32 lines
1 KiB
Go
32 lines
1 KiB
Go
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package middlewares
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import (
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"net/http"
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"github.com/containous/traefik/healthcheck"
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)
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// EmptyBackendHandler is a middlware that checks whether the current Backend
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// has at least one active Server in respect to the healthchecks and if this
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// is not the case, it will stop the middleware chain and respond with 503.
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type EmptyBackendHandler struct {
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lb healthcheck.LoadBalancer
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next http.Handler
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}
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// NewEmptyBackendHandler creates a new EmptyBackendHandler instance.
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func NewEmptyBackendHandler(lb healthcheck.LoadBalancer, next http.Handler) *EmptyBackendHandler {
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return &EmptyBackendHandler{lb: lb, next: next}
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}
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// ServeHTTP responds with 503 when there is no active Server and otherwise
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// invokes the next handler in the middleware chain.
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func (h *EmptyBackendHandler) ServeHTTP(rw http.ResponseWriter, r *http.Request) {
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if len(h.lb.Servers()) == 0 {
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rw.WriteHeader(http.StatusServiceUnavailable)
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rw.Write([]byte(http.StatusText(http.StatusServiceUnavailable)))
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} else {
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h.next.ServeHTTP(rw, r)
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}
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}
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