vscode: Unable to load Tensorboard in Notebook

• Version: 1.50.0-insider
• OS: Darwin x64 19.6.0

Steps to Reproduce:

1. Run a Python notebook (using the new VS Code Notebook API) with the following cells:
   • Cell 1 %load_ext tensorboard
   • Cell 2

import tensorflow as tf
import datetime

mnist = tf.keras.datasets.mnist

(x_train, y_train),(x_test, y_test) = mnist.load_data()
x_train, x_test = x_train / 255.0, x_test / 255.0

def create_model():
  return tf.keras.models.Sequential([
    tf.keras.layers.Flatten(input_shape=(28, 28)),
    tf.keras.layers.Dense(512, activation='relu'),
    tf.keras.layers.Dropout(0.2),
    tf.keras.layers.Dense(10, activation='softmax')
  ])

model = create_model()
model.compile(optimizer='adam',
              loss='sparse_categorical_crossentropy',
              metrics=['accuracy'])

log_dir = "logs/fit/" + datetime.datetime.now().strftime("%Y%m%d-%H%M%S")
tensorboard_callback = tf.keras.callbacks.TensorBoard(log_dir=log_dir, histogram_freq=1)

model.fit(x=x_train, 
          y=y_train, 
          epochs=1, 
          validation_data=(x_test, y_test), 
          callbacks=[tensorboard_callback])

* Cell 3

%tensorboard --logdir logs/fit

1. At this point the last cell should have some empty output This is because the output attempts to display an iframe relative to the current home page. url = /:6060, this doesn’t work due to the custom resource schemes.

2. Verify the page http://localhost:6006 is accessible in a browser.

3. Add another cell with the following code:

from IPython.display import IFrame
IFrame('http://localhost:6006', width=700, height=350)

At this point it should display this iframe. But it doesn’t.

Here’s the output from VS Code when attempting to load the above page in the iframe:

webviewElement.ts:150 [Embedded Page] Refused to frame 'http://localhost:6006/' because an ancestor violates the following Content Security Policy directive: "frame-ancestors *".

Note: Another way to easily test this

• Run the python code outside VS Code (you don’t need Python extension)
• Create & open a simple notebook in VS Code, with HTML output in a cell:

<iframe
            width="700"
            height="350"
            src="http://localhost:6006"
            frameborder="0"
            allowfullscreen
        ></iframe>

Does this issue occur when all extensions are disabled?: N/A