cron, db, cache and migrations

main.go

@@ -1,5 +1,161 @@
 package main
 
-func main() {
-	println("hello world")
+import (
+	"context"
+	"errors"
+	"github.com/dgraph-io/ristretto"
+	"github.com/docker/docker/api/types"
+	"github.com/docker/docker/client"
+	"github.com/eko/gocache/cache"
+	"github.com/eko/gocache/store"
+	"github.com/gin-gonic/gin"
+	"github.com/go-co-op/gocron"
+	"github.com/jackc/pgx/v4/pgxpool"
+	"go.uber.org/zap"
+	"go.uber.org/zap/zapcore"
+	"io/ioutil"
+	"net/http"
+	"os"
+	"time"
+)
+
+func setupLogger() *zap.Logger {
+	highPriority := zap.LevelEnablerFunc(func(lvl zapcore.Level) bool {
+		return lvl >= zapcore.ErrorLevel
+	})
+	lowPriority := zap.LevelEnablerFunc(func(lvl zapcore.Level) bool {
+		return lvl < zapcore.ErrorLevel
+	})
+	fileDebugging := zapcore.AddSync(ioutil.Discard)
+	fileErrors := zapcore.AddSync(ioutil.Discard)
+
+	consoleDebugging := zapcore.Lock(os.Stdout)
+	consoleErrors := zapcore.Lock(os.Stderr)
+
+	fileEncoder := zapcore.NewJSONEncoder(zap.NewProductionEncoderConfig())
+	consoleEncoder := zapcore.NewConsoleEncoder(zap.NewDevelopmentEncoderConfig())
+
+	core := zapcore.NewTee(
+		zapcore.NewCore(fileEncoder, fileErrors, highPriority),
+		zapcore.NewCore(consoleEncoder, consoleErrors, highPriority),
+		zapcore.NewCore(fileEncoder, fileDebugging, lowPriority),
+		zapcore.NewCore(consoleEncoder, consoleDebugging, lowPriority),
+	)
+
+	logger := zap.New(core)
+	defer logger.Sync()
+	return logger
+}
+func setupApi(l *zap.Logger, cc *cache.Cache) {
+	l.Info("Setting up serverctl setupApi (using gin)")
+
+	r := gin.Default()
+
+	r.GET("/containers", func(c *gin.Context) {
+		type container struct {
+			Name string `json:"name"`
+		}
+		var msg struct {
+			Containers []container `json:"containers"`
+		}
+
+		get, err := cc.Get("docker-containers")
+		if err != nil {
+			c.JSON(http.StatusInternalServerError, gin.H{"message": "could not get containers from container runtime"})
+			return
+		}
+
+		msg.Containers = []container{}
+		for _, cont := range get.([]types.Container) {
+			msg.Containers = append(msg.Containers, container{
+				Name: cont.Names[0],
+			})
+		}
+
+		c.JSON(http.StatusOK, msg)
+	})
+
+	r.Run(":8080")
+
+}
+func setupDocker(l *zap.Logger) *client.Client {
+	l.Info("Setting up Docker")
+	cli, err := client.NewClientWithOpts(client.FromEnv, client.WithAPIVersionNegotiation())
+	if err != nil {
+		panic(err)
+	}
+
+	return cli
+}
+func setupCache(l *zap.Logger) *cache.Cache {
+	l.Info("Setting up cache")
+	ristrettoCache, err := ristretto.NewCache(&ristretto.Config{
+		NumCounters: 1000,
+		MaxCost:     100,
+		BufferItems: 64,
+	})
+	if err != nil {
+		panic(err)
+	}
+	ristrettoStore := store.NewRistretto(ristrettoCache, nil)
+	cacheManager := cache.New(ristrettoStore)
+
+	return cacheManager
+}
+func setupCron(l *zap.Logger, cm *cache.Cache, cc *client.Client) {
+	l.Info("Setting up job scheduler (cron)")
+
+	s := gocron.NewScheduler(time.UTC)
+
+	s.Every(10).Second().Do(func() {
+		l.Debug("getting container list")
+		list, err := cc.ContainerList(context.Background(), types.ContainerListOptions{})
+		if err != nil {
+			l.Warn(err.Error())
+			return
+		}
+
+		err = cm.Set("docker-containers", list, &store.Options{
+			Cost: 2,
+		})
+		if err != nil {
+			l.Warn(err.Error())
+			return
+		}
+	})
+
+	s.StartAsync()
+}
+func setupDatabase(l *zap.Logger) *pgxpool.Pool {
+	l.Info("Setting up database connection")
+	dbUrl := os.Getenv("DATABASE_URL")
+	if dbUrl == "" {
+		panic(errors.New("DATABASE_URL is not set"))
+	}
+	dbpool, err := pgxpool.Connect(context.Background(), dbUrl)
+	if err != nil {
+		panic(err)
+	}
+
+	var greeting string
+	err = dbpool.QueryRow(context.Background(), "select 'Hello, world!'").Scan(&greeting)
+	if err != nil {
+		panic(err)
+	}
+
+	l.Info("Database successfully connected")
+
+	return dbpool
+}
+
+func main() {
+	logger := setupLogger()
+	logger.Info("Starting serverctl")
+
+	cacheM := setupCache(logger)
+	containerClient := setupDocker(logger)
+	setupCron(logger, cacheM, containerClient)
+	dbpool := setupDatabase(logger)
+
+	setupApi(logger, cacheM)
 }