@@ -164,3 +164,30 @@ func Tail(src io.Reader, n int, dst *[]string) {

 		*dst = append(*dst, v.(string))

 	})

 }

+

+// AddEnv starts a new goroutine which will decode all subsequent data

+// as a stream of json-encoded objects, and point `dst` to the last

+// decoded object.

+// The result `env` can be queried using the type-neutral Env interface. 

+// It is not safe to query `env` until the Output is closed.

+func (o *Output) AddEnv() (dst *Env, err error) {

+	src, err := o.AddPipe()

+	if err != nil {

+		return nil, err

+	}

+	dst = &Env{}

+	o.tasks.Add(1)

+	go func() {

+		defer o.tasks.Done()

+		decoder := NewDecoder(src)

+		for {

+			env, err := decoder.Decode()

+			if err != nil {

+				return

+			}

+			*dst= *env

+		}

+	}()

+	return dst, nil

+}

+

@@ -72,6 +72,26 @@ func (w *sentinelWriteCloser) Close() error {

 	return nil

 }

+func TestOutputAddEnv(t *testing.T) {

+	input := "{\"foo\": \"bar\", \"answer_to_life_the_universe_and_everything\": 42}"

+	o := NewOutput()

+	result, err := o.AddEnv()

+	if err != nil {

+		t.Fatal(err)

+	}

+	o.Write([]byte(input))

+	o.Close()

+	if v := result.Get("foo"); v != "bar" {

+		t.Errorf("Expected %v, got %v", "bar", v)

+	}

+	if v := result.GetInt("answer_to_life_the_universe_and_everything"); v != 42 {

+		t.Errorf("Expected %v, got %v", 42, v)

+	}

+	if v := result.Get("this-value-doesnt-exist"); v != "" {

+		t.Errorf("Expected %v, got %v", "", v)

+	}

+}

+

 func TestOutputAddClose(t *testing.T) {

 	o := NewOutput()

 	var s sentinelWriteCloser