Put project modules under pkg directory

pkg/cgnolink/database/database.go

@@ -0,0 +1,65 @@
+package database
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"github.com/jackc/pgx/v4/pgxpool"
+	"github.com/knadh/koanf"
+	"github.com/rs/zerolog/log"
+	"time"
+)
+
+func InitPool(config *koanf.Koanf) *pgxpool.Pool {
+	pool := NewPool(config)
+
+	if err := runMigrations(pool); err != nil {
+		log.Fatal().Err(err).Msg("Couldn't apply migrations")
+		panic(err)
+	}
+
+	return pool
+}
+
+func NewPool(config *koanf.Koanf) *pgxpool.Pool {
+	connStr, err := getConnectionString(config)
+	if err != nil {
+		log.Fatal().Err(err).Msg("Couldn't construct DB connection string")
+		panic(err)
+	}
+
+	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
+	defer cancel()
+
+	pool, err := pgxpool.Connect(ctx, connStr)
+	if err != nil {
+		log.Fatal().Err(err).Msg("Couldn't connect to DB")
+		panic(err)
+	}
+
+	return pool
+}
+
+func getConnectionString(config *koanf.Koanf) (string, error) {
+	username := config.String("db.username")
+	if username == "" {
+		return "", errors.New("database username is missing")
+	}
+
+	password := config.String("db.password")
+	if password == "" {
+		return "", errors.New("database password is missing")
+	}
+
+	name := config.String("db.name")
+	if name == "" {
+		return "", errors.New("database name is missing")
+	}
+
+	host := config.String("db.host")
+	if name == "" {
+		return "", errors.New("database host is missing")
+	}
+
+	return fmt.Sprintf("postgresql://%s:%s@%s/%s", username, password, host, name), nil
+}

pkg/cgnolink/database/migrate.go

@@ -0,0 +1,33 @@
+package database
+
+import (
+	"context"
+	"github.com/jackc/pgx/v4/pgxpool"
+	"github.com/jackc/tern/migrate"
+	"time"
+)
+
+func runMigrations(pool *pgxpool.Pool) (err error) {
+	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
+	defer cancel()
+
+	conn, err := pool.Acquire(ctx)
+	if err != nil {
+		return
+	}
+
+	migrator, err := migrate.NewMigrator(ctx, conn.Conn(), "schema_version")
+	if err != nil {
+		return
+	}
+
+	if err = migrator.LoadMigrations("./migrations"); err != nil {
+		return
+	}
+
+	if err = migrator.Migrate(ctx); err != nil {
+		return
+	}
+
+	return
+}

pkg/cgnolink/database/util.go

@@ -0,0 +1,15 @@
+package database
+
+import (
+	"github.com/jackc/pgx/v4/pgxpool"
+	"github.com/rs/zerolog/log"
+)
+
+func LogPoolState(pool *pgxpool.Pool, message string) {
+	stat := pool.Stat()
+	log.Info().
+		Int32("acquired_conns", stat.AcquiredConns()).
+		Int32("idle_conns", stat.IdleConns()).
+		Int32("total_conns", stat.TotalConns()).
+		Msg(message)
+}