chore: move the go code into a subfolder

apps/api/internal/database/dialect/connections.go

@@ -0,0 +1,87 @@
+package dialect
+
+import (
+	"context"
+	"errors"
+	"reflect"
+
+	pgxdecimal "github.com/jackc/pgx-shopspring-decimal"
+	"github.com/jackc/pgx/v5"
+	"github.com/jackc/pgx/v5/pgtype"
+)
+
+var (
+	ErrIllegalMaxOpenConns = errors.New("MaxOpenConns of the database must be higher than 3 or 0 for unlimited")
+	ErrIllegalMaxIdleConns = errors.New("MaxIdleConns of the database must be higher than 3 or 0 for unlimited")
+)
+
+// ConnectionConfig defines the Max Open and Idle connections for a DB connection pool.
+type ConnectionConfig struct {
+	MaxOpenConns,
+	MaxIdleConns uint32
+	AfterConnect  []func(ctx context.Context, c *pgx.Conn) error
+	BeforeAcquire []func(ctx context.Context, c *pgx.Conn) error
+	AfterRelease  []func(c *pgx.Conn) error
+}
+
+var afterConnectFuncs = []func(ctx context.Context, c *pgx.Conn) error{
+	func(ctx context.Context, c *pgx.Conn) error {
+		pgxdecimal.Register(c.TypeMap())
+		return nil
+	},
+}
+
+func RegisterAfterConnect(f func(ctx context.Context, c *pgx.Conn) error) {
+	afterConnectFuncs = append(afterConnectFuncs, f)
+}
+
+var beforeAcquireFuncs []func(ctx context.Context, c *pgx.Conn) error
+
+func RegisterBeforeAcquire(f func(ctx context.Context, c *pgx.Conn) error) {
+	beforeAcquireFuncs = append(beforeAcquireFuncs, f)
+}
+
+var afterReleaseFuncs []func(c *pgx.Conn) error
+
+func RegisterAfterRelease(f func(c *pgx.Conn) error) {
+	afterReleaseFuncs = append(afterReleaseFuncs, f)
+}
+
+func RegisterDefaultPgTypeVariants[T any](m *pgtype.Map, name, arrayName string) {
+	// T
+	var value T
+	m.RegisterDefaultPgType(value, name)
+
+	// *T
+	valueType := reflect.TypeOf(value)
+	m.RegisterDefaultPgType(reflect.New(valueType).Interface(), name)
+
+	// []T
+	sliceType := reflect.SliceOf(valueType)
+	m.RegisterDefaultPgType(reflect.MakeSlice(sliceType, 0, 0).Interface(), arrayName)
+
+	// *[]T
+	m.RegisterDefaultPgType(reflect.New(sliceType).Interface(), arrayName)
+
+	// []*T
+	sliceOfPointerType := reflect.SliceOf(reflect.TypeOf(reflect.New(valueType).Interface()))
+	m.RegisterDefaultPgType(reflect.MakeSlice(sliceOfPointerType, 0, 0).Interface(), arrayName)
+
+	// *[]*T
+	m.RegisterDefaultPgType(reflect.New(sliceOfPointerType).Interface(), arrayName)
+}
+
+// NewConnectionConfig calculates [ConnectionConfig] values from the passed ratios
+// and returns the config applicable for the requested purpose.
+//
+// openConns and idleConns must be at least 3 or 0, which means no limit.
+// The pusherRatio and spoolerRatio must be between 0 and 1.
+func NewConnectionConfig(openConns, idleConns uint32) *ConnectionConfig {
+	return &ConnectionConfig{
+		MaxOpenConns:  openConns,
+		MaxIdleConns:  idleConns,
+		AfterConnect:  afterConnectFuncs,
+		BeforeAcquire: beforeAcquireFuncs,
+		AfterRelease:  afterReleaseFuncs,
+	}
+}