34 lines
1,018 B
Go
34 lines
1,018 B
Go
package emptybackendhandler
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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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// EmptyBackend is a middleware 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 emptyBackend struct {
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next healthcheck.BalancerHandler
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}
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// New creates a new EmptyBackend middleware.
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func New(lb healthcheck.BalancerHandler) http.Handler {
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return &emptyBackend{next: lb}
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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 (e *emptyBackend) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
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if len(e.next.Servers()) == 0 {
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rw.WriteHeader(http.StatusServiceUnavailable)
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_, err := rw.Write([]byte(http.StatusText(http.StatusServiceUnavailable)))
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if err != nil {
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http.Error(rw, err.Error(), http.StatusInternalServerError)
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}
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} else {
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e.next.ServeHTTP(rw, req)
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}
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}
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