Make INTERFACE optional with default wg0, document host networking, capabilities and name lookup

lib/environmentchecks/environmentchecks.go

@@ -1,27 +1,14 @@
 package environmentchecks
 
 import (
-	"fmt"
 	"os"
 )
 
+// HandleDefaults sets every env that is unset or empty to its default.
 func HandleDefaults(envDefaults map[string]string) {
 	for env, defaultValue := range envDefaults {
-		// Check if env is set
-		_, isSet := os.LookupEnv(env)
-		if !isSet {
+		if os.Getenv(env) == "" {
 			os.Setenv(env, defaultValue)
 		}
 	}
 }
-
-func HandleRequired(envRequired []string) error {
-	for _, env := range envRequired {
-		// Check if env is set
-		_, isSet := os.LookupEnv(env)
-		if !isSet {
-			return fmt.Errorf("env '%s' required, but not set", env)
-		}
-	}
-	return nil
-}

lib/environmentchecks/environmentchecks_test.go

@@ -0,0 +1,29 @@
+package environmentchecks
+
+import (
+	"os"
+	"testing"
+)
+
+func TestHandleDefaults(t *testing.T) {
+	t.Setenv("TEST_UNSET", "")
+	os.Unsetenv("TEST_UNSET")
+	t.Setenv("TEST_EMPTY", "")
+	t.Setenv("TEST_SET", "value")
+
+	HandleDefaults(map[string]string{
+		"TEST_UNSET": "default",
+		"TEST_EMPTY": "default",
+		"TEST_SET":   "default",
+	})
+
+	for env, want := range map[string]string{
+		"TEST_UNSET": "default",
+		"TEST_EMPTY": "default",
+		"TEST_SET":   "value",
+	} {
+		if got := os.Getenv(env); got != want {
+			t.Errorf("%s = %q, want %q", env, got, want)
+		}
+	}
+}