handler.go

/*
	Copyright NetFoundry Inc.

	Licensed under the Apache License, Version 2.0 (the "License");
	you may not use this file except in compliance with the License.
	You may obtain a copy of the License at

	https://www.apache.org/licenses/LICENSE-2.0

	Unless required by applicable law or agreed to in writing, software
	distributed under the License is distributed on an "AS IS" BASIS,
	WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	See the License for the specific language governing permissions and
	limitations under the License.
*/

package health

import (
	"encoding/json"
	"fmt"
	gosundheit "github.com/AppsFlyer/go-sundheit"
	"github.com/openziti/xweb/v2"
	"github.com/sirupsen/logrus"
	"net/http"
	"strings"
	"time"
)

const (
	Binding = "health-checks"
)

var _ xweb.ApiHandlerFactory = &HealthCheckApiFactory{}

func NewHealthCheckApiFactory(healthChecker gosundheit.Health) *HealthCheckApiFactory {
	return &HealthCheckApiFactory{
		healthChecker: healthChecker,
	}
}

type HealthCheckApiFactory struct {
	healthChecker gosundheit.Health
}

func (factory HealthCheckApiFactory) Validate(*xweb.InstanceConfig) error {
	return nil
}

func (factory HealthCheckApiFactory) Binding() string {
	return Binding
}

func (factory HealthCheckApiFactory) New(_ *xweb.ServerConfig, options map[interface{}]interface{}) (xweb.ApiHandler, error) {
	return &HealthCheckApiHandler{
		healthChecker: factory.healthChecker,
		options:       options,
	}, nil
}

type HealthCheckApiHandler struct {
	options       map[interface{}]interface{}
	healthChecker gosundheit.Health
}

func (self *HealthCheckApiHandler) Binding() string {
	return Binding
}

func (self *HealthCheckApiHandler) Options() map[interface{}]interface{} {
	return self.options
}

func (self *HealthCheckApiHandler) RootPath() string {
	return "/health-checks"
}

func (self *HealthCheckApiHandler) IsHandler(r *http.Request) bool {
	return strings.HasPrefix(r.URL.Path, self.RootPath())
}

func (self *HealthCheckApiHandler) ServeHTTP(w http.ResponseWriter, request *http.Request) {
	output := map[string]interface{}{}
	output["meta"] = map[string]interface{}{}

	data := map[string]interface{}{}
	output["data"] = data

	w.Header().Set("Content-Type", "application/json")
	encoder := json.NewEncoder(w)
	encoder.SetIndent("", "    ")

	results, healthy := self.healthChecker.Results()
	data["healthy"] = healthy
	var checks []map[string]interface{}

	shortFormat := request.URL.Query().Get("type") == "short"

	for id, result := range results {
		check := map[string]interface{}{}
		checks = append(checks, check)
		check["id"] = id
		check["healthy"] = result.IsHealthy()
		if !shortFormat {
			check["lastCheckDuration"] = fmt.Sprintf("%v", result.Duration)
			check["lastCheckTime"] = result.Timestamp.UTC().Format(time.RFC3339)

			if result.Error != nil {
				check["err"] = result.Error
				check["consecutiveFailures"] = result.ContiguousFailures
			}

			if result.TimeOfFirstFailure != nil {
				check["failingSince"] = result.TimeOfFirstFailure.UTC().Format(time.RFC3339)
			}
			if result.Details != "didn't run yet" {
				check["details"] = result.Details
			}
		}
	}

	data["checks"] = checks
	if err := encoder.Encode(output); err != nil {
		logrus.WithError(err).Error("failure encoding health check results")
	}
}