Before an app is deployed to Dash Enterprise, a check is performed to make sure that
the app is functional. The default check will test to see if the app has encountered a fatal error
in the first 10 seconds of running.
It is possible to customize the health checks performed on your app by adding a file named
the root directory of your app. In this file you can specify Checks Settings to instruct Dash Enterprise when
and how to perform the checks. You can also configure Checks Instructions to tell Dash Enterprise what endpoints to
test and what content it should find there.
You can specify values for
ATTEMPTS to set the period of time
that Dash Enterprise waits before performing the check, the amount of time before it times out, and the number of times
it will run them before determining that the deployment failed.
In the example
CHECKS file below, Dash Enterprise will wait 15 seconds before performing the check, allow up to 10 seconds
for a response from the app and perform the check 3 times before marking it as a failure.
The instructions are specified in the format of a relative link followed by content that Dash Enterprise
should find in the response. The expected content can be omitted if text content doesn’t make sense (e.g if
you want to check whether an image can be served). The example below checks the layout for the text
_dash-undo-redo is included in the dash.css file and that dash-logo.png is being served by the app.