v0.0.46

confext/confParser.go

@@ -0,0 +1,136 @@
+package confext
+
+import (
+	"errors"
+	"fmt"
+	"gogs.mikescher.com/BlackForestBytes/goext/timeext"
+	"math/bits"
+	"os"
+	"reflect"
+	"strconv"
+	"time"
+)
+
+// ApplyEnvOverrides overrides field values from environment variables
+//
+// fields must be tagged with `env:"env_key"`
+func ApplyEnvOverrides[T any](c *T) error {
+
+	rval := reflect.ValueOf(c).Elem()
+	rtyp := rval.Type()
+
+	for i := 0; i < rtyp.NumField(); i++ {
+
+		rsfield := rtyp.Field(i)
+		rvfield := rval.Field(i)
+
+		envkey := rsfield.Tag.Get("env")
+		if envkey == "" {
+			continue
+		}
+
+		envval, efound := os.LookupEnv(envkey)
+		if !efound {
+			continue
+		}
+
+		if rvfield.Type() == reflect.TypeOf("") {
+
+			rvfield.Set(reflect.ValueOf(envval))
+
+			fmt.Printf("[CONF] Overwrite config '%s' with '%s'\n", envkey, envval)
+
+		} else if rvfield.Type() == reflect.TypeOf(int(0)) {
+
+			envint, err := strconv.ParseInt(envval, 10, bits.UintSize)
+			if err != nil {
+				return errors.New(fmt.Sprintf("Failed to parse env-config variable '%s' to int (value := '%s')", envkey, envval))
+			}
+
+			rvfield.Set(reflect.ValueOf(int(envint)))
+
+			fmt.Printf("[CONF] Overwrite config '%s' with '%s'\n", envkey, envval)
+
+		} else if rvfield.Type() == reflect.TypeOf(int64(0)) {
+
+			envint, err := strconv.ParseInt(envval, 10, 64)
+			if err != nil {
+				return errors.New(fmt.Sprintf("Failed to parse env-config variable '%s' to int64 (value := '%s')", envkey, envval))
+			}
+
+			rvfield.Set(reflect.ValueOf(int64(envint)))
+
+			fmt.Printf("[CONF] Overwrite config '%s' with '%s'\n", envkey, envval)
+
+		} else if rvfield.Type() == reflect.TypeOf(int32(0)) {
+
+			envint, err := strconv.ParseInt(envval, 10, 32)
+			if err != nil {
+				return errors.New(fmt.Sprintf("Failed to parse env-config variable '%s' to int32 (value := '%s')", envkey, envval))
+			}
+
+			rvfield.Set(reflect.ValueOf(int32(envint)))
+
+			fmt.Printf("[CONF] Overwrite config '%s' with '%s'\n", envkey, envval)
+
+		} else if rvfield.Type() == reflect.TypeOf(int8(0)) {
+
+			envint, err := strconv.ParseInt(envval, 10, 8)
+			if err != nil {
+				return errors.New(fmt.Sprintf("Failed to parse env-config variable '%s' to int32 (value := '%s')", envkey, envval))
+			}
+
+			rvfield.Set(reflect.ValueOf(int8(envint)))
+
+			fmt.Printf("[CONF] Overwrite config '%s' with '%s'\n", envkey, envval)
+
+		} else if rvfield.Type() == reflect.TypeOf(time.Duration(0)) {
+
+			dur, err := timeext.ParseDurationShortString(envval)
+			if err != nil {
+				return errors.New(fmt.Sprintf("Failed to parse env-config variable '%s' to duration (value := '%s')", envkey, envval))
+			}
+
+			rvfield.Set(reflect.ValueOf(dur))
+
+			fmt.Printf("[CONF] Overwrite config '%s' with '%s'\n", envkey, dur.String())
+
+		} else if rvfield.Type() == reflect.TypeOf(time.UnixMilli(0)) {
+
+			tim, err := time.Parse(time.RFC3339Nano, envval)
+			if err != nil {
+				return errors.New(fmt.Sprintf("Failed to parse env-config variable '%s' to time.time (value := '%s')", envkey, envval))
+			}
+
+			rvfield.Set(reflect.ValueOf(tim))
+
+			fmt.Printf("[CONF] Overwrite config '%s' with '%s'\n", envkey, tim.String())
+
+		} else if rvfield.Type().ConvertibleTo(reflect.TypeOf(int(0))) {
+
+			envint, err := strconv.ParseInt(envval, 10, 8)
+			if err != nil {
+				return errors.New(fmt.Sprintf("Failed to parse env-config variable '%s' to <%s, ,int> (value := '%s')", rvfield.Type().Name(), envkey, envval))
+			}
+
+			envcvl := reflect.ValueOf(envint).Convert(rvfield.Type())
+
+			rvfield.Set(envcvl)
+
+			fmt.Printf("[CONF] Overwrite config '%s' with '%v'\n", envkey, envcvl.Interface())
+
+		} else if rvfield.Type().ConvertibleTo(reflect.TypeOf("")) {
+
+			envcvl := reflect.ValueOf(envval).Convert(rvfield.Type())
+
+			rvfield.Set(envcvl)
+
+			fmt.Printf("[CONF] Overwrite config '%s' with '%v'\n", envkey, envcvl.Interface())
+
+		} else {
+			return errors.New(fmt.Sprintf("Unknown kind/type in config: [ %s | %s ]", rvfield.Kind().String(), rvfield.Type().String()))
+		}
+	}
+
+	return nil
+}

