Save Tensorflow graph for viewing in Tensorboard without summary operations

You can also dump the graph as a GraphDef protobuf and load that directly in TensorBoard. You can do this without starting a session or running the model.

## ... create graph ...
>>> graph_def = tf.get_default_graph().as_graph_def()
>>> graphpb_txt = str(graph_def)
>>> with open('graphpb.txt', 'w') as f: f.write(graphpb_txt)

This will output a file that looks something like this, depending on the specifics of your model.

node {
  name: "W"
  op: "Const"
  attr {
    key: "dtype"
    value {
      type: DT_FLOAT
    }
  }
...
version 1

In TensorBoard you can then use the "Upload" button to load it from disk.

For efficiency, the tf.train.SummaryWriter logs asynchronously to disk. To ensure that the graph appears in the log, you must call close() or flush() on the writer before the program exits.