snmp: getting the short interface name instead of long ifDescr (again)

Question

I have a dash app where I added a JS code to print.window on button. The code works fine on each page of the multipage app and when printing multiple times on the page, but once I migrate back to a page I previously hit the button, it fails to work. Would this be a JS not executing problem? or something else? The code should execute 'on click', not on n_clicks count so nothing needs to be reset to zero. Thanks.

from dash import Dash, dcc, html, Input, Output, callback
import dash_bootstrap_components as dbc

app = Dash(__name__, suppress_callback_exceptions=True)

app.layout = html.Div([
    dcc.Location(id='url', refresh=False),
    html.Div(id='page-content')
])


index_page = html.Div([
    dcc.Link('Go to Page 1', href='/page-1'),
    html.Br(),
    dcc.Link('Go to Page 2', href='/page-2'),
])

page_1_layout = html.Div([
    html.H1('Page 1'),
    html.Div(id='hidden-content'),
    dbc.Button('Print', id='printing', color="#D3D3D3", outline=False, style={"background": "transparent",
                                                                              'color': 'grey',
                                                                              'border': '0px'},
               className="mr-1"),
    html.Div(id='page-1-content'),
    html.Br(),
    dcc.Link('Go to Page 2', href='/page-2'),
    html.Br(),
    dcc.Link('Go back to home', href='/'),
])

@callback(Output('page-1-content', 'children'),
              [Input('page-1-dropdown', 'value')])
def page_1_dropdown(value):
    return f'You have selected {value}'


page_2_layout = html.Div([
    html.H1('Page 2'),
    dbc.Button('Print', id='printing', color="#D3D3D3", outline=False, style={"background": "transparent",
                                                                              'color': 'grey',
                                                                              'border': '0px'},
               className="mr-1"),
    html.Div(id='page-2-content'),
    html.Br(),
    dcc.Link('Go to Page 1', href='/page-1'),
    html.Br(),
    dcc.Link('Go back to home', href='/')
])

@callback(Output('page-2-content', 'children'),
              [Input('page-2-radios', 'value')])
def page_2_radios(value):
    return f'You have selected {value}'


# Update the index
@callback(Output('page-content', 'children'),
              [Input('url', 'pathname')])
def display_page(pathname):
    if pathname == '/page-1':
        return page_1_layout
    elif pathname == '/page-2':
        return page_2_layout
    else:
        return index_page
    # You could also return a 404 "URL not found" page here


app.clientside_callback(
    """
(function() {
    registerPrintButtonHandler();
    return;

    function registerPrintButtonHandler() {
        var button = document.getElementById("printing");

        if (!button || button.onclick === onPrintButtonClick) {
            setTimeout(registerPrintButtonHandler, 500);
            return;
        }

        button.onclick = onPrintButtonClick;
    }

    function onPrintButtonClick() {
    {
    setTimeout(window.print, 700);
};
    }
})();
    """,
    Output('blank-output2', 'children'),
    Input('printing', 'value')
)

if __name__ == '__main__':
    app.run_server(debug=True)

Solution

It seems that using IF-MIB::ifDescr for the interface name is simply wrong. As the name of the OID implies, this is meant to be a (verbose) description ofthe interface, rather than a (unique) name.

The proper OID to use is IF-MIB::ifName

$ snmpwalk -Os -c public -v 1 wheezy 1.3.6.1.2.1.31.1.1.1.1
iso.3.6.1.2.1.31.1.1.1.1.1 = STRING: "lo"
iso.3.6.1.2.1.31.1.1.1.1.2 = STRING: "eth0"
iso.3.6.1.2.1.31.1.1.1.1.3 = STRING: "eth1"

$ snmpwalk -Os -c public -v 1 jessie 1.3.6.1.2.1.31.1.1.1.1
iso.3.6.1.2.1.31.1.1.1.1.1 = STRING: "lo"
iso.3.6.1.2.1.31.1.1.1.1.2 = STRING: "eth0"
iso.3.6.1.2.1.31.1.1.1.1.3 = STRING: "eth1"

In the case of cricket this means that i changed the cricket-configuration of the interface-map to:

OID    ifName                 1.3.6.1.2.1.31.1.1.1.1 

map interface-name
    base-oid    =   ifName
    match       =   %interface-name%

Comments

[emher]

Could you add a complete (i.e. runnable) MWE? That would ease reproduction/debugging of the issue.

[emher]

Also, could you elaborate on why you are not using Dash callback rather than doing JS event handling manually?

[Robert Marciniak]

Thank you for your help. I made a copy and paste functional MWE that seems to replicate my issue. Specifically, when I navigate from "home page" to page 1 and hit print, it works well, but when I nagivate "home" and back to page one I cannot get it to execute.

[Robert Marciniak]

As per your question: I believe print.window() functions cannot be executed with a Dash callback but necessitate either a client-side callback or JS file in the assetsf folder. But please correct me if I'm wrong.

[emher]

I just tested your code, and on my PC, the print popup is shown on every button click.

[Robert Marciniak]

I tried the code again in Safari and Chrome. Both replicated the failure. To clarify, the problem occurs going to page 1 -> back to home page and -> returning to page 1. The print function fails to execute. However, if I navigate from page 1-2 and back to page 1 it works fine. Quite bizarre