confext/confParser_test.go

@@ -0,0 +1,116 @@
+package confext
+
+import (
+	"testing"
+	"time"
+)
+
+func TestApplyEnvOverridesNoop(t *testing.T) {
+
+	type aliasint int
+	type aliasstring string
+
+	type testdata struct {
+		V1 int           `env:"TEST_V1"`
+		VX string        ``
+		V2 string        `env:"TEST_V2"`
+		V3 int8          `env:"TEST_V3"`
+		V4 int32         `env:"TEST_V4"`
+		V5 int64         `env:"TEST_V5"`
+		V6 aliasint      `env:"TEST_V6"`
+		VY aliasint      ``
+		V7 aliasstring   `env:"TEST_V7"`
+		V8 time.Duration `env:"TEST_V8"`
+		V9 time.Time     `env:"TEST_V9"`
+	}
+
+	input := testdata{
+		V1: 1,
+		VX: "X",
+		V2: "2",
+		V3: 3,
+		V4: 4,
+		V5: 5,
+		V6: 6,
+		VY: 99,
+		V7: "7",
+		V8: 9,
+		V9: time.Unix(1671102873, 0),
+	}
+
+	output := input
+
+	err := ApplyEnvOverrides(&output)
+	if err != nil {
+		t.Errorf("%v", err)
+		t.FailNow()
+	}
+
+	assertEqual(t, input, output)
+}
+
+func TestApplyEnvOverridesSimple(t *testing.T) {
+
+	type aliasint int
+	type aliasstring string
+
+	type testdata struct {
+		V1 int           `env:"TEST_V1"`
+		VX string        ``
+		V2 string        `env:"TEST_V2"`
+		V3 int8          `env:"TEST_V3"`
+		V4 int32         `env:"TEST_V4"`
+		V5 int64         `env:"TEST_V5"`
+		V6 aliasint      `env:"TEST_V6"`
+		VY aliasint      ``
+		V7 aliasstring   `env:"TEST_V7"`
+		V8 time.Duration `env:"TEST_V8"`
+		V9 time.Time     `env:"TEST_V9"`
+	}
+
+	data := testdata{
+		V1: 1,
+		VX: "X",
+		V2: "2",
+		V3: 3,
+		V4: 4,
+		V5: 5,
+		V6: 6,
+		VY: 99,
+		V7: "7",
+		V8: 9,
+		V9: time.Unix(1671102873, 0),
+	}
+
+	t.Setenv("TEST_V1", "846")
+	t.Setenv("TEST_V2", "hello_world")
+	t.Setenv("TEST_V3", "6")
+	t.Setenv("TEST_V4", "333")
+	t.Setenv("TEST_V5", "-937")
+	t.Setenv("TEST_V6", "070")
+	t.Setenv("TEST_V7", "AAAAAA")
+	t.Setenv("TEST_V8", "1min4s")
+	t.Setenv("TEST_V9", "2009-11-10T23:00:00Z")
+
+	err := ApplyEnvOverrides(&data)
+	if err != nil {
+		t.Errorf("%v", err)
+		t.FailNow()
+	}
+
+	assertEqual(t, data.V1, 846)
+	assertEqual(t, data.V2, "hello_world")
+	assertEqual(t, data.V3, 6)
+	assertEqual(t, data.V4, 333)
+	assertEqual(t, data.V5, -937)
+	assertEqual(t, data.V6, 70)
+	assertEqual(t, data.V7, "AAAAAA")
+	assertEqual(t, data.V8, time.Second*64)
+	assertEqual(t, data.V9, time.Unix(1257894000, 0).UTC())
+}
+
+func assertEqual[T comparable](t *testing.T, actual T, expected T) {
+	if actual != expected {
+		t.Errorf("values differ: Actual: '%v', Expected: '%v'", actual, expected)
+	}
+}

dataext/bufferedReadCloser.go

@@ -1,56 +1,157 @@
 package dataext
 
-import "io"
+import (
+	"errors"
+	"io"
+)
+
+type brcMode int
+
+const (
+	modeSourceReading  brcMode = 0
+	modeSourceFinished brcMode = 1
+	modeBufferReading  brcMode = 2
+	modeBufferFinished brcMode = 3
+)
 
 type BufferedReadCloser interface {
 	io.ReadCloser
 	BufferedAll() ([]byte, error)
+	Reset() error
 }
 
 type bufferedReadCloser struct {
 	buffer []byte
 	inner  io.ReadCloser
-	finished bool
+	mode   brcMode
-}
+	off    int
-
-func (b *bufferedReadCloser) Read(p []byte) (int, error) {
-
-	n, err := b.inner.Read(p)
-	if n > 0 {
-		b.buffer = append(b.buffer, p[0:n]...)
-	}
-
-	if err == io.EOF {
-		b.finished = true
-	}
-
-	return n, err
 }
 
