Ash Framework•6mo ago

`change manage_relationship(...type: :remove)` not working

I have a many_to_many relationship between Organization and SubscriptionPlan. The Organization has the following two actions:

    update :subscribe do
      argument :plan, :struct, constraints: [instance_of: SubscriptionPlan]
      accept []
      require_atomic? false
      change manage_relationship(:plan, :subscription_plans, type: :append)
    end

    update :unsubscribe do
      argument :plan, :struct, constraints: [instance_of: SubscriptionPlan]
      accept []
      require_atomic? false
      change manage_relationship(:plan, :subscription_plans, type: :remove)
    end

    update :subscribe do
      argument :plan, :struct, constraints: [instance_of: SubscriptionPlan]
      accept []
      require_atomic? false
      change manage_relationship(:plan, :subscription_plans, type: :append)
    end

    update :unsubscribe do
      argument :plan, :struct, constraints: [instance_of: SubscriptionPlan]
      accept []
      require_atomic? false
      change manage_relationship(:plan, :subscription_plans, type: :remove)
    end

The :subscribe action seems to work fine. But the :unsubscribe action fails with the following :invalid error:

[%Ash.Error.Changes.InvalidRelationship{relationship: :subscription_plans, message: "changes would create a new related record", splode: Ash.Error, bread_crumbs: ["Error returned from: MyApp.Accounts.Organization.unsubscribe"]

[%Ash.Error.Changes.InvalidRelationship{relationship: :subscription_plans, message: "changes would create a new related record", splode: Ash.Error, bread_crumbs: ["Error returned from: MyApp.Accounts.Organization.unsubscribe"]

I'm a little baffled by this one. Also, if I change the manage_relationship options from type: :remove to the following:

[
  on_no_match: :ignore,
  on_match: :unrelate,
  on_missing: :ignore
]

[
  on_no_match: :ignore,
  on_match: :unrelate,
  on_missing: :ignore
]

(this basically just changes on_no_match from :error to :ignore) ... my test also fails. It seems to remove the subscription from the Organization but not the SubscriptionPlan:

plan = plan |> Ash.load!([:subscribers], actor: user) |> dbg
assert plan.subscribers |> length == 0

plan = plan |> Ash.load!([:subscribers], actor: user) |> dbg
assert plan.subscribers |> length == 0

Not sure what I'm doing wrong here 🤔

Solution:

So the mistake I was making was in my accessing_through policy: ```elixir policy accessing_from(MyApp.Accounts.Organization, :subscribers) do authorize_if always()...

Jump to solution

14 Replies

⿻ eileenOP•6mo ago

Could it have to do with the relationship / policies?

###################
# On Organization #
###################
  relationships do
    many_to_many :subscription_plans, MyApp.Subscriptions.SubscriptionPlan do
      through MyApp.Subscriptions.OrgSubscription
      source_attribute_on_join_resource :organization_id
      destination_attribute_on_join_resource :subcription_plan_id
    end
  end

  policies do
    bypass actor_attribute_equals(:role, :super) do
      authorize_if always()
    end

    bypass actor_attribute_equals(:role, :admin) do
      authorize_if always()
    end

    policy action_type([:read, :update, :destroy]) do
      authorize_if(relates_to_actor_via(:owner))
    end

    policy action_type(:create) do
      authorize_if always()
    end
  end

#######################
# on SubscriptionPlan #
#######################

  relationships do
    many_to_many :subscribers, MyApp.Accounts.Organization do
      through MyApp.Subscriptions.OrgSubscription
      source_attribute_on_join_resource :subcription_plan_id
      destination_attribute_on_join_resource :organization_id
    end
  end

  policies do
    bypass actor_attribute_equals(:role, :super) do
      authorize_if always()
    end

    bypass actor_attribute_equals(:role, :admin) do
      authorize_if always()
    end

    policy do
      forbid_if always()
    end
  end

###################
# On Organization #
###################
  relationships do
    many_to_many :subscription_plans, MyApp.Subscriptions.SubscriptionPlan do
      through MyApp.Subscriptions.OrgSubscription
      source_attribute_on_join_resource :organization_id
      destination_attribute_on_join_resource :subcription_plan_id
    end
  end

  policies do
    bypass actor_attribute_equals(:role, :super) do
      authorize_if always()
    end

    bypass actor_attribute_equals(:role, :admin) do
      authorize_if always()
    end

    policy action_type([:read, :update, :destroy]) do
      authorize_if(relates_to_actor_via(:owner))
    end

    policy action_type(:create) do
      authorize_if always()
    end
  end

#######################
# on SubscriptionPlan #
#######################

  relationships do
    many_to_many :subscribers, MyApp.Accounts.Organization do
      through MyApp.Subscriptions.OrgSubscription
      source_attribute_on_join_resource :subcription_plan_id
      destination_attribute_on_join_resource :organization_id
    end
  end

  policies do
    bypass actor_attribute_equals(:role, :super) do
      authorize_if always()
    end

    bypass actor_attribute_equals(:role, :admin) do
      authorize_if always()
    end

    policy do
      forbid_if always()
    end
  end

So I assume it's that last policy do forbid_if always() end that's causing my trouble here. If I set the user's role to :admin or use authorize?: false when I call unsubscribe, the test passes. What I don't understand is how I can set a policy on the SubscriptionPlan that will allow deleting one of its OrgSubscription records Is the following advisable?

