diff options
Diffstat (limited to 'src/kube2msb/vendor/github.com/coreos/pkg/health/health.go')
-rw-r--r-- | src/kube2msb/vendor/github.com/coreos/pkg/health/health.go | 127 |
1 files changed, 127 insertions, 0 deletions
diff --git a/src/kube2msb/vendor/github.com/coreos/pkg/health/health.go b/src/kube2msb/vendor/github.com/coreos/pkg/health/health.go new file mode 100644 index 0000000..a1c3610 --- /dev/null +++ b/src/kube2msb/vendor/github.com/coreos/pkg/health/health.go @@ -0,0 +1,127 @@ +package health + +import ( + "expvar" + "fmt" + "log" + "net/http" + + "github.com/coreos/pkg/httputil" +) + +// Checkables should return nil when the thing they are checking is healthy, and an error otherwise. +type Checkable interface { + Healthy() error +} + +// Checker provides a way to make an endpoint which can be probed for system health. +type Checker struct { + // Checks are the Checkables to be checked when probing. + Checks []Checkable + + // Unhealthyhandler is called when one or more of the checks are unhealthy. + // If not provided DefaultUnhealthyHandler is called. + UnhealthyHandler UnhealthyHandler + + // HealthyHandler is called when all checks are healthy. + // If not provided, DefaultHealthyHandler is called. + HealthyHandler http.HandlerFunc +} + +func (c Checker) ServeHTTP(w http.ResponseWriter, r *http.Request) { + unhealthyHandler := c.UnhealthyHandler + if unhealthyHandler == nil { + unhealthyHandler = DefaultUnhealthyHandler + } + + successHandler := c.HealthyHandler + if successHandler == nil { + successHandler = DefaultHealthyHandler + } + + if r.Method != "GET" { + w.Header().Set("Allow", "GET") + w.WriteHeader(http.StatusMethodNotAllowed) + return + } + + if err := Check(c.Checks); err != nil { + unhealthyHandler(w, r, err) + return + } + + successHandler(w, r) +} + +type UnhealthyHandler func(w http.ResponseWriter, r *http.Request, err error) + +type StatusResponse struct { + Status string `json:"status"` + Details *StatusResponseDetails `json:"details,omitempty"` +} + +type StatusResponseDetails struct { + Code int `json:"code,omitempty"` + Message string `json:"message,omitempty"` +} + +func Check(checks []Checkable) (err error) { + errs := []error{} + for _, c := range checks { + if e := c.Healthy(); e != nil { + errs = append(errs, e) + } + } + + switch len(errs) { + case 0: + err = nil + case 1: + err = errs[0] + default: + err = fmt.Errorf("multiple health check failure: %v", errs) + } + + return +} + +func DefaultHealthyHandler(w http.ResponseWriter, r *http.Request) { + err := httputil.WriteJSONResponse(w, http.StatusOK, StatusResponse{ + Status: "ok", + }) + if err != nil { + // TODO(bobbyrullo): replace with logging from new logging pkg, + // once it lands. + log.Printf("Failed to write JSON response: %v", err) + } +} + +func DefaultUnhealthyHandler(w http.ResponseWriter, r *http.Request, err error) { + writeErr := httputil.WriteJSONResponse(w, http.StatusInternalServerError, StatusResponse{ + Status: "error", + Details: &StatusResponseDetails{ + Code: http.StatusInternalServerError, + Message: err.Error(), + }, + }) + if writeErr != nil { + // TODO(bobbyrullo): replace with logging from new logging pkg, + // once it lands. + log.Printf("Failed to write JSON response: %v", err) + } +} + +// ExpvarHandler is copied from https://golang.org/src/expvar/expvar.go, where it's sadly unexported. +func ExpvarHandler(w http.ResponseWriter, r *http.Request) { + w.Header().Set("Content-Type", "application/json; charset=utf-8") + fmt.Fprintf(w, "{\n") + first := true + expvar.Do(func(kv expvar.KeyValue) { + if !first { + fmt.Fprintf(w, ",\n") + } + first = false + fmt.Fprintf(w, "%q: %s", kv.Key, kv.Value) + }) + fmt.Fprintf(w, "\n}\n") +} |