 func NewBufferedReadCloser(sub io.ReadCloser) BufferedReadCloser {
 	return &bufferedReadCloser{
 		buffer: make([]byte, 0, 1024),
 		inner:  sub,
-		finished: false,
+		mode:   modeSourceReading,
+		off:    0,
+	}
+}
+
+func (b *bufferedReadCloser) Read(p []byte) (int, error) {
+	switch b.mode {
+	case modeSourceReading:
+		n, err := b.inner.Read(p)
+		if n > 0 {
+			b.buffer = append(b.buffer, p[0:n]...)
+		}
+
+		if err == io.EOF {
+			b.mode = modeSourceFinished
+		}
+
+		return n, err
+
+	case modeSourceFinished:
+		return 0, io.EOF
+
+	case modeBufferReading:
+
+		if len(b.buffer) <= b.off {
+			b.mode = modeBufferFinished
+			if len(p) == 0 {
+				return 0, nil
+			}
+			return 0, io.EOF
+		}
+
+		n := copy(p, b.buffer[b.off:])
+		b.off += n
+		return n, nil
+
+	case modeBufferFinished:
+		return 0, io.EOF
+
+	default:
+		return 0, errors.New("object in undefined status")
 	}
 }
 
 func (b *bufferedReadCloser) Close() error {
-	err := b.inner.Close()
+	switch b.mode {
+	case modeSourceReading:
+		_, err := b.BufferedAll()
 		if err != nil {
-		b.finished = true
-	}
 			return err
 		}
+		err = b.inner.Close()
+		if err != nil {
+			return err
+		}
+		b.mode = modeSourceFinished
+		return nil
+
+	case modeSourceFinished:
+		return nil
+
+	case modeBufferReading:
+		b.mode = modeBufferFinished
+		return nil
+
+	case modeBufferFinished:
+		return nil
+
+	default:
+		return errors.New("object in undefined status")
+	}
+
+}
 
 func (b *bufferedReadCloser) BufferedAll() ([]byte, error) {
+	switch b.mode {
+	case modeSourceReading:
 		arr := make([]byte, 1024)
-	for !b.finished {
+		for b.mode == modeSourceReading {
 			_, err := b.Read(arr)
 			if err != nil && err != io.EOF {
 				return nil, err
 			}
 		}
-
 		return b.buffer, nil
+
+	case modeSourceFinished:
+		return b.buffer, nil
+
+	case modeBufferReading:
+		return b.buffer, nil
+
+	case modeBufferFinished:
+		return b.buffer, nil
+
+	default:
+		return nil, errors.New("object in undefined status")
+	}
+}
+
+func (b *bufferedReadCloser) Reset() error {
+	switch b.mode {
+	case modeSourceReading:
+		fallthrough
+	case modeSourceFinished:
+		err := b.Close()
+		if err != nil {
+			return err
+		}
+		b.mode = modeBufferReading
+		b.off = 0
+		return nil
+
+	case modeBufferReading:
+		fallthrough
+	case modeBufferFinished:
+		b.mode = modeBufferReading
+		b.off = 0
+		return nil
+
+	default:
+		return errors.New("object in undefined status")
+	}
 }

dataext/lruMap.go

@@ -19,40 +19,38 @@ import (
 // There are also a bunch of unit tests to ensure that the cache is always in a consistent state
 //
 
-type LRUData interface{}
+type LRUMap[TData any] struct {
-
-type LRUMap struct {
 	maxsize int
 	lock    sync.Mutex
 
-	cache map[string]*cacheNode
+	cache map[string]*cacheNode[TData]
 
-	lfuHead *cacheNode
+	lfuHead *cacheNode[TData]
-	lfuTail *cacheNode
+	lfuTail *cacheNode[TData]
 }
 
-type cacheNode struct {
+type cacheNode[TData any] struct {
 	key    string
-	data   LRUData
+	data   TData
-	parent *cacheNode
+	parent *cacheNode[TData]
-	child  *cacheNode
+	child  *cacheNode[TData]
 }
 
-func NewLRUMap(size int) *LRUMap {
+func NewLRUMap[TData any](size int) *LRUMap[TData] {
 	if size <= 2 && size != 0 {
 		panic("Size must be > 2  (or 0)")
 	}
 
-	return &LRUMap{
+	return &LRUMap[TData]{
 		maxsize: size,
 		lock:    sync.Mutex{},
-		cache:   make(map[string]*cacheNode, size+1),
+		cache:   make(map[string]*cacheNode[TData], size+1),
 		lfuHead: nil,
 		lfuTail: nil,
 	}
 }
 
-func (c *LRUMap) Put(key string, value LRUData) {
+func (c *LRUMap[TData]) Put(key string, value TData) {
 	if c.maxsize == 0 {
 		return // cache disabled
 	}
@@ -70,7 +68,7 @@ func (c *LRUMap) Put(key string, value LRUData) {
 	}
 
 	// key does not exist: insert into map and add to top of LFU
-	node = &cacheNode{
+	node = &cacheNode[TData]{
 		key:    key,
 		data:   value,
 		parent: nil,
@@ -95,9 +93,9 @@ func (c *LRUMap) Put(key string, value LRUData) {
 	}
 }
 
-func (c *LRUMap) TryGet(key string) (LRUData, bool) {
+func (c *LRUMap[TData]) TryGet(key string) (TData, bool) {
 	if c.maxsize == 0 {
-		return nil, false // cache disabled
+		return *new(TData), false // cache disabled
 	}
 
 	c.lock.Lock()
@@ -105,13 +103,13 @@ func (c *LRUMap) TryGet(key string) (LRUData, bool) {
 
 	val, ok := c.cache[key]
 	if !ok {
-		return nil, false
+		return *new(TData), false
 	}
 	c.moveNodeToTop(val)
 	return val.data, ok
 }
 
