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https://github.com/optim-enterprises-bv/kubernetes.git
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015bc3b7bd
It currently is impossible to use two healthz handlers on different ports in the same process. This removes the global variables in favor of requiring the consumer to specify all health checks up front.
129 lines
3.5 KiB
Go
129 lines
3.5 KiB
Go
/*
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Copyright 2014 Google Inc. All rights reserved.
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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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)
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// HealthzChecker is a named healthz check.
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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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// DefaultHealthz installs the default healthz check to the http.DefaultServeMux.
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func DefaultHealthz(checks ...HealthzChecker) {
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InstallHandler(http.DefaultServeMux, checks...)
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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 health 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 health 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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