CODEWITHSUNDEEP
gogoogle-cloud-platformgoogle-cloud-datastoredeprecatedancestor
Grant Wilson
Grant Wilson

Reputation: 11

How to read from Datastore using an Ancestor query and latest golang libraries

I want to read all entities from a Datastore kind (around 6 entities/records).

I have a Datastore that is key'ed on a weird type that I am trying to understand. I can't find any uniqueness on the a key to perform a query on. The table looks like this: GCP Datastore representing data I want to read into my Go app

When I click on a record, it looks like this: Key literal exposed and used from here on out to try and get the records in the Go app

``I can perform an ancestor query in the console like this:``` GCP Datastore queried using Ancestor query

Great! So now I want to retrieve this data from my Golang App? But how? I see a lot of solutions online about using q.Get(...) // where q is a *Query struct Any of these solutions won't work because they import google.golang.org/appengine/datastore. I understand that this is legacy and deprecated. So I want a solution that imports cloud.google.com/go/datastore.

I tried something along these lines but didn't get much luck: First try using GetAll and query

I tried this next: Second try attempting to use ancestor query... not ready yet

Lastly I tried to get a single record directly: Lastly I tried to get the record directly

In all cases, my err is not nil and the dts that should be populated from datastore query is also nil.

Any guidance to help me understand how to query on this key type? Am I missing something fundamental with the way this table is key'ed and queried?

Thank you

Then I tried this:

Upvotes: 1

Views: 479

Answers (1)

James
James

Reputation: 749

It seems you are just missing your Namespace

// Merchant Struct
type MerchantDetails struct {
    MEID  string
    LinkTo *datastore.Key
    Title string
}

// Struct array to store in
var tokens []MerchantDetails

// Ancestor Key to filter by
parentKey := datastore.NameKey("A1_1113", "activate", nil)
parentKey.Namespace = "Devs1"

// The call using the new datastore UI. Basically query.Run(), but datastore.GetAll()
keys, err := helpers.DatastoreClient.GetAll(
    helpers.Ctx,
    datastore.NewQuery("A1_1112").Ancestor(parentKey).Namespace("Devs1"),
    &tokens,
)
if err != nil {
 return "", err
}

// Print all name/id from the found values
fmt.Printf("keys: %v", keys)

Upvotes: 1

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