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804f745951
* plugin/health: make reload work Remove the once.Do from the startup, so we can re-bind the HTTP listener. Also clarify the usage of health in multiple server blocks (this is not the best approach - but there isn't a generic solution at this point). Manual tested as we lack testing infra, i.e kill -SIGUSR1 and some CURLing of the health endpoint. * Readme test fix * update * dont need this
87 lines
1.5 KiB
Go
87 lines
1.5 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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"io"
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"log"
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"net"
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"net/http"
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"sync"
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"time"
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)
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// Health implements healthchecks by polling plugins.
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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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mux *http.ServeMux
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// A slice of Healthers that the health plugin will poll every second for their health status.
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h []Healther
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sync.RWMutex
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ok bool // ok is the global boolean indicating an all healthy plugin stack
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stop chan bool
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pollstop chan bool
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}
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// newHealth returns a new initialized health.
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func newHealth(addr string) *health {
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return &health{Addr: addr, stop: make(chan bool), pollstop: make(chan bool)}
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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 = defAddr
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}
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ln, err := net.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.mux.HandleFunc(path, func(w http.ResponseWriter, r *http.Request) {
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if h.Ok() {
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w.WriteHeader(http.StatusOK)
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io.WriteString(w, ok)
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return
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}
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w.WriteHeader(http.StatusServiceUnavailable)
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})
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go func() { http.Serve(h.ln, h.mux) }()
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go func() { h.overloaded() }()
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return nil
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}
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func (h *health) OnShutdown() error {
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// Stop polling plugins
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h.pollstop <- true
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// NACK health
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h.SetOk(false)
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if h.lameduck > 0 {
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log.Printf("[INFO] Going into lameduck mode for %s", h.lameduck)
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time.Sleep(h.lameduck)
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}
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if h.ln != nil {
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return h.ln.Close()
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}
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h.stop <- true
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return nil
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}
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const (
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ok = "OK"
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defAddr = ":8080"
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path = "/health"
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)
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