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67 lines
1.7 KiB
67 lines
1.7 KiB
4 years ago
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package health
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import (
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"context"
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"encoding/json"
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"net/http"
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)
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// CheckerFunc wraps the CheckHealth method.
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//
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// CheckHealth returns nil if the resource is healthy, or a non-nil
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// error if the resource is not healthy. CheckHealth must be safe to
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// call from multiple goroutines.
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type CheckerFunc func(ctx context.Context) error
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// Handler is an HTTP handler that reports on the success of an
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// aggregate of Checkers. The zero value is always healthy.
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type Handler struct {
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checkers map[string]CheckerFunc
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observers map[string]CheckerFunc
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}
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// NewHandler new a health handler.
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func NewHandler() *Handler {
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return &Handler{
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checkers: make(map[string]CheckerFunc),
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observers: make(map[string]CheckerFunc),
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}
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}
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// AddChecker adds a new check to the handler.
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func (h *Handler) AddChecker(name string, c CheckerFunc) {
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h.checkers[name] = c
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}
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// AddObserver adds a new check to the handler but it does not fail the entire status.
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func (h *Handler) AddObserver(name string, c CheckerFunc) {
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h.observers[name] = c
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}
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// ServeHTTP returns 200 if it is healthy, 500 otherwise.
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func (h *Handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
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code := http.StatusOK
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results := make(map[string]string, len(h.checkers))
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for name, checker := range h.checkers {
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if err := checker(r.Context()); err != nil {
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code = http.StatusInternalServerError
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results[name] = err.Error()
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} else {
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results[name] = "OK"
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}
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}
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for name, checker := range h.observers {
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if err := checker(r.Context()); err != nil {
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results[name] = err.Error()
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} else {
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results[name] = "OK"
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}
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}
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w.WriteHeader(code)
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w.Header().Set("Content-Type", "application/json; charset=utf-8")
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json.NewEncoder(w).Encode(results)
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}
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