Use TwinProduction/health for health endpoint

vendor/github.com/TwinProduction/health/.gitattributes

@@ -0,0 +1 @@
+* text=lf

vendor/github.com/TwinProduction/health/.gitignore

@@ -0,0 +1,2 @@
+.idea
+*.iml

vendor/github.com/TwinProduction/health/README.md

@@ -0,0 +1,72 @@
+# health
+
+![build](https://github.com/TwinProduction/health/workflows/build/badge.svg?branch=master) 
+[![Go Report Card](https://goreportcard.com/badge/github.com/TwinProduction/health)](https://goreportcard.com/report/github.com/TwinProduction/health)
+[![codecov](https://codecov.io/gh/TwinProduction/health/branch/master/graph/badge.svg)](https://codecov.io/gh/TwinProduction/health)
+[![Go version](https://img.shields.io/github/go-mod/go-version/TwinProduction/health.svg)](https://github.com/TwinProduction/health)
+[![Go Reference](https://pkg.go.dev/badge/github.com/TwinProduction/health.svg)](https://pkg.go.dev/github.com/TwinProduction/health)
+
+Health is a library used for creating a very simple health endpoint.
+
+While implementing a health endpoint is very simple, I've grown tired of implementing 
+it over and over again.
+
+## Installation
+
+```
+go get -u github.com/TwinProduction/health
+```
+
+
+## Usage
+
+To retrieve the handler, you must use `health.Handler()` and are expected to pass it to the router like so:
+```go
+router := http.NewServeMux()
+router.Handle("/health", health.Handler())
+server := &http.Server{
+	Addr:    ":8080",
+	Handler: router,
+}
+```
+
+By default, the handler will return `UP` when the status is down, and `DOWN` when the status is down.
+If you prefer using JSON, however, you may initialize the health handler like so:
+```go
+router.Handle("/health", health.Handler().WithJSON(true))
+```
+The above will cause the response body to become `{"status":"UP"}` and `{"status":"DOWN"}` for both status respectively.
+
+To change the health of the application, you can use `health.SetStatus(<status>)` where `<status>` is one `health.Up`
+or `health.Down`:
+
+```go
+health.SetStatus(health.Up)
+health.SetStatus(health.Down)
+```
+
+### Complete example
+
+```go
+package main
+
+import (
+	"net/http"
+	"time"
+
+	"github.com/TwinProduction/health"
+)
+
+func main() {
+	router := http.NewServeMux()
+	router.Handle("/health", health.Handler())
+	server := &http.Server{
+		Addr:         "0.0.0.0:8080",
+		Handler:      router,
+		ReadTimeout:  15 * time.Second,
+		WriteTimeout: 15 * time.Second,
+		IdleTimeout:  15 * time.Second,
+	}
+	server.ListenAndServe()
+}
+```

vendor/github.com/TwinProduction/health/go.mod

@@ -0,0 +1,3 @@
+module github.com/TwinProduction/health
+
+go 1.15

vendor/github.com/TwinProduction/health/health.go

@@ -0,0 +1,51 @@
+package health
+
+import "net/http"
+
+var (
+	handler = &healthHandler{
+		useJSON: false,
+		status:  Up,
+	}
+)
+
+type healthHandler struct {
+	useJSON bool
+	status  Status
+}
+
+// WithJSON configures whether the handler should output a response in JSON or in raw text
+//
+// Defaults to false
+func (h *healthHandler) WithJSON(v bool) *healthHandler {
+	h.useJSON = v
+	return h
+}
+
+func (h healthHandler) ServeHTTP(writer http.ResponseWriter, request *http.Request) {
+	var status int
+	var body []byte
+	if h.status == Up {
+		status = http.StatusOK
+	} else {
+		status = http.StatusInternalServerError
+	}
+	if h.useJSON {
+		writer.Header().Set("Content-Type", "application/json")
+		body = []byte(`{"status":"` + h.status + `"}`)
+	} else {
+		body = []byte(h.status)
+	}
+	writer.WriteHeader(status)
+	_, _ = writer.Write(body)
+}
+
+// Handler retrieves the health handler
+func Handler() *healthHandler {
+	return handler
+}
+
+// SetStatus sets the status to be reflected by the health handler
+func SetStatus(status Status) {
+	handler.status = status
+}

vendor/github.com/TwinProduction/health/status.go

@@ -0,0 +1,8 @@
+package health
+
+type Status string
+
+var (
+	Down Status = "DOWN"
+	Up   Status = "UP"
+)