initial commit

internal/database/database.go

@@ -0,0 +1,100 @@
+package database
+
+import (
+	"context"
+	"database/sql"
+	"embed"
+	"errors"
+	"fmt"
+	"io/fs"
+	"sort"
+	"strings"
+	"time"
+
+	_ "github.com/jackc/pgx/v5/stdlib"
+)
+
+//go:embed migrations/*.sql
+var migrationFiles embed.FS
+
+func Open(ctx context.Context, databaseURL string) (*sql.DB, error) {
+	db, err := sql.Open("pgx", databaseURL)
+	if err != nil {
+		return nil, fmt.Errorf("open database: %w", err)
+	}
+	db.SetMaxOpenConns(20)
+	db.SetMaxIdleConns(5)
+	db.SetConnMaxLifetime(30 * time.Minute)
+	if err := db.PingContext(ctx); err != nil {
+		db.Close()
+		return nil, fmt.Errorf("ping database: %w", err)
+	}
+	return db, nil
+}
+
+func Migrate(ctx context.Context, db *sql.DB) error {
+	if _, err := db.ExecContext(ctx, `CREATE TABLE IF NOT EXISTS schema_migrations (
+		version text PRIMARY KEY,
+		applied_at timestamptz NOT NULL DEFAULT now()
+	)`); err != nil {
+		return fmt.Errorf("create migration table: %w", err)
+	}
+	entries, err := fs.ReadDir(migrationFiles, "migrations")
+	if err != nil {
+		return fmt.Errorf("read migrations: %w", err)
+	}
+	sort.Slice(entries, func(i, j int) bool { return entries[i].Name() < entries[j].Name() })
+	for _, entry := range entries {
+		if entry.IsDir() || !strings.HasSuffix(entry.Name(), ".sql") {
+			continue
+		}
+		var applied bool
+		err := db.QueryRowContext(ctx, `SELECT EXISTS(SELECT 1 FROM schema_migrations WHERE version = $1)`, entry.Name()).Scan(&applied)
+		if err != nil {
+			return fmt.Errorf("check migration %s: %w", entry.Name(), err)
+		}
+		if applied {
+			continue
+		}
+		content, err := migrationFiles.ReadFile("migrations/" + entry.Name())
+		if err != nil {
+			return fmt.Errorf("read migration %s: %w", entry.Name(), err)
+		}
+		up, err := upSection(string(content))
+		if err != nil {
+			return fmt.Errorf("parse migration %s: %w", entry.Name(), err)
+		}
+		tx, err := db.BeginTx(ctx, nil)
+		if err != nil {
+			return fmt.Errorf("begin migration %s: %w", entry.Name(), err)
+		}
+		if _, err = tx.ExecContext(ctx, up); err == nil {
+			_, err = tx.ExecContext(ctx, `INSERT INTO schema_migrations(version) VALUES ($1)`, entry.Name())
+		}
+		if err != nil {
+			tx.Rollback()
+			return fmt.Errorf("apply migration %s: %w", entry.Name(), err)
+		}
+		if err := tx.Commit(); err != nil {
+			return fmt.Errorf("commit migration %s: %w", entry.Name(), err)
+		}
+	}
+	return nil
+}
+
+func upSection(content string) (string, error) {
+	const upMarker = "-- +goose Up"
+	const downMarker = "-- +goose Down"
+	start := strings.Index(content, upMarker)
+	if start < 0 {
+		return "", errors.New("missing up marker")
+	}
+	content = content[start+len(upMarker):]
+	if end := strings.Index(content, downMarker); end >= 0 {
+		content = content[:end]
+	}
+	if strings.TrimSpace(content) == "" {
+		return "", errors.New("empty up migration")
+	}
+	return content, nil
+}