-func (c *LRUMap) moveNodeToTop(node *cacheNode) {
+func (c *LRUMap[TData]) moveNodeToTop(node *cacheNode[TData]) {
 	// (only called in critical section !)
 
 	if c.lfuHead == node { // fast case
@@ -144,7 +142,7 @@ func (c *LRUMap) moveNodeToTop(node *cacheNode) {
 	}
 }
 
-func (c *LRUMap) Size() int {
+func (c *LRUMap[TData]) Size() int {
 	c.lock.Lock()
 	defer c.lock.Unlock()
 	return len(c.cache)

dataext/lruMap_test.go

@@ -12,7 +12,7 @@ func init() {
 }
 
 func TestResultCache1(t *testing.T) {
-	cache := NewLRUMap(8)
+	cache := NewLRUMap[string](8)
 	verifyLRUList(cache, t)
 
 	key := randomKey()
@@ -39,7 +39,7 @@ func TestResultCache1(t *testing.T) {
 	if !ok {
 		t.Errorf("cache TryGet returned no value")
 	}
-	if !eq(cacheval, val) {
+	if cacheval != val {
 		t.Errorf("cache TryGet returned different value (%+v <> %+v)", cacheval, val)
 	}
 
@@ -50,7 +50,7 @@ func TestResultCache1(t *testing.T) {
 }
 
 func TestResultCache2(t *testing.T) {
-	cache := NewLRUMap(8)
+	cache := NewLRUMap[string](8)
 	verifyLRUList(cache, t)
 
 	key1 := "key1"
@@ -150,7 +150,7 @@ func TestResultCache2(t *testing.T) {
 }
 
 func TestResultCache3(t *testing.T) {
-	cache := NewLRUMap(8)
+	cache := NewLRUMap[string](8)
 	verifyLRUList(cache, t)
 
 	key1 := "key1"
@@ -160,20 +160,20 @@ func TestResultCache3(t *testing.T) {
 	cache.Put(key1, val1)
 	verifyLRUList(cache, t)
 
-	if val, ok := cache.TryGet(key1); !ok || !eq(val, val1) {
+	if val, ok := cache.TryGet(key1); !ok || val != val1 {
 		t.Errorf("Value in cache should be [val1]")
 	}
 
 	cache.Put(key1, val2)
 	verifyLRUList(cache, t)
 
-	if val, ok := cache.TryGet(key1); !ok || !eq(val, val2) {
+	if val, ok := cache.TryGet(key1); !ok || val != val2 {
 		t.Errorf("Value in cache should be [val2]")
 	}
 }
 
 // does a basic consistency check over the internal cache representation
-func verifyLRUList(cache *LRUMap, t *testing.T) {
+func verifyLRUList[TData any](cache *LRUMap[TData], t *testing.T) {
 	size := 0
 
 	tailFound := false
@@ -250,23 +250,10 @@ func randomKey() string {
 	return strconv.FormatInt(rand.Int63(), 16)
 }
 
-func randomVal() LRUData {
+func randomVal() string {
 	v, err := langext.NewHexUUID()
 	if err != nil {
 		panic(err)
 	}
-	return &v
+	return v
-}
-
-func eq(a LRUData, b LRUData) bool {
-	v1, ok1 := a.(*string)
-	v2, ok2 := b.(*string)
-	if ok1 && ok2 {
-		if v1 == nil || v2 == nil {
-			return false
-		}
-		return v1 == v2
-	}
-
-	return false
 }

dataext/syncSet.go

@@ -2,17 +2,17 @@ package dataext
 
 import "sync"
 
-type SyncStringSet struct {
+type SyncSet[TData comparable] struct {
-	data map[string]bool
+	data map[TData]bool
 	lock sync.Mutex
 }
 
-func (s *SyncStringSet) Add(value string) bool {
+func (s *SyncSet[TData]) Add(value TData) bool {
 	s.lock.Lock()
 	defer s.lock.Unlock()
 
 	if s.data == nil {
-		s.data = make(map[string]bool)
+		s.data = make(map[TData]bool)
 	}
 
 	_, ok := s.data[value]
@@ -21,12 +21,12 @@ func (s *SyncStringSet) Add(value string) bool {
 	return !ok
 }
 
-func (s *SyncStringSet) AddAll(values []string) {
+func (s *SyncSet[TData]) AddAll(values []TData) {
 	s.lock.Lock()
 	defer s.lock.Unlock()
 
 	if s.data == nil {
-		s.data = make(map[string]bool)
+		s.data = make(map[TData]bool)
 	}
 
 	for _, value := range values {
@@ -34,12 +34,12 @@ func (s *SyncStringSet) AddAll(values []string) {
 	}
 }
 
-func (s *SyncStringSet) Contains(value string) bool {
+func (s *SyncSet[TData]) Contains(value TData) bool {
 	s.lock.Lock()
 	defer s.lock.Unlock()
 
 	if s.data == nil {
-		s.data = make(map[string]bool)
+		s.data = make(map[TData]bool)
 	}
 
 	_, ok := s.data[value]
@@ -47,15 +47,15 @@ func (s *SyncStringSet) Contains(value string) bool {
 	return ok
 }
 