    update :unsubscribe do
      argument :plan, :struct, constraints: [instance_of: SubscriptionPlan]
      accept []
      require_atomic? false
      change manage_relationship(:plan, :subscription_plans, type: :remove, authorize?: false)
    end

    update :unsubscribe do
      argument :plan, :struct, constraints: [instance_of: SubscriptionPlan]
      accept []
      require_atomic? false
      change manage_relationship(:plan, :subscription_plans, type: :remove, authorize?: false)
    end

I've added authorize?: false to the change manage_relationship call on the Organization resource. The Organization itself is protected by policies. So does that mean its ok for some of its internal manage_relationship call to use authorize?: false?

barnabasj•6mo ago

https://hexdocs.pm/ash/Ash.Policy.Check.Builtins.html#accessing_from/2 This might work

⿻ eileenOP•6mo ago

Will give it a try 😄 Hmm. So accessing_from gives me the same error I started with:

    policy accessing_from(MyApp.Accounts.Organization, :subscribers) do
      authorize_if always()
    end

# results in error:

[%Ash.Error.Changes.InvalidRelationship{relationship: :subscription_plans, message: "changes would create a new related record", splode: Ash.Error, bread_crumbs: ["Error returned from: MyApp.Accounts.Organization.unsubscribe"]

    policy accessing_from(MyApp.Accounts.Organization, :subscribers) do
      authorize_if always()
    end

# results in error:

[%Ash.Error.Changes.InvalidRelationship{relationship: :subscription_plans, message: "changes would create a new related record", splode: Ash.Error, bread_crumbs: ["Error returned from: MyApp.Accounts.Organization.unsubscribe"]

This is a many_to_many relationship - not sure I mentioned that before

ZachDaniel•6mo ago

do you have other policies that apply? All policies that apply have to pass

⿻ eileenOP•6mo ago

On the SubscriptionPlan resource, which seems to be the one causing the trouble, these are my policies:

  policies do
    bypass actor_attribute_equals(:role, :super) do
      authorize_if always()
    end

    bypass actor_attribute_equals(:role, :admin) do
      authorize_if always()
    end

    policy accessing_from(MyApp.Accounts.Organization, :subscribers) do
      authorize_if always()
    end

    policy do
      forbid_if always()
    end
  end

  policies do
    bypass actor_attribute_equals(:role, :super) do
      authorize_if always()
    end

    bypass actor_attribute_equals(:role, :admin) do
      authorize_if always()
    end

    policy accessing_from(MyApp.Accounts.Organization, :subscribers) do
      authorize_if always()
    end

    policy do
      forbid_if always()
    end
  end

Then on the Organization resource, these are my policies:

  policies do
    bypass actor_attribute_equals(:role, :super) do
      authorize_if always()
    end

    bypass actor_attribute_equals(:role, :admin) do
      authorize_if always()
    end

    policy action_type([:read, :update, :destroy]) do
      authorize_if(relates_to_actor_via(:owner))
    end

    policy action_type(:create) do
      authorize_if always()
    end
  end

  policies do
    bypass actor_attribute_equals(:role, :super) do
      authorize_if always()
    end

    bypass actor_attribute_equals(:role, :admin) do
      authorize_if always()
    end

    policy action_type([:read, :update, :destroy]) do
      authorize_if(relates_to_actor_via(:owner))
    end

    policy action_type(:create) do
      authorize_if always()
    end
  end

The intermediate OrgSubscription resource doesn't have any policies

ZachDaniel•6mo ago

    policy do
      forbid_if always()
    end

    policy do
      forbid_if always()
    end

that forbids everyone from doing anything always And always applies

⿻ eileenOP•6mo ago

Unless bypassed .... got it

ZachDaniel•6mo ago

Careful of overusing bypasses

⿻ eileenOP•6mo ago

I'm only using them for admin / super users Oddly enough, removing the forbid_if always() policy has now resulted in a Forbidden error on both subscribe and unsubscribe actions I find policies generally to be slippery things Got it!

Solution

⿻ eileen•6mo ago

So the mistake I was making was in my accessing_through policy:

    policy accessing_from(MyApp.Accounts.Organization, :subscribers) do
      authorize_if always()
    end

    policy accessing_from(MyApp.Accounts.Organization, :subscribers) do
      authorize_if always()
    end

I thought that second parameter was supposed to refer to the relationship defined on the resource that was defining the policy, but it's actually the relationship defined on the resource being referenced in the policy.

⿻ eileenOP•6mo ago

So the corrected version is this:

    policy accessing_from(Insi.Accounts.Organization, :subscription_plans) do
      authorize_if always()
    end

    policy accessing_from(Insi.Accounts.Organization, :subscription_plans) do
      authorize_if always()
    end

Tests green ✅

⿻ eileenOP•6mo ago

Thank you!

ZachDaniel•6mo ago

🥳 haha I didn't even see that

⿻ eileenOP•6mo ago

Easy to miss Also the forbid_if always() was also important

Gaming

Programming

`change manage_relationship(...type: :remove)` not working

Did you find this page helpful?