feat: add MustHaveValue helper

extutil/extutil.go

@@ -8,6 +8,7 @@ package extutil
 import (
 	"fmt"
 	"github.com/steadybit/extension-kit/extconversion"
+	"reflect"
 	"strconv"
 	"strings"
 )
@@ -170,6 +171,30 @@ func ToUInt(val interface{}) uint {
 	}
 }
 
+type Measurable[T any, K comparable] interface {
+	~string | ~[]T | ~map[K]T | ~chan T
+}
+
+// MustHaveValue panics if the given key is not present in the map or the value is nil or empty.
+func MustHaveValue[T any, K comparable](m map[K]T, key K) T {
+	val, ok := m[key]
+	if !ok {
+		panic(fmt.Sprintf("missing value for %v", key))
+	}
+
+	kind := reflect.TypeOf(val).Kind()
+	if kind == reflect.Array || kind == reflect.Chan || kind == reflect.Map || kind == reflect.Slice || kind == reflect.String {
+		if reflect.ValueOf(val).Len() == 0 {
+			panic(fmt.Sprintf("value for %v is %v ", key, val))
+		}
+	} else if kind == reflect.Ptr {
+		if reflect.ValueOf(val).IsNil() {
+			panic(fmt.Sprintf("value for %v is nil ", key))
+		}
+	}
+	return val
+}
+
 func ToStringArray(s interface{}) []string {
 	if s == nil {
 		return nil

extutil/extutil_test.go

@@ -1,6 +1,7 @@
 package extutil
 
 import (
+	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 	"testing"
 )
@@ -237,3 +238,25 @@ func TestMaskString(t *testing.T) {
 		})
 	}
 }
+
+func TestMustHaveValue(t *testing.T) {
+	assert.Equal(t, 0, MustHaveValue(map[string]int{"key": 0}, "key"))
+	assert.Panics(t, func() {
+		MustHaveValue(map[string]int{"key": 0}, "missing")
+	})
+
+	assert.Equal(t, "value", MustHaveValue(map[string]string{"key": "value"}, "key"))
+	assert.Panics(t, func() {
+		MustHaveValue(map[string]string{"key": "value"}, "missing")
+	})
+
+	assert.Equal(t, Ptr("value"), MustHaveValue(map[string]*string{"key": Ptr("value")}, "key"))
+	assert.Panics(t, func() {
+		MustHaveValue(map[string]*string{"empty": nil}, "empty")
+	})
+
+	assert.Equal(t, []string{"value"}, MustHaveValue(map[string][]string{"key": {"value"}}, "key"))
+	assert.Panics(t, func() {
+		MustHaveValue(map[string][]string{"empty": {}}, "empty")
+	})
+}