added api structure, container and health endpoint

.air.toml

@@ -0,0 +1,36 @@
+root = "."
+testdata_dir = "testdata"
+tmp_dir = "tmp"
+
+[build]
+  bin = "./tmp/main"
+  cmd = "go build -o ./tmp/main ./app/cmd"
+  delay = 1000
+  exclude_dir = ["assets", "tmp", "vendor", "testdata"]
+  exclude_file = []
+  exclude_regex = ["_test.go"]
+  exclude_unchanged = false
+  follow_symlink = false
+  full_bin = ""
+  include_dir = []
+  include_ext = ["go", "tpl", "tmpl", "html"]
+  kill_delay = "0s"
+  log = "build-errors.log"
+  send_interrupt = false
+  stop_on_error = true
+
+[color]
+  app = ""
+  build = "yellow"
+  main = "magenta"
+  runner = "green"
+  watcher = "cyan"
+
+[log]
+  time = false
+
+[misc]
+  clean_on_exit = false
+
+[screen]
+  clear_on_rebuild = false

Makefile

@@ -4,3 +4,4 @@ create-migration:
 
 init-db:
 	docker-compose run migration
+	docker-compose up api

app/cmd/main.go

@@ -0,0 +1,117 @@
+package main
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"net/http"
+	"os"
+	"os/signal"
+	"syscall"
+	"time"
+
+	api "github.com/aorticweb/msg-app/app/handlers"
+	"github.com/sirupsen/logrus"
+	"gorm.io/driver/postgres"
+	"gorm.io/gorm"
+)
+
+var dbConnectionWaitTime time.Duration = 5 * time.Minute
+var shutdownTimeout time.Duration = 3 * time.Second
+var serverListenAddr string = ":8080"
+
+func dbConnection(url string) (*gorm.DB, error) {
+	return gorm.Open(postgres.Open(url), &gorm.Config{})
+}
+
+func dbUrl() (string, error) {
+	url, exist := os.LookupEnv("POSTGRES_URL")
+	if !exist {
+		return "", errors.New("Env varialbe POSTGRES_URL is not set")
+	}
+	return url, nil
+}
+
+// waitForDB ... wait up to timeout for database to be up then return connection
+func waitForDB(timeout time.Duration) (*gorm.DB, error) {
+	url, err := dbUrl()
+	if err != nil {
+		return nil, err
+	}
+	db, err := dbConnection(url)
+	for start := time.Now(); time.Since(start) < timeout; {
+		if err == nil {
+			break
+		}
+		db, err = dbConnection(url)
+		time.Sleep(1 * time.Second)
+	}
+	return db, err
+}
+
+func registerKillSwitch() chan os.Signal {
+	shutdown := make(chan os.Signal, 1)
+	signal.Notify(shutdown, os.Interrupt, syscall.SIGTERM, syscall.SIGINT)
+	return shutdown
+}
+
+func gracefullyShutdown(server *http.Server) error {
+	ctx, cancel := context.WithTimeout(context.Background(), shutdownTimeout)
+	defer cancel()
+
+	err := server.Shutdown(ctx)
+	if err == nil {
+		return nil
+	}
+	logrus.Error("Server shutdown did not succeed in %v: %v", shutdownTimeout, err)
+	err = server.Close()
+
+	if err != nil {
+		return fmt.Errorf("Server close failed: %v", err)
+	}
+	logrus.Info("Bye Bye")
+	return nil
+}
+
+func waitForKillSwitch(kill chan os.Signal, server *http.Server) {
+	<-kill
+	gracefullyShutdown(server)
+}
+
+func setupServer(logger *logrus.Logger) (*http.Server, error) {
+	db, err := waitForDB(dbConnectionWaitTime)
+	if err != nil {
+		logger.Error("Failed to fetch database connection")
+		return nil, err
+	}
+	killSwitch := registerKillSwitch()
+	API := api.NewAPI(db, logger)
+	server := http.Server{
+		Addr:         serverListenAddr,
+		Handler:      API,
+		ReadTimeout:  10 * time.Second,
+		WriteTimeout: 10 * time.Second,
+	}
+	go waitForKillSwitch(killSwitch, &server)
+	return &server, nil
+}
+
+func must(err error, logger *logrus.Logger) {
+	if err != nil {
+		logger.Fatal(err)
+		os.Exit(1)
+	}
+}
+
+func main() {
+	logger := logrus.New()
+	server, err := setupServer(logger)
+	must(err, logger)
+	logger.Info("API says Hello\n")
+	err = server.ListenAndServe()
+	if err == http.ErrServerClosed {
+		logger.Info("API says Goodbye\n")
+		os.Exit(0)
+	}
+	must(err, logger)
+}

