chore: tidy up pkgs (#636)

for readability and towards potentially making helmfile usable as a go library

pkg/helmexec/context.go

@@ -0,0 +1,44 @@
+package helmexec
+
+import (
+	"os"
+	"path/filepath"
+)
+
+type HelmContext struct {
+	Tillerless      bool
+	TillerNamespace string
+	WorkerIndex     int
+}
+
+func (context *HelmContext) GetTillerlessArgs(helmBinary string) []string {
+	if context.Tillerless {
+		if context.TillerNamespace != "" {
+			return []string{"tiller", "run", context.TillerNamespace, "--", helmBinary}
+		} else {
+			return []string{"tiller", "run", "--", helmBinary}
+		}
+	} else {
+		return []string{}
+	}
+}
+
+func (context *HelmContext) getTillerlessEnv() map[string]string {
+	if context.Tillerless {
+		result := map[string]string{
+			"HELM_TILLER_SILENT": "true",
+			// Changing the TILLER port doesn't really work: https://github.com/helm/helm/issues/3159
+			// So this is not used for the moment.
+			// "HELM_TILLER_PORT":   strconv.Itoa(44134 + context.WorkerIndex),
+		}
+		if config := os.Getenv("KUBECONFIG"); config != "" {
+			absConfig, err := filepath.Abs(config)
+			if err == nil {
+				result["KUBECONFIG"] = absConfig
+			}
+		}
+		return result
+	} else {
+		return map[string]string{}
+	}
+}