feat: Add health check service and http handler (#17)

Makefile

@@ -3,7 +3,7 @@ PLATFORM := $(shell uname | tr A-Z a-z)
 lint:
 	if [ ! -f ./bin/golangci-lint ] ; \
 	then \
-		curl -sfL https://raw.githubusercontent.com/golangci/golangci-lint/master/install.sh | sh -s v1.37.1; \
+		curl -sfL https://raw.githubusercontent.com/golangci/golangci-lint/master/install.sh | sh -s v1.38.0; \
 	fi;
 	./bin/golangci-lint run
 
@@ -26,4 +26,4 @@ db-migrate: download-golang-migrate-binary
 db-test-migrate: download-golang-migrate-binary
 	./migrate.$(PLATFORM)-amd64 -source file://db/migrations -database ${POSTMAND_TEST_DATABASE_URL} up
 
-.PHONY: lint test download-golang-migrate-binary db-migrate db-test-migrate
+.PHONY: lint test mock download-golang-migrate-binary db-migrate db-test-migrate

cmd/postmand/main.go

@@ -17,6 +17,16 @@ import (
 	"go.uber.org/zap"
 )
 
+func healthcheckServer(db *sqlx.DB, logger *zap.Logger) {
+	pingRepository := repository.NewPing(db)
+	pingService := service.NewPing(pingRepository)
+	pingHandler := handler.NewPing(pingService, logger)
+	mux := http.NewRouter(logger)
+	mux.Get("/healthz", pingHandler.Healthz)
+	server := http.NewServer(mux, env.GetInt("POSTMAND_HEALTH_CHECK_HTTP_PORT", 8000), logger)
+	server.Run()
+}
+
 func main() {
 	// Setup logger
 	logger, err := zap.NewProduction()
@@ -65,6 +75,9 @@ func main() {
 			Aliases: []string{"w"},
 			Usage:   "executes worker to dispatch webhooks",
 			Action: func(c *cli.Context) error {
+				// Start health check
+				go healthcheckServer(db, logger)
+
 				deliveryRepository := repository.NewDelivery(db)
 				pollingInterval := time.Duration(env.GetInt("POSTMAND_POLLING_INTERVAL", 1000)) * time.Millisecond
 				workerService := service.NewWorker(deliveryRepository, logger, pollingInterval)
@@ -77,12 +90,20 @@ func main() {
 			Aliases: []string{"s"},
 			Usage:   "executes http server",
 			Action: func(c *cli.Context) error {
+				// Start health check
+				go healthcheckServer(db, logger)
+
+				// Create repositories
 				webhookRepository := repository.NewWebhook(db)
 				deliveryRepository := repository.NewDelivery(db)
 				deliveryAttemptRepository := repository.NewDeliveryAttempt(db)
+
+				// Create services
 				webhookService := service.NewWebhook(webhookRepository)
 				deliveryService := service.NewDelivery(deliveryRepository)
 				deliveryAttemptService := service.NewDeliveryAttempt(deliveryAttemptRepository)
+
+				// Create http handlers
 				webhookHandler := handler.NewWebhook(webhookService, logger)
 				deliveryHandler := handler.NewDelivery(deliveryService, logger)
 				deliveryAttemptHandler := handler.NewDeliveryAttempt(deliveryAttemptService, logger)

go.mod

@@ -13,7 +13,7 @@ require (
 	github.com/jmoiron/sqlx v1.3.1
 	github.com/joho/godotenv v1.3.0
 	github.com/jpillora/backoff v1.0.0
-	github.com/lib/pq v1.9.0
+	github.com/lib/pq v1.10.0
 	github.com/steinfletcher/apitest v1.5.2
 	github.com/stretchr/testify v1.7.0
 	github.com/urfave/cli/v2 v2.3.0

