From e77d3c4d5e211c1fd6886eb7c9fbb15ff1b8058f Mon Sep 17 00:00:00 2001
From: Deepak <dmallubhotla+github@gmail.com>
Date: Thu, 31 Dec 2020 18:47:27 -0600
Subject: [PATCH] Adds health check and test

---
 routes/health.go           | 58 +++++++++++++++++++++++++
 routes/health_test.go      | 87 ++++++++++++++++++++++++++++++++++++++
 routes/plans_test.go       |  2 +-
 routes/route_model_test.go |  4 +-
 routes/routes.go           |  1 +
 5 files changed, 149 insertions(+), 3 deletions(-)
 create mode 100644 routes/health.go
 create mode 100644 routes/health_test.go

diff --git a/routes/health.go b/routes/health.go
new file mode 100644
index 0000000..b03ddab
--- /dev/null
+++ b/routes/health.go
@@ -0,0 +1,58 @@
+package routes
+
+import (
+	"encoding/json"
+	"gitea.deepak.science/deepak/gogmagog/models"
+	"github.com/go-chi/chi"
+	"net/http"
+)
+
+func newHealthRouter(m *models.Model) http.Handler {
+	router := chi.NewRouter()
+	router.Get("/", getHealthFunc(m))
+	return router
+}
+
+type healthCheck struct {
+	Name    string `json:"name"`
+	Healthy bool   `json:"healthy"`
+	Message string `json:"message"`
+}
+
+func getHealthFunc(m *models.Model) http.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) {
+		var healths []*healthCheck
+
+		healths = append(healths, dbHealth(m))
+
+		code := http.StatusOK
+		for _, h := range healths {
+			if !h.Healthy {
+				code = http.StatusInternalServerError
+				break
+			}
+		}
+
+		w.WriteHeader(code)
+		w.Header().Add("Content-Type", "application/json")
+		if err := json.NewEncoder(w).Encode(healths); err != nil {
+			serverError(w, err)
+		}
+	}
+}
+
+func dbHealth(m *models.Model) *healthCheck {
+	errMessage := ""
+	health := true
+	name := "Store"
+	err := m.Healthy()
+	if err != nil {
+		errMessage = err.Error()
+		health = false
+	}
+	return &healthCheck{
+		Name:    name,
+		Healthy: health,
+		Message: errMessage,
+	}
+}
diff --git a/routes/health_test.go b/routes/health_test.go
new file mode 100644
index 0000000..92902b3
--- /dev/null
+++ b/routes/health_test.go
@@ -0,0 +1,87 @@
+package routes_test
+
+import (
+	"fmt"
+	"gitea.deepak.science/deepak/gogmagog/routes"
+	"github.com/stretchr/testify/assert"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+)
+
+func TestEmptyHeatlhErrorWriter(t *testing.T) {
+	// set up
+	assert := assert.New(t)
+
+	m := getEmptyModel()
+
+	router := routes.NewRouter(m)
+	req, _ := http.NewRequest("GET", "/health", nil)
+
+	rr := NewBadWriter()
+
+	// function under test
+	router.ServeHTTP(rr, req)
+
+	// check results
+	status := rr.Code
+	assert.Equal(http.StatusInternalServerError, status)
+
+}
+
+func TestEmptyHealth(t *testing.T) {
+	// set up
+	assert := assert.New(t)
+	m := getEmptyModel()
+	router := routes.NewRouter(m)
+	req, _ := http.NewRequest("GET", "/health", nil)
+
+	rr := httptest.NewRecorder()
+
+	// function under test
+	router.ServeHTTP(rr, req)
+
+	// check results
+	status := rr.Code
+	assert.Equal(http.StatusOK, status)
+	expected := `[
+		{
+			"name": "Store",
+			"healthy": true,
+			"message": ""
+		}
+	]`
+
+	assert.JSONEq(expected, rr.Body.String())
+	contentType := rr.Header().Get("Content-Type")
+	assert.Equal("application/json", contentType)
+}
+
+func TestUnhealthyDB(t *testing.T) {
+	// set up
+	assert := assert.New(t)
+	errorMsg := "error"
+	m := getErrorModel(errorMsg)
+	router := routes.NewRouter(m)
+	req, _ := http.NewRequest("GET", "/health", nil)
+
+	rr := httptest.NewRecorder()
+
+	// function under test
+	router.ServeHTTP(rr, req)
+
+	// check results
+	status := rr.Code
+	assert.Equal(http.StatusInternalServerError, status)
+	expected := fmt.Sprintf(`[
+		{
+			"name": "Store",
+			"healthy": false,
+			"message": "%s"
+		}
+	]`, errorMsg)
+
+	assert.JSONEq(expected, rr.Body.String())
+	contentType := rr.Header().Get("Content-Type")
+	assert.Equal("application/json", contentType)
+}
diff --git a/routes/plans_test.go b/routes/plans_test.go
index 62a30f6..5f0cc15 100644
--- a/routes/plans_test.go
+++ b/routes/plans_test.go
@@ -66,7 +66,7 @@ func TestErrorPlan(t *testing.T) {
 	// set up
 	assert := assert.New(t)
 
-	m := getErrorModel()
+	m := getErrorModel("Model always errors")
 
 	router := routes.NewRouter(m)
 	req, _ := http.NewRequest("GET", "/plans", nil)
diff --git a/routes/route_model_test.go b/routes/route_model_test.go
index 3742924..6146e2c 100644
--- a/routes/route_model_test.go
+++ b/routes/route_model_test.go
@@ -87,7 +87,7 @@ type errorStore struct {
 	error error
 }
 
-func getErrorModel() *models.Model {
-	e := &errorStore{error: fmt.Errorf("Model always errors")}
+func getErrorModel(errorMsg string) *models.Model {
+	e := &errorStore{error: fmt.Errorf(errorMsg)}
 	return models.New(e)
 }
diff --git a/routes/routes.go b/routes/routes.go
index e2a9f1e..15ee2d4 100644
--- a/routes/routes.go
+++ b/routes/routes.go
@@ -13,6 +13,7 @@ func NewRouter(m *models.Model) http.Handler {
 	router.MethodNotAllowed(methodNotAllowedHandler)
 	router.NotFound(notFoundHandler)
 	router.Mount("/plans", newPlanRouter(m))
+	router.Mount("/health", newHealthRouter(m))
 	router.Get("/ping", ping)
 	return router
 }