build(seeds): add a seeds package with the necessary logic to seed th…

…e database

cmd/seeder/main.go

@@ -0,0 +1,34 @@
+package main
+
+import (
+	"flag"
+	"log"
+	"os"
+
+	"github.com/danvergara/dblab/db/seeds"
+	"github.com/danvergara/dblab/pkg/config"
+	"github.com/jmoiron/sqlx"
+)
+
+func main() {
+	handleArgs()
+}
+
+func handleArgs() {
+	flag.Parse()
+	args := flag.Args()
+	cfg := config.Get()
+
+	if len(args) >= 1 {
+		switch args[0] {
+		case "seed":
+			connString := cfg.GetDBConnStr()
+			db, err := sqlx.Open(cfg.Driver(), connString)
+			if err != nil {
+				log.Fatalf("Error opening DB: %v", err)
+			}
+			seeds.Execute(db, args[1:]...)
+			os.Exit(0)
+		}
+	}
+}

db/seeds/seeder.go

@@ -0,0 +1,53 @@
+package seeds
+
+import (
+	"log"
+	"reflect"
+
+	"github.com/jmoiron/sqlx"
+)
+
+// Seed type.
+type Seed struct {
+	db *sqlx.DB
+}
+
+// Execute will executes the given seeder method.
+func Execute(db *sqlx.DB, seedMethodNames ...string) {
+	s := Seed{
+		db: db,
+	}
+
+	seedType := reflect.TypeOf(s)
+
+	// Executes all seeders if no method is given.
+	if len(seedMethodNames) == 0 {
+		log.Println("running all seeder...")
+		// We are looping over the method on a Seed struct.
+		for i := 0; i < seedType.NumMethod(); i++ {
+			// Get the method in the current iteration.
+			method := seedType.Method(i)
+			// Execute seeder.
+			seed(s, method.Name)
+		}
+	}
+
+	// Execute only the given method names
+	for _, item := range seedMethodNames {
+		seed(s, item)
+	}
+}
+
+func seed(s Seed, seedMethodName string) {
+	// Get the reflect value of the method.
+	m := reflect.ValueOf(s).MethodByName(seedMethodName)
+	// Exit if the method diesn't exist.
+	if !m.IsValid() {
+		log.Fatal("no method called", seedMethodName)
+	}
+
+	// Execute the method.
+	log.Println("seeding", seedMethodName, "...")
+	m.Call(nil)
+	log.Println("seed", seedMethodName, "succeded")
+}