-func (s *SyncStringSet) Get() []string {
+func (s *SyncSet[TData]) Get() []TData {
 	s.lock.Lock()
 	defer s.lock.Unlock()
 
 	if s.data == nil {
-		s.data = make(map[string]bool)
+		s.data = make(map[TData]bool)
 	}
 
-	r := make([]string, 0, len(s.data))
+	r := make([]TData, 0, len(s.data))
 
 	for k := range s.data {
 		r = append(r, k)

langext/sort.go

@@ -0,0 +1,39 @@
+package langext
+
+import "sort"
+
+func Sort[T OrderedConstraint](arr []T) {
+	sort.Slice(arr, func(i1, i2 int) bool {
+		return arr[i1] < arr[i2]
+	})
+}
+
+func SortStable[T OrderedConstraint](arr []T) {
+	sort.SliceStable(arr, func(i1, i2 int) bool {
+		return arr[i1] < arr[i2]
+	})
+}
+
+func IsSorted[T OrderedConstraint](arr []T) bool {
+	return sort.SliceIsSorted(arr, func(i1, i2 int) bool {
+		return arr[i1] < arr[i2]
+	})
+}
+
+func SortSlice[T any](arr []T, less func(v1, v2 T) bool) {
+	sort.Slice(arr, func(i1, i2 int) bool {
+		return less(arr[i1], arr[i2])
+	})
+}
+
+func SortSliceStable[T any](arr []T, less func(v1, v2 T) bool) {
+	sort.SliceStable(arr, func(i1, i2 int) bool {
+		return less(arr[i1], arr[i2])
+	})
+}
+
+func IsSliceSorted[T any](arr []T, less func(v1, v2 T) bool) bool {
+	return sort.SliceIsSorted(arr, func(i1, i2 int) bool {
+		return less(arr[i1], arr[i2])
+	})
+}

sq/database.go

@@ -12,14 +12,15 @@ type DB interface {
 	Query(ctx context.Context, sql string, prep PP) (*sqlx.Rows, error)
 	Ping(ctx context.Context) error
 	BeginTransaction(ctx context.Context, iso sql.IsolationLevel) (Tx, error)
-	SetListener(listener Listener)
+	AddListener(listener Listener)
+	Exit() error
 }
 
 type database struct {
 	db    *sqlx.DB
 	txctr uint16
 	lock  sync.Mutex
-	lstr  Listener
+	lstr  []Listener
 }
 
 func NewDB(db *sqlx.DB) DB {
@@ -27,31 +28,50 @@ func NewDB(db *sqlx.DB) DB {
 		db:    db,
 		txctr: 0,
 		lock:  sync.Mutex{},
+		lstr:  make([]Listener, 0),
 	}
 }
 
-func (db *database) SetListener(listener Listener) {
+func (db *database) AddListener(listener Listener) {
-	db.lstr = listener
+	db.lstr = append(db.lstr, listener)
 }
 
-func (db *database) Exec(ctx context.Context, sql string, prep PP) (sql.Result, error) {
+func (db *database) Exec(ctx context.Context, sqlstr string, prep PP) (sql.Result, error) {
-	if db.lstr != nil {
+	origsql := sqlstr
-		db.lstr.OnExec(nil, sql, &prep)
+	for _, v := range db.lstr {
+		err := v.PreExec(ctx, nil, &sqlstr, &prep)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	res, err := db.db.NamedExecContext(ctx, sqlstr, prep)
+
+	for _, v := range db.lstr {
+		v.PostExec(nil, origsql, sqlstr, prep)
 	}
 
-	res, err := db.db.NamedExecContext(ctx, sql, prep)
 	if err != nil {
 		return nil, err
 	}
 	return res, nil
 }
 
-func (db *database) Query(ctx context.Context, sql string, prep PP) (*sqlx.Rows, error) {
+func (db *database) Query(ctx context.Context, sqlstr string, prep PP) (*sqlx.Rows, error) {
-	if db.lstr != nil {
+	origsql := sqlstr
-		db.lstr.OnQuery(nil, sql, &prep)
+	for _, v := range db.lstr {
+		err := v.PreQuery(ctx, nil, &sqlstr, &prep)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	rows, err := sqlx.NamedQueryContext(ctx, db.db, sqlstr, prep)
+
+	for _, v := range db.lstr {
+		v.PostQuery(nil, origsql, sqlstr, prep)
 	}
 
-	rows, err := db.db.NamedQueryContext(ctx, sql, prep)
 	if err != nil {
 		return nil, err
 	}
@@ -59,11 +79,19 @@ func (db *database) Query(ctx context.Context, sql string, prep PP) (*sqlx.Rows,
 }
 
 func (db *database) Ping(ctx context.Context) error {
-	if db.lstr != nil {
+	for _, v := range db.lstr {
-		db.lstr.OnPing()
+		err := v.PrePing(ctx)
+		if err != nil {
+			return err
+		}
 	}
 
 	err := db.db.PingContext(ctx)
+
+	for _, v := range db.lstr {
+		v.PostPing(err)
+	}
+
 	if err != nil {
 		return err
 	}
@@ -76,8 +104,11 @@ func (db *database) BeginTransaction(ctx context.Context, iso sql.IsolationLevel
 	db.txctr += 1 // with overflow !
 	db.lock.Unlock()
 
