bf51655a7b
Signed-off-by: Jacek J. Łakis <jacek.lakis@intel.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
133 lines
3.6 KiB
Go
133 lines
3.6 KiB
Go
/*
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Copyright 2014 The Kubernetes Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package healthz
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import (
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"bytes"
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"fmt"
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"net/http"
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"sync"
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)
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// HealthzChecker is a named healthz checker.
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type HealthzChecker interface {
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Name() string
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Check(req *http.Request) error
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}
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var defaultHealthz = sync.Once{}
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// DefaultHealthz installs the default healthz check to the http.DefaultServeMux.
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func DefaultHealthz(checks ...HealthzChecker) {
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defaultHealthz.Do(func() {
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InstallHandler(http.DefaultServeMux, checks...)
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})
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}
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// PingHealthz returns true automatically when checked
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var PingHealthz HealthzChecker = ping{}
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// ping implements the simplest possible healthz checker.
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type ping struct{}
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func (ping) Name() string {
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return "ping"
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}
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// PingHealthz is a health check that returns true.
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func (ping) Check(_ *http.Request) error {
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return nil
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}
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// NamedCheck returns a healthz checker for the given name and function.
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func NamedCheck(name string, check func(r *http.Request) error) HealthzChecker {
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return &healthzCheck{name, check}
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}
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// InstallHandler registers a handler for health checking on the path "/healthz" to mux.
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func InstallHandler(mux mux, checks ...HealthzChecker) {
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if len(checks) == 0 {
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checks = []HealthzChecker{PingHealthz}
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}
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mux.Handle("/healthz", handleRootHealthz(checks...))
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for _, check := range checks {
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mux.Handle(fmt.Sprintf("/healthz/%v", check.Name()), adaptCheckToHandler(check.Check))
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}
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}
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// mux is an interface describing the methods InstallHandler requires.
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type mux interface {
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Handle(pattern string, handler http.Handler)
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}
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// healthzCheck implements HealthzChecker on an arbitrary name and check function.
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type healthzCheck struct {
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name string
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check func(r *http.Request) error
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}
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var _ HealthzChecker = &healthzCheck{}
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func (c *healthzCheck) Name() string {
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return c.name
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}
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func (c *healthzCheck) Check(r *http.Request) error {
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return c.check(r)
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}
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// handleRootHealthz returns an http.HandlerFunc that serves the provided checks.
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func handleRootHealthz(checks ...HealthzChecker) http.HandlerFunc {
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return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
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failed := false
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var verboseOut bytes.Buffer
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for _, check := range checks {
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err := check.Check(r)
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if err != nil {
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fmt.Fprintf(&verboseOut, "[-]%v failed: %v\n", check.Name(), err)
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failed = true
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} else {
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fmt.Fprintf(&verboseOut, "[+]%v ok\n", check.Name())
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}
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}
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// always be verbose on failure
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if failed {
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http.Error(w, fmt.Sprintf("%vhealthz check failed", verboseOut.String()), http.StatusInternalServerError)
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return
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}
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if _, found := r.URL.Query()["verbose"]; !found {
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fmt.Fprint(w, "ok")
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return
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}
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verboseOut.WriteTo(w)
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fmt.Fprint(w, "healthz check passed\n")
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})
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}
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// adaptCheckToHandler returns an http.HandlerFunc that serves the provided checks.
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func adaptCheckToHandler(c func(r *http.Request) error) http.HandlerFunc {
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return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
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err := c(r)
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if err != nil {
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http.Error(w, fmt.Sprintf("internal server error: %v", err), http.StatusInternalServerError)
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} else {
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fmt.Fprint(w, "ok")
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}
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})
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}
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