go.sum

@@ -241,8 +241,8 @@ github.com/lib/pq v1.0.0/go.mod h1:5WUZQaWbwv1U+lTReE5YruASi9Al49XbQIvNi/34Woo=
 github.com/lib/pq v1.1.0/go.mod h1:5WUZQaWbwv1U+lTReE5YruASi9Al49XbQIvNi/34Woo=
 github.com/lib/pq v1.2.0/go.mod h1:5WUZQaWbwv1U+lTReE5YruASi9Al49XbQIvNi/34Woo=
 github.com/lib/pq v1.8.0/go.mod h1:AlVN5x4E4T544tWzH6hKfbfQvm3HdbOxrmggDNAPY9o=
-github.com/lib/pq v1.9.0 h1:L8nSXQQzAYByakOFMTwpjRoHsMJklur4Gi59b6VivR8=
-github.com/lib/pq v1.9.0/go.mod h1:AlVN5x4E4T544tWzH6hKfbfQvm3HdbOxrmggDNAPY9o=
+github.com/lib/pq v1.10.0 h1:Zx5DJFEYQXio93kgXnQ09fXNiUKsqv4OUEu2UtGcB1E=
+github.com/lib/pq v1.10.0/go.mod h1:AlVN5x4E4T544tWzH6hKfbfQvm3HdbOxrmggDNAPY9o=
 github.com/markbates/pkger v0.15.1/go.mod h1:0JoVlrol20BSywW79rN3kdFFsE5xYM+rSCQDXbLhiuI=
 github.com/mattn/go-colorable v0.0.9/go.mod h1:9vuHe8Xs5qXnSaW/c/ABM9alt+Vo+STaOChaDxuIBZU=
 github.com/mattn/go-colorable v0.1.1/go.mod h1:FuOcm+DKB9mbwrcAfNl7/TZVBZ6rcnceauSikq3lYCQ=

http/handler/ping.go

@@ -0,0 +1,45 @@
+package handler
+
+import (
+	"net/http"
+
+	"github.com/allisson/postmand"
+	"go.uber.org/zap"
+)
+
+type pingResponse struct {
+	Success bool `json:"success"`
+}
+
+// Ping implements interface for health check.
+type Ping struct {
+	pingService postmand.PingService
+	logger      *zap.Logger
+}
+
+// Healthz returns health check response.
+func (p Ping) Healthz(w http.ResponseWriter, r *http.Request) {
+	pr := pingResponse{}
+
+	if err := p.pingService.Run(r.Context()); err != nil {
+		p.logger.Error(
+			"service-error",
+			zap.String("name", "PingService"),
+			zap.String("method", "Run"),
+			zap.Error(err),
+		)
+		makeJSONResponse(w, http.StatusInternalServerError, &pr, p.logger)
+		return
+	}
+
+	pr.Success = true
+	makeJSONResponse(w, http.StatusOK, &pr, p.logger)
+}
+
+// NewPing creates a new Ping.
+func NewPing(pingService postmand.PingService, logger *zap.Logger) *Ping {
+	return &Ping{
+		pingService: pingService,
+		logger:      logger,
+	}
+}

http/handler/ping_test.go

@@ -0,0 +1,53 @@
+package handler
+
+import (
+	"errors"
+	nethttp "net/http"
+	"testing"
+
+	"github.com/allisson/postmand/http"
+	"github.com/allisson/postmand/mocks"
+	"github.com/steinfletcher/apitest"
+	"github.com/stretchr/testify/mock"
+	"go.uber.org/zap"
+)
+
+func TestPing(t *testing.T) {
+	logger, _ := zap.NewDevelopment()
+
+	t.Run("With success", func(t *testing.T) {
+		pingService := &mocks.PingService{}
+		pingHandler := NewPing(pingService, logger)
+		router := http.NewRouter(logger)
+		router.Get("/healthz", pingHandler.Healthz)
+
+		pingService.On("Run", mock.Anything).Return(nil)
+		apitest.New().
+			Handler(router).
+			Get("/healthz").
+			Expect(t).
+			Body(`{"success":true}`).
+			Status(nethttp.StatusOK).
+			End()
+
+		pingService.AssertExpectations(t)
+	})
+
+	t.Run("With error", func(t *testing.T) {
+		pingService := &mocks.PingService{}
+		pingHandler := NewPing(pingService, logger)
+		router := http.NewRouter(logger)
+		router.Get("/healthz", pingHandler.Healthz)
+
+		pingService.On("Run", mock.Anything).Return(errors.New("BOOM"))
+		apitest.New().
+			Handler(router).
+			Get("/healthz").
+			Expect(t).
+			Body(`{"success":false}`).
+			Status(nethttp.StatusInternalServerError).
+			End()
+
+		pingService.AssertExpectations(t)
+	})
+}

