Use generic environment variable function

cmd/app/app.go

@@ -8,7 +8,7 @@ import (
 
 func main() {
 	host := websupport.EnvironmentVariable("HOST", "")
-	port := websupport.IntegerEnvironmentVariable("PORT", 8777)
+	port := websupport.EnvironmentVariable("PORT", 8777)
 
 	server := websupport.NewServer(app.Handlers(true))
 

pkg/websupport/environment.go

@@ -5,20 +5,28 @@ import (
 	"strconv"
 )
 
-func EnvironmentVariable(variableName string, defaultValue string) string {
+type intOrString interface {
+	int | string
+}
+
+func EnvironmentVariable[T intOrString](variableName string, defaultValue T) T {
 	value, found := os.LookupEnv(variableName)
-	if found {
-		return value
-	} else {
+	if !found {
 		return defaultValue
 	}
-}
 
-func IntegerEnvironmentVariable(variableName string, defaultValue int) int {
-	value, err := strconv.Atoi(os.Getenv(variableName))
-	if err != nil {
-		return defaultValue
+	var result T
+
+	switch typedReference := any(&result).(type) {
+	case *string:
+		*typedReference = value
+	case *int:
+		i, err := strconv.Atoi(value)
+		if err != nil {
+			return defaultValue
+		}
+		*typedReference = i
 	}
 
-	return value
+	return result
 }

pkg/websupport/environment_test.go

@@ -0,0 +1,32 @@
+package websupport_test
+
+import (
+	"github.com/initialcapacity/go-streaming/pkg/websupport"
+	"github.com/stretchr/testify/assert"
+	"os"
+	"testing"
+)
+
+func set(t *testing.T, name, value string) {
+	err := os.Setenv(name, value)
+	assert.NoError(t, err)
+}
+
+func unset(t *testing.T, name string) {
+	err := os.Unsetenv(name)
+	assert.NoError(t, err)
+}
+
+func TestEnvironmentVariable(t *testing.T) {
+	set(t, "NOT_NUMBER", "hello")
+	set(t, "NUMBER", "39")
+	unset(t, "NOT_PRESENT")
+
+	assert.Equal(t, "hello", websupport.EnvironmentVariable("NOT_NUMBER", "pickles"))
+	assert.Equal(t, "39", websupport.EnvironmentVariable("NUMBER", "pickles"))
+	assert.Equal(t, "pickles", websupport.EnvironmentVariable("NOT_PRESENT", "pickles"))
+
+	assert.Equal(t, 867, websupport.EnvironmentVariable("NOT_NUMBER", 867))
+	assert.Equal(t, 39, websupport.EnvironmentVariable("NUMBER", 867))
+	assert.Equal(t, 867, websupport.EnvironmentVariable("NOT_PRESENT", 867))
+}