Hi,
Im trying to get DataLoader working with an external service.
This is my field resolver
object :recent_conversation do
# other fields here
field :sender, non_null(:user), description: "Last sender for the conversation" do
resolve fn %{sender_id: sender_id}, _args, %{context: %{loader: loader}} ->
loader
|> Dataloader.load(:user, :user, sender_id)
|> Dataloader.run()
|> on_load(fn loader ->
loader
|> Dataloader.get(:user, :user, sender_id)
|> case do
%{} = user ->
{:ok, user}
end
end)
end
end
end
And here is my dataloder KV source
def data() do
Dataloader.KV.new(&fetch/2)
end
def fetch(_batch_key, users) do
IO.puts("here")
IO.inspect(users)
loaded_users = users |> MapSet.to_list() |> load_users()
users
|> Enum.with_index()
|> Enum.reduce(%{}, fn {id, idx}, results ->
Map.put(results, id, Enum.at(loaded_users, idx))
end)
end
defp load_users(ids) when is_list(ids) do
IO.puts("Loading users #{inspect(ids)}")
case ApiClient.get_users_bulk(ids) do
{:ok, %{users: users}} ->
users
{:error, _err} ->
{:error}
{:api_error, _err} ->
{:error}
end
end
I prefer to have a generic data loader which can be used to load users by passing different fields, so I avoided using batch resolution(API accepts user IDs in batch)
When I’m running the following query, I see multiple Loading users logs(multiple API calls)
query {
myRecentConversations{
id
content
createdAt
unreadCount
sender{
id
username
avatar
}
}
}
Why dataloader is not loading all users per this GraphQL query in a batch? I’ve used Facebook Dataloader in JS projects and it loads all data in a batch when running in a single graphql query context unlike this.
Is there something I can do to make this execute a batch call to API?
