feat(db): migrate from MySQL to PostgreSQL

Replace MySQL driver with pgx/v5 and pgxpool:
- Update sqlc to use postgresql engine
- Convert query.sql to PostgreSQL syntax ($1 params, CASE WHEN,
  ANY() arrays)
- Replace sql.DB with pgxpool.Pool throughout
- Change nullable types from sql.Null* to pgtype.*
- Update ID types from uint32 to int64 for PostgreSQL compatibility
- Delete MySQL-specific dynamic_connect.go
- Add opentelemetry.gowrap template for tracing

ntpdb/tx.go

@@ -2,7 +2,11 @@ package ntpdb
 
 import (
 	"context"
-	"database/sql"
+	"errors"
+
+	"github.com/jackc/pgx/v5"
+	"go.ntppool.org/common/logger"
+	"go.opentelemetry.io/otel/trace"
 )
 
 type QuerierTx interface {
@@ -11,14 +15,17 @@ type QuerierTx interface {
 	Begin(ctx context.Context) (QuerierTx, error)
 	Commit(ctx context.Context) error
 	Rollback(ctx context.Context) error
+
+	// Conn returns the connection used by this transaction
+	Conn() *pgx.Conn
 }
 
 type Beginner interface {
-	Begin(context.Context) (sql.Tx, error)
+	Begin(context.Context) (pgx.Tx, error)
 }
 
 type Tx interface {
-	Begin(context.Context) (sql.Tx, error)
+	Begin(context.Context) (pgx.Tx, error)
 	Commit(ctx context.Context) error
 	Rollback(ctx context.Context) error
 }
@@ -28,21 +35,33 @@ func (q *Queries) Begin(ctx context.Context) (QuerierTx, error) {
 	if err != nil {
 		return nil, err
 	}
-	return &Queries{db: &tx}, nil
+	return &Queries{db: tx}, nil
 }
 
 func (q *Queries) Commit(ctx context.Context) error {
 	tx, ok := q.db.(Tx)
 	if !ok {
-		return sql.ErrTxDone
+		// Commit called on Queries with dbpool, so treat as transaction already committed
+		return pgx.ErrTxClosed
 	}
 	return tx.Commit(ctx)
 }
 
+func (q *Queries) Conn() *pgx.Conn {
+	// pgx.Tx is an interface that has Conn() method
+	tx, ok := q.db.(pgx.Tx)
+	if !ok {
+		logger.Setup().Error("could not get connection from QuerierTx")
+		return nil
+	}
+	return tx.Conn()
+}
+
 func (q *Queries) Rollback(ctx context.Context) error {
 	tx, ok := q.db.(Tx)
 	if !ok {
-		return sql.ErrTxDone
+		// Rollback called on Queries with dbpool, so treat as transaction already committed
+		return pgx.ErrTxClosed
 	}
 	return tx.Rollback(ctx)
 }
@@ -62,3 +81,41 @@ func (wq *WrappedQuerier) Begin(ctx context.Context) (QuerierTx, error) {
 	}
 	return NewWrappedQuerier(q), nil
 }
+
+func (wq *WrappedQuerier) Conn() *pgx.Conn {
+	return wq.QuerierTxWithTracing.Conn()
+}
+
+// LogRollback logs and performs a rollback if the transaction is still active
+func LogRollback(ctx context.Context, tx QuerierTx) {
+	if !isInTransaction(tx) {
+		return
+	}
+
+	log := logger.FromContext(ctx)
+	log.WarnContext(ctx, "transaction rollback called on an active transaction")
+
+	// if caller ctx is done we still need rollback to happen
+	// so Rollback gets a fresh context with span copied over
+	rbCtx := context.Background()
+	if span := trace.SpanFromContext(ctx); span != nil {
+		rbCtx = trace.ContextWithSpan(rbCtx, span)
+	}
+	if err := tx.Rollback(rbCtx); err != nil && !errors.Is(err, pgx.ErrTxClosed) {
+		log.ErrorContext(ctx, "rollback failed", "err", err)
+	}
+}
+
+func isInTransaction(tx QuerierTx) bool {
+	if tx == nil {
+		return false
+	}
+
+	conn := tx.Conn()
+	if conn == nil {
+		return false
+	}
+
+	// 'I' means idle, so if it's not idle, we're in a transaction
+	return conn.PgConn().TxStatus() != 'I'
+}