jberling
I have this action, which is not working the way I expected.
create :build do
accept [:identity_id]
change set_attribute(:token, Helpers.rand_token())
change set_attribute(:inserted_at, DateTime.utc_now())
end
token and inserted_at get a fixed value from when the code was evaluated, if I’m not mistaken. But I want to, of course, generate a new value every time the action runs.
I figured out I could accomplish it this way:
create :build do
accept \[:identity\_id]
change fn changeset, \_ ->
changeset
|> Ash.Changeset.change\_attribute(:token, Helpers.rand\_token())
|> Ash.Changeset.change\_attribute(:inserted\_at, DateTime.utc\_now())
end
end
It feels a bit clunky. Is there a more straightforward way? I tried to pass a thunk instead of the value directly to set_attribute, but it doesn’t seem to work.
Or are there other ways to do this in a more idiomatic way? To generate values when a resource is created, I mean.
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chazwatkins
Since both of the functions are zero-arity, you can do this
If you provide a zero-arity function, it will be called, and the value will be set. Otherwise, you must do the anonymous function route or create a change module.
Also, for
:inserted_at, you can docreate_timestamp :inserted_atin the attributes section instead of a manual change. Attributes — ash v3.29.3jberling
Nice! Thanks!
I was bitten by my lack of Elixir skills.
I tried
change set_attribute(:token, Helpers.rand_token)andchange set_attribute(:token, fn -> Helpers.rand_token() end). Neither worked.Now I need to learn why I must capture the function, and why
Helpers.rand_tokenor evenHelpers.rand_token/0differs from&Helpers.rand_token/0. I suppose it’s because of the different scopes for variables and functions.chazwatkins
I’m surprised the
set_attribute(:token, fn -> Helpers.rand_token() end)didn’t work. I’ll ask on the discord and let you know.If you aren’t on Discord, it’s a great place to learn Ash
jberling
Ok, thanks again.
I’ll join Discord.