Things I Learned: Google App Engine Django Platform Search Index Updates

Let's say you have a deployed Google App Engine application you've been using for years like the ham radio practice exams we're updating here. You decide to output data the app is obviously using all the time. For us, it was the table of help topic links for each exam question. You think you're going to output the data easily, and then:

NeedIndexError: no matching index found. recommended index is

and nothing.

This happened here today, (obviously right?) I had to walk through a series of documentation steps and log messages, but the answer in the end was simple.

First, the message above doesn't turn up in your app, it turn up in your log message explorer. For us, that's at

https://console.cloud.google.com/logs/query;cursorTimestamp=2023-07-03T15:57:44.595552Z?project=hamdaise

Next, that's where you'll find an actually very handy error message with this at the bottom (your data model will be different unless you forked the ham radio exam repo.)

That's the hint that tells you to look in your app's index.yaml file. But don't just look there, actually add the suggestion to the file. Then redeploy so the file is sent to your app on Google App Engine. Then, you're not done.

For your last step, run this command using gcloud:

gcloud datastore indexes create index.yaml

Then, just to be sure you did everything correclty, check for your new index at:

https://console.cloud.google.com/datastore/databases/-default-/indexes?project=hamdaise

(adapted for your app of course)

You'll see something like

It will take a minute or two (literally) for the green checkmark to appear next to your new index. After that, things should work again.

References:

Practice Exams

AppEngine index update instructions

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