-	if db.lstr != nil {
+	for _, v := range db.lstr {
-		db.lstr.OnTxBegin(txid)
+		err := v.PreTxBegin(ctx, txid)
+		if err != nil {
+			return nil, err
+		}
 	}
 
 	xtx, err := db.db.BeginTxx(ctx, &sql.TxOptions{Isolation: iso})
@@ -85,5 +116,13 @@ func (db *database) BeginTransaction(ctx context.Context, iso sql.IsolationLevel
 		return nil, err
 	}
 
+	for _, v := range db.lstr {
+		v.PostTxBegin(txid, err)
+	}
+
 	return NewTransaction(xtx, txid, db.lstr), nil
 }
+
+func (db *database) Exit() error {
+	return db.db.Close()
+}

sq/listener.go

@@ -1,10 +1,19 @@
 package sq
 
+import "context"
+
 type Listener interface {
-	OnQuery(txID *uint16, sql string, params *PP)
+	PrePing(ctx context.Context) error
-	OnExec(txID *uint16, sql string, params *PP)
+	PreTxBegin(ctx context.Context, txid uint16) error
-	OnPing()
+	PreTxCommit(txid uint16) error
-	OnTxBegin(txid uint16)
+	PreTxRollback(txid uint16) error
-	OnTxCommit(txid uint16)
+	PreQuery(ctx context.Context, txID *uint16, sql *string, params *PP) error
-	OnTxRollback(txid uint16)
+	PreExec(ctx context.Context, txID *uint16, sql *string, params *PP) error
+
+	PostPing(result error)
+	PostTxBegin(txid uint16, result error)
+	PostTxCommit(txid uint16, result error)
+	PostTxRollback(txid uint16, result error)
+	PostQuery(txID *uint16, sqlOriginal string, sqlReal string, params PP)
+	PostExec(txID *uint16, sqlOriginal string, sqlReal string, params PP)
 }

sq/scanner.go

@@ -6,24 +6,79 @@ import (
 	"github.com/jmoiron/sqlx"
 )
 
-func ScanSingle[TData any](rows *sqlx.Rows, close bool) (TData, error) {
+type StructScanMode string
+
+const (
+	SModeFast     StructScanMode = "FAST"
+	SModeExtended StructScanMode = "EXTENDED"
+)
+
+type StructScanSafety string
+
+const (
+	Safe   StructScanSafety = "SAFE"
+	Unsafe StructScanSafety = "UNSAFE"
+)
+
+func ScanSingle[TData any](rows *sqlx.Rows, mode StructScanMode, sec StructScanSafety, close bool) (TData, error) {
 	if rows.Next() {
+		var strscan *StructScanner
+
+		if sec == Safe {
+			strscan = NewStructScanner(rows, false)
 			var data TData
-		err := rows.StructScan(&data)
+			err := strscan.Start(&data)
 			if err != nil {
 				return *new(TData), err
 			}
+		} else if sec == Unsafe {
+			strscan = NewStructScanner(rows, true)
+			var data TData
+			err := strscan.Start(&data)
+			if err != nil {
+				return *new(TData), err
+			}
+		} else {
+			return *new(TData), errors.New("unknown value for <sec>")
+		}
+
+		var data TData
+
+		if mode == SModeFast {
+			err := strscan.StructScanBase(&data)
+			if err != nil {
+				return *new(TData), err
+			}
+		} else if mode == SModeExtended {
+			var data TData
+			err := strscan.StructScanExt(&data)
+			if err != nil {
+				return *new(TData), err
+			}
+		} else {
+			return *new(TData), errors.New("unknown value for <mode>")
+		}
+
 		if rows.Next() {
-			_ = rows.Close()
-			return *new(TData), errors.New("sql returned more than onw row")
-		}
 			if close {
-			err = rows.Close()
+				_ = rows.Close()
+			}
+			return *new(TData), errors.New("sql returned more than one row")
+		}
+
+		if close {
+			err := rows.Close()
 			if err != nil {
 				return *new(TData), err
 			}
 		}
+
+		if err := rows.Err(); err != nil {
+			return *new(TData), err
+		}
+
 		return data, nil
+
 	} else {
 		if close {
 			_ = rows.Close()
@@ -32,21 +87,55 @@ func ScanSingle[TData any](rows *sqlx.Rows, close bool) (TData, error) {
 	}
 }
 
-func ScanAll[TData any](rows *sqlx.Rows, close bool) ([]TData, error) {
+func ScanAll[TData any](rows *sqlx.Rows, mode StructScanMode, sec StructScanSafety, close bool) ([]TData, error) {
+	var strscan *StructScanner
+
+	if sec == Safe {
+		strscan = NewStructScanner(rows, false)
+		var data TData
+		err := strscan.Start(&data)
+		if err != nil {
+			return nil, err
+		}
+	} else if sec == Unsafe {
+		strscan = NewStructScanner(rows, true)
+		var data TData
+		err := strscan.Start(&data)
+		if err != nil {
+			return nil, err
+		}
+	} else {
+		return nil, errors.New("unknown value for <sec>")
+	}
+
 	res := make([]TData, 0)
 	for rows.Next() {
+		if mode == SModeFast {
 			var data TData
-		err := rows.StructScan(&data)
+			err := strscan.StructScanBase(&data)
 			if err != nil {
 				return nil, err
 			}
 			res = append(res, data)
+		} else if mode == SModeExtended {
+			var data TData
+			err := strscan.StructScanExt(&data)
+			if err != nil {
+				return nil, err
+			}
+			res = append(res, data)
+		} else {
+			return nil, errors.New("unknown value for <mode>")
+		}
 	}
 	if close {
-		err := rows.Close()
+		err := strscan.rows.Close()
 		if err != nil {
 			return nil, err
 		}
 	}
+	if err := rows.Err(); err != nil {
+		return nil, err
+	}
 	return res, nil
 }

