v0.0.37

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  = 0
+	modeSourceFinished = 1
+	modeBufferReading  = 2
+	modeBufferFinished = 3
+)
 
 type BufferedReadCloser interface {
 	io.ReadCloser
 	BufferedAll() ([]byte, error)
+	Reset() error
 }
 
 type bufferedReadCloser struct {
-	buffer   []byte
-	inner    io.ReadCloser
-	finished bool
-}
-
-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
+	buffer []byte
+	inner  io.ReadCloser
+	mode   brcMode
+	off    int
 }
 
 func NewBufferedReadCloser(sub io.ReadCloser) BufferedReadCloser {
 	return &bufferedReadCloser{
-		buffer:   make([]byte, 0, 1024),
-		inner:    sub,
-		finished: false,
+		buffer: make([]byte, 0, 1024),
+		inner:  sub,
+		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()
-	if err != nil {
-		b.finished = true
+	switch b.mode {
+	case modeSourceReading:
+		_, err := b.BufferedAll()
+		if err != nil {
+			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")
 	}
-	return err
+
 }
 
 func (b *bufferedReadCloser) BufferedAll() ([]byte, error) {
-	arr := make([]byte, 1024)
-	for !b.finished {
-		_, err := b.Read(arr)
-		if err != nil && err != io.EOF {
-			return nil, err
+	switch b.mode {
+	case modeSourceReading:
+		arr := make([]byte, 1024)
+		for b.mode == modeSourceReading {
+			_, err := b.Read(arr)
+			if err != nil && err != io.EOF {
+				return nil, err
+			}
 		}
-	}
+		return b.buffer, nil
 
-	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")
+	}
 }