local.env

@@ -4,3 +4,4 @@ POSTMAND_DATABASE_MIGRATION_DIR='file://db/migrations'
 POSTMAND_DATABASE_MAX_OPEN_CONNS='2'
 POSTMAND_POLLING_INTERVAL='1000'
 POSTMAND_HTTP_PORT='8000'
+POSTMAND_HEALTH_CHECK_HTTP_PORT='8001'

repository.go

@@ -46,3 +46,8 @@ type DeliveryAttemptRepository interface {
 type MigrationRepository interface {
 	Run(ctx context.Context) error
 }
+
+// PingRepository is the interface that will be used to run ping against database.
+type PingRepository interface {
+	Run(ctx context.Context) error
+}

repository/ping.go

@@ -0,0 +1,22 @@
+package repository
+
+import (
+	"context"
+
+	"github.com/jmoiron/sqlx"
+)
+
+// Ping implements postmand.PingRepository interface.
+type Ping struct {
+	db *sqlx.DB
+}
+
+// Run ping operation against the database.
+func (p Ping) Run(ctx context.Context) error {
+	return p.db.PingContext(ctx)
+}
+
+// NewPing will create an implementation of postmand.PingRepository.
+func NewPing(db *sqlx.DB) *Ping {
+	return &Ping{db: db}
+}

repository/ping_test.go

@@ -0,0 +1,17 @@
+package repository
+
+import (
+	"context"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestPing(t *testing.T) {
+	ctx := context.Background()
+	th := newTestHelper()
+	defer th.db.Close()
+
+	err := th.pingRepository.Run(ctx)
+	assert.Nil(t, err)
+}

repository/util_test.go

@@ -21,6 +21,7 @@ type testHelper struct {
 	webhookRepository         *Webhook
 	deliveryRepository        *Delivery
 	deliveryAttemptRepository *DeliveryAttempt
+	pingRepository            *Ping
 }
 
 func newTestHelper() testHelper {
@@ -31,5 +32,6 @@ func newTestHelper() testHelper {
 		webhookRepository:         NewWebhook(db),
 		deliveryRepository:        NewDelivery(db),
 		deliveryAttemptRepository: NewDeliveryAttempt(db),
+		pingRepository:            NewPing(db),
 	}
 }

service.go

@@ -36,3 +36,8 @@ type DeliveryAttemptService interface {
 	Get(ctx context.Context, getOptions RepositoryGetOptions) (*DeliveryAttempt, error)
 	List(ctx context.Context, listOptions RepositoryListOptions) ([]*DeliveryAttempt, error)
 }
+
+// PingService is the interface that will be used to perform ping operation against database.
+type PingService interface {
+	Run(ctx context.Context) error
+}

service/ping.go

@@ -0,0 +1,22 @@
+package service
+
+import (
+	"context"
+
+	"github.com/allisson/postmand"
+)
+
+// Ping implements postmand.PingService interface.
+type Ping struct {
+	pingRepository postmand.PingRepository
+}
+
+// Run ping operation against the database.
+func (p Ping) Run(ctx context.Context) error {
+	return p.pingRepository.Run(ctx)
+}
+
+// NewPing will create an implementation of postmand.PingService.
+func NewPing(pingRepository postmand.PingRepository) *Ping {
+	return &Ping{pingRepository: pingRepository}
+}

service/ping_test.go

@@ -0,0 +1,20 @@
+package service
+
+import (
+	"context"
+	"testing"
+
+	"github.com/allisson/postmand/mocks"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/mock"
+)
+
+func TestPing(t *testing.T) {
+	pingRepository := &mocks.PingRepository{}
+	pingService := NewPing(pingRepository)
+	pingRepository.On("Run", mock.Anything).Return(nil)
+	ctx := context.Background()
+	err := pingService.Run(ctx)
+	assert.Nil(t, err)
+	pingRepository.AssertExpectations(t)
+}