sq/structscanner.go

@@ -0,0 +1,223 @@
+package sq
+
+import (
+	"errors"
+	"fmt"
+	"github.com/jmoiron/sqlx"
+	"github.com/jmoiron/sqlx/reflectx"
+	"reflect"
+)
+
+// forked from sqlx, but added ability to unmarshal optional-nested structs
+
+type StructScanner struct {
+	rows   *sqlx.Rows
+	Mapper *reflectx.Mapper
+	unsafe bool
+
+	fields  [][]int
+	values  []any
+	columns []string
+}
+
+func NewStructScanner(rows *sqlx.Rows, unsafe bool) *StructScanner {
+	return &StructScanner{
+		rows:   rows,
+		Mapper: reflectx.NewMapper("db"),
+		unsafe: unsafe,
+	}
+}
+
+func (r *StructScanner) Start(dest any) error {
+	v := reflect.ValueOf(dest)
+
+	if v.Kind() != reflect.Ptr {
+		return errors.New("must pass a pointer, not a value, to StructScan destination")
+	}
+
+	columns, err := r.rows.Columns()
+	if err != nil {
+		return err
+	}
+
+	r.columns = columns
+	r.fields = r.Mapper.TraversalsByName(v.Type(), columns)
+	// if we are not unsafe and are missing fields, return an error
+	if f, err := missingFields(r.fields); err != nil && !r.unsafe {
+		return fmt.Errorf("missing destination name %s in %T", columns[f], dest)
+	}
+	r.values = make([]interface{}, len(columns))
+
+	return nil
+}
+
+// StructScan forked from github.com/jmoiron/sqlx@v1.3.5/sqlx.go
+// does also wok with nullabel structs (from LEFT JOIN's)
+func (r *StructScanner) StructScanExt(dest any) error {
+	v := reflect.ValueOf(dest)
+
+	if v.Kind() != reflect.Ptr {
+		return errors.New("must pass a pointer, not a value, to StructScan destination")
+	}
+
+	// ========= STEP 1 ::  =========
+
+	v = v.Elem()
+
+	err := fieldsByTraversalExtended(v, r.fields, r.values)
+	if err != nil {
+		return err
+	}
+	// scan into the struct field pointers and append to our results
+	err = r.rows.Scan(r.values...)
+	if err != nil {
+		return err
+	}
+
+	nullStructs := make(map[string]bool)
+
+	for i, traversal := range r.fields {
+		if len(traversal) == 0 {
+			continue
+		}
+
+		isnsil := reflect.ValueOf(r.values[i]).Elem().IsNil()
+
+		for i := 1; i < len(traversal); i++ {
+
+			canParentNil := reflectx.FieldByIndexes(v, traversal[0:i]).Kind() == reflect.Pointer
+
+			k := fmt.Sprintf("%v", traversal[0:i])
+			if v, ok := nullStructs[k]; ok {
+
+				nullStructs[k] = canParentNil && v && isnsil
+
+			} else {
+				nullStructs[k] = canParentNil && isnsil
+			}
+		}
+
+	}
+
+	forcenulled := make(map[string]bool)
+
+	for i, traversal := range r.fields {
+		if len(traversal) == 0 {
+			continue
+		}
+
+		anyparentnull := false
+		for i := 1; i < len(traversal); i++ {
+			k := fmt.Sprintf("%v", traversal[0:i])
+			if nv, ok := nullStructs[k]; ok && nv {
+
+				if _, ok := forcenulled[k]; !ok {
+					f := reflectx.FieldByIndexes(v, traversal[0:i])
+					f.Set(reflect.New(f.Type().Elem())) // set to nil
+					forcenulled[k] = true
+				}
+
+				anyparentnull = true
+				break
+
+			}
+		}
+
+		if anyparentnull {
+			continue
+		}
+
+		f := reflectx.FieldByIndexes(v, traversal)
+
+		val1 := reflect.ValueOf(r.values[i])
+		val2 := val1.Elem()
+		val3 := val2.Elem()
+
+		if val2.IsNil() {
+			if f.Kind() != reflect.Pointer {
+				return errors.New(fmt.Sprintf("Cannot set field %v to NULL value from column '%s' (type: %s)", traversal, r.columns[i], f.Type().String()))
+			}
+
+			f.Set(reflect.New(f.Type().Elem())) // set to nil
+		} else {
+			f.Set(val3)
+		}
+
+	}
+
+	return r.rows.Err()
+}
+
+// StructScan forked from github.com/jmoiron/sqlx@v1.3.5/sqlx.go
+// without (relevant) changes
+func (r *StructScanner) StructScanBase(dest any) error {
+	v := reflect.ValueOf(dest)
+
+	if v.Kind() != reflect.Ptr {
+		return errors.New("must pass a pointer, not a value, to StructScan destination")
+	}
+
+	v = v.Elem()
+
+	err := fieldsByTraversalBase(v, r.fields, r.values, true)
+	if err != nil {
+		return err
+	}
+	// scan into the struct field pointers and append to our results
+	err = r.rows.Scan(r.values...)
+	if err != nil {
+		return err
+	}
+	return r.rows.Err()
+}
+
+// fieldsByTraversal forked from github.com/jmoiron/sqlx@v1.3.5/sqlx.go
+func fieldsByTraversalExtended(v reflect.Value, traversals [][]int, values []interface{}) error {
+	v = reflect.Indirect(v)
+	if v.Kind() != reflect.Struct {
+		return errors.New("argument not a struct")
+	}
+
+	for i, traversal := range traversals {
+		if len(traversal) == 0 {
+			values[i] = new(interface{})
+			continue
+		}
+		f := reflectx.FieldByIndexes(v, traversal)
+
+		values[i] = reflect.New(reflect.PointerTo(f.Type())).Interface()
+	}
+	return nil
+}
+
+// fieldsByTraversal forked from github.com/jmoiron/sqlx@v1.3.5/sqlx.go
+func fieldsByTraversalBase(v reflect.Value, traversals [][]int, values []interface{}, ptrs bool) error {
+	v = reflect.Indirect(v)
+	if v.Kind() != reflect.Struct {
+		return errors.New("argument not a struct")
+	}
+
+	for i, traversal := range traversals {
+		if len(traversal) == 0 {
+			values[i] = new(interface{})
+			continue
+		}
+		f := reflectx.FieldByIndexes(v, traversal)
+		if ptrs {
+			values[i] = f.Addr().Interface()
+		} else {
+			values[i] = f.Interface()
+		}
+	}
+	return nil
+}
+
+// missingFields forked from github.com/jmoiron/sqlx@v1.3.5/sqlx.go
+func missingFields(transversals [][]int) (field int, err error) {
+	for i, t := range transversals {
+		if len(t) == 0 {
+			return i, errors.New("missing field")
+		}
+	}
+	return 0, nil
+}

