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9e9d72655d
Make middleware that sets up a (http) handler survive a graceful restart. We calls the middleware's Shutdown function(s). If restart fails the Start function is called again. * middleware/health: OK * middleware/pprof: OK * middleware/metrics: OK All restart OK.
57 lines
786 B
Go
57 lines
786 B
Go
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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)
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var once sync.Once
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type Health struct {
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Addr string
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ln net.Listener
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mux *http.ServeMux
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}
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func health(w http.ResponseWriter, r *http.Request) {
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io.WriteString(w, ok)
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}
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func (h *Health) Start() error {
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if h.Addr == "" {
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h.Addr = defAddr
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}
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once.Do(func() {
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if ln, err := net.Listen("tcp", h.Addr); err != nil {
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log.Printf("[ERROR] Failed to start health handler: %s", err)
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return
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} else {
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h.ln = ln
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}
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h.mux = http.NewServeMux()
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h.mux.HandleFunc(path, health)
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go func() {
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http.Serve(h.ln, h.mux)
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}()
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})
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return nil
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}
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func (h *Health) Shutdown() error {
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if h.ln != nil {
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return h.ln.Close()
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}
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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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