84 lines
1.4 KiB
Go
84 lines
1.4 KiB
Go
// Package health implements an HTTP handler that responds to health checks.
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package health
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import (
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"context"
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"io"
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"net"
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"net/http"
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"time"
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clog "github.com/coredns/coredns/plugin/pkg/log"
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"github.com/coredns/coredns/plugin/pkg/reuseport"
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)
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var log = clog.NewWithPlugin("health")
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// Health implements healthchecks by exporting a HTTP endpoint.
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type health struct {
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Addr string
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lameduck time.Duration
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ln net.Listener
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nlSetup bool
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mux *http.ServeMux
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stop context.CancelFunc
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}
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func (h *health) OnStartup() error {
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if h.Addr == "" {
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h.Addr = ":8080"
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}
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ln, err := reuseport.Listen("tcp", h.Addr)
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if err != nil {
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return err
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}
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h.ln = ln
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h.mux = http.NewServeMux()
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h.nlSetup = true
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h.mux.HandleFunc("/health", func(w http.ResponseWriter, r *http.Request) {
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// We're always healthy.
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w.WriteHeader(http.StatusOK)
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io.WriteString(w, http.StatusText(http.StatusOK))
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})
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ctx := context.Background()
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ctx, h.stop = context.WithCancel(ctx)
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go func() { http.Serve(h.ln, h.mux) }()
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go func() { h.overloaded(ctx) }()
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return nil
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}
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func (h *health) OnFinalShutdown() error {
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if !h.nlSetup {
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return nil
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}
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if h.lameduck > 0 {
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log.Infof("Going into lameduck mode for %s", h.lameduck)
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time.Sleep(h.lameduck)
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}
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h.stop()
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h.ln.Close()
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h.nlSetup = false
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return nil
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}
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func (h *health) OnReload() error {
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if !h.nlSetup {
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return nil
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}
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h.stop()
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h.ln.Close()
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h.nlSetup = false
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return nil
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}
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