terraform: UIOutputPrefix

terraform/ui_output_prefix.go

@@ -0,0 +1,17 @@
+package terraform
+
+import (
+	"fmt"
+)
+
+// PrefixUIOutput is an implementation of UIOutput that prefixes the output
+// with a string.
+type PrefixUIOutput struct {
+	Prefix string
+	UIOutput     UIOutput
+}
+
+func (i *PrefixUIOutput) Output(v string) {
+	v = fmt.Sprintf("%s%s", i.Prefix, v)
+	i.UIOutput.Output(v)
+}

terraform/ui_output_prefix_test.go

@@ -0,0 +1,22 @@
+package terraform
+
+import (
+	"testing"
+)
+
+func TestPrefixUIOutput_impl(t *testing.T) {
+	var _ UIOutput = new(PrefixUIOutput)
+}
+
+func testPrefixUIOutput(t *testing.T) {
+	output := new(MockUIOutput)
+	prefix := &PrefixUIOutput{
+		Prefix:   "foo",
+		UIOutput: output,
+	}
+
+	prefix.Output("foo")
+	if output.OutputMessage != "foofoo" {
+		t.Fatalf("bad: %#v", output)
+	}
+}