP request: %s", err)
}
req = backend.addHeadersAndHost(req)
client := http.Client{
Timeout: backend.Options.Timeout,
Transport: backend.Options.Transport,
}
resp, err := client.Do(req)
if err != nil {
return fmt.Errorf("HTTP request failed: %s", err)
}
defer resp.Body.Close()
if resp.StatusCode < http.StatusOK || resp.StatusCode >= http.StatusBadRequest {
return fmt.Errorf("received error status code: %v", resp.StatusCode)
}
return nil
}
// NewLBStatusUpdater returns a new LbStatusUpdater
func NewLBStatusUpdater(bh BalancerHandler, svinfo *config.ServiceInfo) *LbStatusUpdater {
return &LbStatusUpdater{
BalancerHandler: bh,
serviceInfo: svinfo,
}
}
// LbStatusUpdater wraps a BalancerHandler and a ServiceInfo,
// so it can keep track of the status of a server in the ServiceInfo.
type LbStatusUpdater struct {
BalancerHandler
serviceInfo *config.ServiceInfo // can be nil
}
// RemoveServer removes the given server from the BalancerHandler,
// and updates the status of the server to "DOWN".
func (lb *LbStatusUpdater) RemoveServer(u *url.URL) error {
err := lb.BalancerHandler.RemoveServer(u)
if err == nil && lb.serviceInfo != nil {
lb.serviceInfo.UpdateStatus(u.String(), serverDown)
}
return err
}
// UpsertServer adds the given server to the BalancerHandler,
// and updates the status of the server to "UP".
func (lb *LbStatusUpdater) UpsertServer(u *url.URL, options ...roundrobin.ServerOption) error {
err := lb.BalancerHandler.UpsertServer(u, options...)
if err == nil && lb.serviceInfo != nil {
lb.serviceInfo.UpdateStatus(u.String(), serverUp)
}
return err
}