app.callbacks

[austinmw]

Hi, I'm able to run the first tutorial example in an AWS SageMaker notebook by modifying show_app and app as follows:

def show_app(app, port = 8000, 
             width = 800, 
             height = 500, 
             offline = True):
    
    def get_notebook_name():
        log_path = '/opt/ml/metadata/resource-metadata.json'
        with open(log_path, 'r') as logs:
            _logs = json.load(logs)
        return _logs['ResourceName']    

    url = f'https://{get_notebook_name().lower()}.notebook.us-east-1.sagemaker.aws/proxy/{port}'
        
    iframe = f'<a href="{url}" target="_new">Open in new window</a><hr><iframe src="{url}" width={width} height={height}></iframe>'    
    display.display_html(iframe, raw = True)
    if offline:
        app.css.config.serve_locally = True
        app.scripts.config.serve_locally = True
    return app.run_server(debug=False,
                          port=port)

app = dash.Dash(requests_pathname_prefix='/proxy/8000/')

However callbacks functionality doesn't seem to work. Is there any network settings I'm missing that would have to be modified for callbacks?

Here's a minimal non-working example:

app.layout = html.Div([
    dcc.Input(id='my-id', value='initial value', type="text"),
    html.Div(id='my-div')
])

@app.callback(
    Output(component_id='my-div', component_property='children'),
    [Input(component_id='my-id', component_property='value')],
)
def update_output_div(input_value):
    return 'You\'ve entered "{}"'.format(input_value)

Which results in this error:

Exception on /_dash-update-component [POST]
Traceback (most recent call last):
File "/home/ec2-user/anaconda3/envs/python3/lib/python3.6/site-packages/werkzeug/serving.py", line 124, in read_chunk_len
_len = int(line.strip(), 16)
ValueError: invalid literal for int() with base 16: '{"output":"my-div.children","outputs":{"id":"my-div","property":"children"},"inputs":[{"id":"my-id","property":"value","value":"initial value"}],"changedPropIds":[]}'