app/handlers/health.go

@@ -0,0 +1,19 @@
+package api
+
+import (
+	"net/http"
+)
+
+func (a *API) handleHealth() http.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) {
+		var c int
+		a.db.Raw("SELECT COUNT(table_name) FROM information_schema.tables WHERE table_schema = 'public' AND table_name = 'user';").Scan(&c)
+		if c != 1 {
+			a.logger.Error("Health check failed, could not reach database")
+			w.WriteHeader(http.StatusExpectationFailed)
+			return
+		}
+		w.WriteHeader(http.StatusOK)
+		return
+	}
+}

app/handlers/routes.go

@@ -0,0 +1,29 @@
+package api
+
+import (
+	"net/http"
+
+	"github.com/gorilla/mux"
+	"github.com/sirupsen/logrus"
+	"gorm.io/gorm"
+)
+
+type API struct {
+	db     *gorm.DB
+	router *mux.Router
+	logger *logrus.Logger
+}
+
+func (a *API) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	a.router.ServeHTTP(w, r)
+}
+
+func NewAPI(db *gorm.DB, logger *logrus.Logger) *API {
+	a := &API{db, mux.NewRouter(), logger}
+	a.routes()
+	return a
+}
+
+func (a *API) routes() {
+	a.router.HandleFunc("/health", a.handleHealth()).Methods("GET")
+}

containers/api/Dockerfile

@@ -0,0 +1,21 @@
+FROM golang:latest as dev
+
+EXPOSE 8080
+
+COPY . /msg-app
+WORKDIR /msg-app
+
+RUN curl -sSfL https://raw.githubusercontent.com/cosmtrek/air/master/install.sh | sh -s -- -b $(go env GOPATH)/bin
+RUN cd app/cmd/ && CGO_ENABLED=0 GOOS=linux go build -v -o api
+
+CMD ["air"]
+
+FROM scratch as prod
+
+# FROM ubuntu:bionic as prod
+
+EXPOSE 8080
+
+COPY --from=dev /msg-app/app/cmd/api /bin/api
+
+CMD ["/bin/api"]

docker-compose.yml

@@ -2,6 +2,21 @@
 version: "3.9"
 services:
 
+  api:
+    image: aorticweb/msg-app-api
+    build:
+      context: .
+      dockerfile: containers/api/Dockerfile
+      target: dev
+    environment:
+      POSTGRES_URL: "postgres://${POSTGRES_USER}:${POSTGRES_PASSWORD}@postgres:5432/${POSTGRES_DB}?sslmode=disable"
+    volumes:
+    - ./:/msg-app:rw
+    depends_on:
+      - migration
+    ports:
+      - 8080:8080
+
   migration:
     image: aorticweb/msg-app-migration
     build:

go.mod

@@ -1,5 +1,23 @@
-module github.com/aorticweb/msg-app.git
+module github.com/aorticweb/msg-app
 
 go 1.17
 
-require github.com/gorilla/mux v1.8.0 // indirect
+require (
+	github.com/gorilla/mux v1.8.0 // indirect
+	github.com/jackc/chunkreader/v2 v2.0.1 // indirect
+	github.com/jackc/pgconn v1.10.1 // indirect
+	github.com/jackc/pgio v1.0.0 // indirect
+	github.com/jackc/pgpassfile v1.0.0 // indirect
+	github.com/jackc/pgproto3/v2 v2.2.0 // indirect
+	github.com/jackc/pgservicefile v0.0.0-20200714003250-2b9c44734f2b // indirect
+	github.com/jackc/pgtype v1.9.0 // indirect
+	github.com/jackc/pgx/v4 v4.14.0 // indirect
+	github.com/jinzhu/inflection v1.0.0 // indirect
+	github.com/jinzhu/now v1.1.4 // indirect
+	github.com/sirupsen/logrus v1.8.1 // indirect
+	golang.org/x/crypto v0.0.0-20210921155107-089bfa567519 // indirect
+	golang.org/x/sys v0.0.0-20210615035016-665e8c7367d1 // indirect
+	golang.org/x/text v0.3.7 // indirect
+	gorm.io/driver/postgres v1.2.3 // indirect
+	gorm.io/gorm v1.22.5 // indirect
+)