Polling in Karate based on JSON response [duplicate] - karate

Question

This question already has an answer here:
Karate framework retry until not working as expected
(1 answer)
Closed 2 years ago.
I am creating an animal into a database and then attempting to retrieve the animal which I have just created. However, there is a time lag ~5-10secs in the database. Therefore, a sleep wait is not suitable for this scenario as the response time varies. 
I would like to poll the message until animalId is returned in the array. It is also important that the requestId header is re-generated when the request is re-tried. 
What is the most elegant way of achieving this? 
Scenario:
Given path '/animals'
And header requestId = uniqueString(5)
When method post
Then status 200
* def animalId = response.animalId
Given path '/animals'
And header requestId = uniqueString(5)
When method get
Then status 200
{
"animals": [
{
"animalId": "12219958",
"reference": [
"12345"
]
}
]
}
* def animalDetails = karate.jsonPath (response, "$.animals.[?(#.reference[0]== '" + animalId + "' )]")[0]
* def animalId = '12345'

Answer 1

The retry until syntax is what you are looking for: https://github.com/intuit/karate#retry-until
EDIT: regarding this requirement:
It is also important that the requestId header is re-generated when the request is re-tried.
You have to configure headers with a JavaScript function, so that it is fired for each re-try. Otherwise there is no-other option to tweak the body, please manually write a polling loop if needed (also explained in the docs).
EDIT: here is a simple example to see for yourself how the foo header is dynamic for each re-try. Paste this in a fresh Scenario and it will work.
* def counter = { value: 0 }
* configure headers = function(){ return { foo: counter.value } }
* url 'http://httpbin.org/get'
* retry until counter.value++ == 2
* method get