Control/defer sending out 201 status

Question

My controller code(implemented in python) first updates DB and then sends out 201 status code indicating it is done updating in DB. Issue is somebody waiting to fetch this update from DB will not work immediately because DB update takes some time(approximately 0.5 second) to come into effect.

Is there a way I can control/defer sending out 201? Any sample code/link will be appreciated.

Answer 1

I can suggest 2 options both of which would require your code to "wait" until it is sure that the data is now retrievable.

The first option would be to use time.sleep(). If you're sure you know how long the update to the database takes, you could hardcode a static wait time

time.sleep(0.5) # 1/2 a second pause

Disadvantage of this method is that wait time is hardcoded, so if the update takes a lot longer that the specified wait time, you run into the same problem again.

The second option would be to query for the written value immediately after writing to the database in a while loop and returning only when you successfully, read back the value you updated.

# Pseudocode
db.update(data)
while True:
    rdata = db.retrieve(id_for_data)
    if rdata.field == data.field:
        break
return response, http_code

Disadvantage of this method is that you could possibly wait a long time (or forever) if the db update takes a while (or even fails)