fix(setup): use template for in_tx_order type (#9346)

# Which Problems Are Solved

Systems running with PostgreSQL before Zitadel v2.39 are likely to have
a wrong type for the `in_tx_order` column in the `eventstore.event2`
table. The migration at the time used the `event_sequence` as default
value without typecast, which results in a `bigint` type for that
column. However, when creating the table from scratch, we explicitly
specify the type to be `integer`.

Starting from Zitadel v2.67 we use a Pl/PgSQL function to push events.
The function requires the types from `eventstore.events2` to the same as
the `select` destinations used in the function. In the function
`in_tx_order` is also expected to by of `integer` type.

CochroachDB systems are not affected because `bigint` is an alias to the
`int` type. In other words, CockroachDB uses `int8` when specifying type
`int`. Therefore the types already match.

# How the Problems Are Solved

Retrieve the actual column type currently in use. A template is used to
assign the type to the `ordinality` column returned as `in_tx_order`.

# Additional Changes

- Detailed logging on migration failure

# Additional Context

- Closes #9180

---------

Co-authored-by: Silvan <27845747+adlerhurst@users.noreply.github.com>

cmd/setup/40.go

@@ -2,8 +2,13 @@ package setup
 
 import (
 	"context"
+	"database/sql"
 	"embed"
 	"fmt"
+	"io/fs"
+	"path"
+	"strings"
+	"text/template"
 
 	"github.com/zitadel/logging"
 
@@ -11,6 +16,13 @@ import (
 	"github.com/zitadel/zitadel/internal/eventstore"
 )
 
+// query filenames
+const (
+	fileInTxOrderType = "00_in_tx_order_type.sql"
+	fileType          = "01_type.sql"
+	fileFunc          = "02_func.sql"
+)
+
 var (
 	//go:embed 40/cockroach/*.sql
 	//go:embed 40/postgres/*.sql
@@ -22,10 +34,6 @@ type InitPushFunc struct {
 }
 
 func (mig *InitPushFunc) Execute(ctx context.Context, _ eventstore.Event) (err error) {
-	statements, err := readStatements(initPushFunc, "40", mig.dbClient.Type())
-	if err != nil {
-		return err
-	}
 	conn, err := mig.dbClient.Conn(ctx)
 	if err != nil {
 		return err
@@ -36,7 +44,10 @@ func (mig *InitPushFunc) Execute(ctx context.Context, _ eventstore.Event) (err e
 		// Force the pool to reopen connections to apply the new types
 		mig.dbClient.Pool.Reset()
 	}()
-
+	statements, err := mig.prepareStatements(ctx)
+	if err != nil {
+		return err
+	}
 	for _, stmt := range statements {
 		logging.WithFields("file", stmt.file, "migration", mig.String()).Info("execute statement")
 		if _, err := conn.ExecContext(ctx, stmt.query); err != nil {
@@ -50,3 +61,56 @@ func (mig *InitPushFunc) Execute(ctx context.Context, _ eventstore.Event) (err e
 func (mig *InitPushFunc) String() string {
 	return "40_init_push_func_v4"
 }
+
+func (mig *InitPushFunc) prepareStatements(ctx context.Context) ([]statement, error) {
+	funcTmpl, err := template.ParseFS(initPushFunc, mig.filePath(fileFunc))
+	if err != nil {
+		return nil, fmt.Errorf("prepare steps: %w", err)
+	}
+	typeName, err := mig.inTxOrderType(ctx)
+	if err != nil {
+		return nil, fmt.Errorf("prepare steps: %w", err)
+	}
+	var funcStep strings.Builder
+	err = funcTmpl.Execute(&funcStep, struct {
+		InTxOrderType string
+	}{
+		InTxOrderType: typeName,
+	})
+	if err != nil {
+		return nil, fmt.Errorf("prepare steps: %w", err)
+	}
+	typeStatement, err := fs.ReadFile(initPushFunc, mig.filePath(fileType))
+	if err != nil {
+		return nil, fmt.Errorf("prepare steps: %w", err)
+	}
+	return []statement{
+		{
+			file:  fileType,
+			query: string(typeStatement),
+		},
+		{
+			file:  fileFunc,
+			query: funcStep.String(),
+		},
+	}, nil
+}
+
+func (mig *InitPushFunc) inTxOrderType(ctx context.Context) (typeName string, err error) {
+	query, err := fs.ReadFile(initPushFunc, mig.filePath(fileInTxOrderType))
+	if err != nil {
+		return "", fmt.Errorf("get in_tx_order_type: %w", err)
+	}
+
+	err = mig.dbClient.QueryRowContext(ctx, func(row *sql.Row) error {
+		return row.Scan(&typeName)
+	}, string(query))
+	if err != nil {
+		return "", fmt.Errorf("get in_tx_order_type: %w", err)
+	}
+	return typeName, nil
+}
+
+func (mig *InitPushFunc) filePath(fileName string) string {
+	return path.Join("40", mig.dbClient.Type(), fileName)
+}