k3s/pkg/health/health_check.go

99 lines
3.0 KiB
Go

/*
Copyright 2014 Google Inc. All rights reserved.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
package health
import (
"fmt"
"net/http"
"strconv"
"github.com/GoogleCloudPlatform/kubernetes/pkg/api"
"github.com/golang/glog"
)
// HealthChecker defines an abstract interface for checking container health.
type HealthChecker interface {
HealthCheck(container api.Container) (Status, error)
}
// NewHealthChecker creates a new HealthChecker which supports multiple types of liveness probes.
func NewHealthChecker() HealthChecker {
return &MuxHealthChecker{
checkers: map[string]HealthChecker{
"http": &HTTPHealthChecker{
client: &http.Client{},
},
},
}
}
// MuxHealthChecker bundles multiple implementations of HealthChecker of different types.
type MuxHealthChecker struct {
checkers map[string]HealthChecker
}
// HealthCheck delegates the health-checking of the container to one of the bundled implementations.
// It chooses an implementation according to container.LivenessProbe.Type.
// If there is no matching health checker it returns Unknown, nil.
func (m *MuxHealthChecker) HealthCheck(container api.Container) (Status, error) {
checker, ok := m.checkers[container.LivenessProbe.Type]
if !ok || checker == nil {
glog.Warningf("Failed to find health checker for %s %s", container.Name, container.LivenessProbe.Type)
return Unknown, nil
}
return checker.HealthCheck(container)
}
// HTTPHealthChecker is an implementation of HealthChecker which checks container health by sending HTTP Get requests.
type HTTPHealthChecker struct {
client HTTPGetInterface
}
func (h *HTTPHealthChecker) findPort(container api.Container, portName string) int64 {
for _, port := range container.Ports {
if port.Name == portName {
// TODO This means you can only health check exposed ports
return int64(port.HostPort)
}
}
return -1
}
// HealthCheck checks if the container is healthy by trying sending HTTP Get requests to the container.
func (h *HTTPHealthChecker) HealthCheck(container api.Container) (Status, error) {
params := container.LivenessProbe.HTTPGet
if params == nil {
return Unknown, fmt.Errorf("Error, no HTTP parameters specified: %v", container)
}
port := h.findPort(container, params.Port)
if port == -1 {
var err error
port, err = strconv.ParseInt(params.Port, 10, 0)
if err != nil {
return Unknown, err
}
}
var host string
if len(params.Host) > 0 {
host = params.Host
} else {
host = "localhost"
}
url := fmt.Sprintf("http://%s:%d%s", host, port, params.Path)
return Check(url, h.client)
}