Datastore: Filtering with equality fails with FailedPrecondition desc = no matching index found

[lc-chrisbarton]

According to the docs:

https://cloud.google.com/datastore/docs/concepts/queries#datastore-equal-and-inequality-range-go
"Note that a query can combine equality (EQUAL) filters for different properties, along with one or more inequality filters on a single property. Thus the following is a valid query:"

query := datastore.NewQuery("Task").
    Filter("Priority =", 4).
    Filter("Done =", false).
    Filter("Created >", time.Date(1990, 1, 1, 0, 0, 0, 0, time.UTC)).
    Filter("Created <", time.Date(2000, 1, 1, 0, 0, 0, 0, time.UTC))

However when I create the simple table in the attached screenshot the following code from the docs fails:

q := datastore.NewQuery("Task").Namespace("test").
	Filter("Priority =", 4).
	Filter("Done =", false).
	Filter("Created >", time.Date(1990, 1, 1, 0, 0, 0, 0, time.UTC)).
	Filter("Created <", time.Date(2018, 3, 9, 0, 0, 0, 0, time.UTC))

var t []*task
if _, err := datastoreClient.GetAll(ctx, q, &t); err != nil {
	log.Printf("Failed reading: %v", err)
}

Error is:

2018/03/10 09:24:16 Failed reading: rpc error: code = FailedPrecondition desc = no matching index 
found. recommended index is:
- kind: Task
  properties:
  - name: Done
  - name: Priority
  - name: Created

[jba]

I think you'll need to define an index for that query. See https://cloud.google.com/datastore/docs/concepts/indexes#index_configuration.

[lc-chrisbarton]

Thanks very much!