Multi-tenant with hooks for all operations?

[frederikhors]

I'm coming from Bun which has Hooks too:

It is very easy with Bun to add a tenanted hook on each operation (even the select one):

type Player struct {
  Id   uint64
  Name string
}

var _ bun.BeforeSelectHook = (*Player)(nil)

func (*Player) BeforeSelect(ctx context.Context, query *bun.SelectQuery) error {
	query.Where("?TableAlias.tenant_id = ?", GetTenantID(ctx))

	return nil
}

var _ bun.BeforeInsertHook = (*Player)(nil)

func (*Player) BeforeInsert(ctx context.Context, query *bun.InsertQuery) error {
	query.Value("?TableAlias.tenant_id = ?", GetTenantID(ctx))

	return nil
}

var _ bun.BeforeUpdateHook = (*Player)(nil)

func (*Player) BeforeUpdate(ctx context.Context, query *bun.UpdateQuery) error {
	query.Where("?TableAlias.tenant_id = ?", GetTenantID(ctx))

	return nil
}

var _ bun.BeforeDeleteHook = (*Player)(nil)

func (*Player) BeforeDelete(ctx context.Context, query *bun.DeleteQuery) error {
	query.Where("?TableAlias.tenant_id = ?", GetTenantID(ctx))

	return nil
}

In this case I can rest assured that no one on the team will forget to add a query.Where("tenant_id=?") in the code because the hook saves me in all cases.

I'm learning Ent from today and saw this description on Readme for Tenant example which is not something I expect for it:

Is it a misprint?

Can you direct me to a guide for a multi-tenant with hooks for all operations?

I'm a bit scared because in this page https://entgo.io/docs/hooks there are no hook for operations like "Select".

[a8m]

Hey @frederikhors, for this use case, you can use the Privacy Filter Rules to apply filtering to all your queries/mutations (including Select).

Is it a misprint?

Fixed. Thanks for reporting this.

[a8m]

I implemented with Ent a few different approaches for multi-tenacy. Named-database per tenant, tenant edge, and tenant_id field. The field/edge-based approaches were implemented with FilterRule as follows:

func FilterTenantRule() privacy.QueryRule {
	type TenantFilter interface {
		WhereTenantID(int)
	}
	return privacy.FilterFunc(func(ctx context.Context, f privacy.Filter) error {
		t := viewer.TenantFromContext(ctx)
		tf, ok := f.(FilterTenantRule)
		if !ok {
			return privacy.Denyf("unexpected filter type %T. All schemas must include the Tenant mixin", f)
		}
		tf.WhereTenantID(t.ID)
		// Skip to the next privacy rule (equivalent to return nil).
		return privacy.Skip
	})
}

Let me know if it helps or if you need help with it.

[frederikhors]

@a8m I managed to get everything to work with the filter rule.

What I can't figure out now is if there is a way to avoid manually using the .SetTenant() in the .Create() methods.

Can I use a rule for this too?

[frederikhors]

I'm using Hooks. Do you think is the way to go?

[frederikhors]

For future people: I summarized issues here.