Add Before/After step

dbump.go

@@ -43,6 +43,13 @@ type Config struct {
 	// Going up does apply-revert-apply of each migration.
 	// Going down does revert-apply-revert of each migration.
 	ZigZag bool
+
+	// BeforeStep function will be invoked right before the DoStep for each step.
+	// Default is nil and means no-op.
+	BeforeStep func(ctx context.Context, step Step)
+	// AfterStep function will be invoked right after the DoStep for each step.
+	// Default is nil and means no-op.
+	AfterStep func(ctx context.Context, step Step)
 }
 
 // Migrator represents database over which we will run migrations.
@@ -120,6 +127,13 @@ func Run(ctx context.Context, config Config) error {
 		return fmt.Errorf("incorrect mode provided: %d", config.Mode)
 	}
 
+	if config.BeforeStep == nil {
+		config.BeforeStep = func(ctx context.Context, step Step) {}
+	}
+	if config.AfterStep == nil {
+		config.AfterStep = func(ctx context.Context, step Step) {}
+	}
+
 	m := mig{
 		Config:   config,
 		Migrator: config.Migrator,
@@ -203,9 +217,13 @@ func (m *mig) runMigrationsLocked(ctx context.Context, ms []*Migration) error {
 	}
 
 	for _, step := range m.prepareSteps(curr, target, ms) {
+		m.BeforeStep(ctx, step)
+
 		if err := m.DoStep(ctx, step); err != nil {
 			return err
 		}
+
+		m.AfterStep(ctx, step)
 	}
 	return nil
 }

dbump_test.go

@@ -3,6 +3,7 @@ package dbump
 import (
 	"context"
 	"errors"
+	"fmt"
 	"reflect"
 	"testing"
 )
@@ -230,6 +231,40 @@ func TestMigrateDrop(t *testing.T) {
 	mustEqual(t, mm.log, wantLog)
 }
 
+func TestBeforeAfterStep(t *testing.T) {
+	currVersion := 3
+	wantLog := []string{
+		"lockdb", "init", "getversion",
+		"before", "{v:4 q:'SELECT 4;' notx:false}",
+		"dostep", "{v:4 q:'SELECT 4;' notx:false}",
+		"after", "{v:4 q:'SELECT 4;' notx:false}",
+		"before", "{v:5 q:'SELECT 5;' notx:false}",
+		"dostep", "{v:5 q:'SELECT 5;' notx:false}",
+		"after", "{v:5 q:'SELECT 5;' notx:false}",
+		"unlockdb",
+	}
+
+	mm := &MockMigrator{
+		VersionFn: func(ctx context.Context) (version int, err error) {
+			return currVersion, nil
+		},
+	}
+	cfg := Config{
+		Migrator: mm,
+		Loader:   NewSliceLoader(testdataMigrations),
+		Mode:     ModeUp,
+		BeforeStep: func(ctx context.Context, step Step) {
+			mm.log = append(mm.log, "before", fmt.Sprintf("{v:%d q:'%s' notx:%v}", step.Version, step.Query, step.DisableTx))
+		},
+		AfterStep: func(ctx context.Context, step Step) {
+			mm.log = append(mm.log, "after", fmt.Sprintf("{v:%d q:'%s' notx:%v}", step.Version, step.Query, step.DisableTx))
+		},
+	}
+
+	failIfErr(t, Run(context.Background(), cfg))
+	mustEqual(t, mm.log, wantLog)
+}
+
 func TestLockless(t *testing.T) {
 	wantLog := []string{
 		"init",