sq/transaction.go

@@ -17,10 +17,10 @@ type Tx interface {
 type transaction struct {
 	tx   *sqlx.Tx
 	id   uint16
-	lstr Listener
+	lstr []Listener
 }
 
-func NewTransaction(xtx *sqlx.Tx, txid uint16, lstr Listener) Tx {
+func NewTransaction(xtx *sqlx.Tx, txid uint16, lstr []Listener) Tx {
 	return &transaction{
 		tx:   xtx,
 		id:   txid,
@@ -29,39 +29,75 @@ func NewTransaction(xtx *sqlx.Tx, txid uint16, lstr Listener) Tx {
 }
 
 func (tx *transaction) Rollback() error {
-	if tx.lstr != nil {
+	for _, v := range tx.lstr {
-		tx.lstr.OnTxRollback(tx.id)
+		err := v.PreTxRollback(tx.id)
+		if err != nil {
+			return err
+		}
 	}
 
-	return tx.tx.Rollback()
+	result := tx.tx.Rollback()
+
+	for _, v := range tx.lstr {
+		v.PostTxRollback(tx.id, result)
+	}
+
+	return result
 }
 
 func (tx *transaction) Commit() error {
-	if tx.lstr != nil {
+	for _, v := range tx.lstr {
-		tx.lstr.OnTxCommit(tx.id)
+		err := v.PreTxCommit(tx.id)
+		if err != nil {
+			return err
+		}
 	}
 
-	return tx.tx.Commit()
+	result := tx.tx.Commit()
+
+	for _, v := range tx.lstr {
+		v.PostTxRollback(tx.id, result)
 	}
 
-func (tx *transaction) Exec(ctx context.Context, sql string, prep PP) (sql.Result, error) {
+	return result
-	if tx.lstr != nil {
+}
-		tx.lstr.OnExec(langext.Ptr(tx.id), sql, &prep)
+
+func (tx *transaction) Exec(ctx context.Context, sqlstr string, prep PP) (sql.Result, error) {
+	origsql := sqlstr
+	for _, v := range tx.lstr {
+		err := v.PreExec(ctx, langext.Ptr(tx.id), &sqlstr, &prep)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	res, err := tx.tx.NamedExecContext(ctx, sqlstr, prep)
+
+	for _, v := range tx.lstr {
+		v.PostExec(langext.Ptr(tx.id), origsql, sqlstr, prep)
 	}
 
-	res, err := tx.tx.NamedExecContext(ctx, sql, prep)
 	if err != nil {
 		return nil, err
 	}
 	return res, nil
 }
 
-func (tx *transaction) Query(ctx context.Context, sql string, prep PP) (*sqlx.Rows, error) {
+func (tx *transaction) Query(ctx context.Context, sqlstr string, prep PP) (*sqlx.Rows, error) {
-	if tx.lstr != nil {
+	origsql := sqlstr
-		tx.lstr.OnQuery(langext.Ptr(tx.id), sql, &prep)
+	for _, v := range tx.lstr {
+		err := v.PreQuery(ctx, langext.Ptr(tx.id), &sqlstr, &prep)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	rows, err := sqlx.NamedQueryContext(ctx, tx.tx, sqlstr, prep)
+
+	for _, v := range tx.lstr {
+		v.PostQuery(langext.Ptr(tx.id), origsql, sqlstr, prep)
 	}
 
-	rows, err := sqlx.NamedQueryContext(ctx, tx.tx, sql, prep)
 	if err != nil {
 		return nil, err
 	}