104 lines
3.0 KiB
Go
104 lines
3.0 KiB
Go
// Copyright 2020 by the contributors.
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//
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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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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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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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package healthcheck
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import (
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"encoding/json"
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"net/http"
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"sync"
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)
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// basicHandler is a basic Handler implementation.
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type basicHandler struct {
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http.ServeMux
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checksMutex sync.RWMutex
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livenessChecks map[string]Check
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readinessChecks map[string]Check
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}
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// NewHandler creates a new basic Handler
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func NewHandler() Handler {
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h := &basicHandler{
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livenessChecks: make(map[string]Check),
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readinessChecks: make(map[string]Check),
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}
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h.Handle("/live", http.HandlerFunc(h.LiveEndpoint))
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h.Handle("/ready", http.HandlerFunc(h.ReadyEndpoint))
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return h
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}
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func (s *basicHandler) LiveEndpoint(w http.ResponseWriter, r *http.Request) {
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s.handle(w, r, s.livenessChecks)
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}
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func (s *basicHandler) ReadyEndpoint(w http.ResponseWriter, r *http.Request) {
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s.handle(w, r, s.readinessChecks, s.livenessChecks)
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}
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func (s *basicHandler) AddLivenessCheck(name string, check Check) {
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s.checksMutex.Lock()
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defer s.checksMutex.Unlock()
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s.livenessChecks[name] = check
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}
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func (s *basicHandler) AddReadinessCheck(name string, check Check) {
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s.checksMutex.Lock()
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defer s.checksMutex.Unlock()
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s.readinessChecks[name] = check
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}
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func (s *basicHandler) collectChecks(checks map[string]Check, resultsOut map[string]string, statusOut *int) {
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s.checksMutex.RLock()
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defer s.checksMutex.RUnlock()
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for name, check := range checks {
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if err := check(); err != nil {
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*statusOut = http.StatusServiceUnavailable
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resultsOut[name] = err.Error()
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} else {
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resultsOut[name] = "OK"
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}
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}
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}
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func (s *basicHandler) handle(w http.ResponseWriter, r *http.Request, checks ...map[string]Check) {
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if r.Method != http.MethodGet {
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http.Error(w, "method not allowed", http.StatusMethodNotAllowed)
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return
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}
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checkResults := make(map[string]string)
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status := http.StatusOK
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for _, checks := range checks {
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s.collectChecks(checks, checkResults, &status)
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}
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// write out the response code and content type header
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w.Header().Set("Content-Type", "application/json; charset=utf-8")
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w.WriteHeader(status)
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// if ?hide=1, return an empty body. Kubernetes only cares about the
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// HTTP status code, so we won't waste bytes on the full body.
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if r.URL.Query().Get("hide") == "1" {
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_, _ = w.Write([]byte("{}\n"))
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return
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}
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// otherwise, write the JSON body ignoring any encoding errors (which
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// shouldn't really be possible since we're encoding a map[string]string).
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encoder := json.NewEncoder(w)
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encoder.SetIndent("", " ")
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_ = encoder.Encode(checkResults)
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}
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