Restrict Query.users field to admin users and add Query.user field

app/graphql/types/query_type.rb

@@ -40,6 +40,10 @@ class QueryType < Types::BaseObject
       argument :id, Types::GlobalIdType[::Namespace], required: true, description: 'GlobalID of the target namespace'
     end
 
+    field :user, Types::UserType, null: true, description: 'Find a user' do
+      argument :id, Types::GlobalIdType[::User], required: true, description: 'GlobalID of the target user'
+    end
+
     field :users, Types::UserType.connection_type, null: false, description: 'Find users'
 
     field :global_runtimes, Types::RuntimeType.connection_type, null: false, description: 'Find runtimes'
@@ -83,7 +87,13 @@ def namespace(id:)
       SagittariusSchema.object_from_id(id)
     end
 
+    def user(id:)
+      SagittariusSchema.object_from_id(id)
+    end
+
     def users
+      return User.none unless Ability.allowed?(context[:current_authentication], :list_users, :global)
+
       User.all
     end
 

app/policies/global_policy.rb

@@ -20,5 +20,6 @@ class GlobalPolicy < BasePolicy
     enable :update_runtime
     enable :delete_runtime
     enable :rotate_runtime_token
+    enable :list_users
   end
 end

docs/graphql/object/query.md

@@ -68,3 +68,13 @@ Returns [`Organization`](../object/organization.md).
 |------|------|-------------|
 | `id` | [`OrganizationID`](../scalar/organizationid.md) | GlobalID of the target organization |
 | `name` | [`String`](../scalar/string.md) | Name of the target organization |
+
+### user
+
+Find a user
+
+Returns [`User`](../object/user.md).
+
+| Name | Type | Description |
+|------|------|-------------|
+| `id` | [`UserID!`](../scalar/userid.md) | GlobalID of the target user |

spec/graphql/types/query_type_spec.rb

@@ -12,6 +12,7 @@
       organization
       organizations
       users
+      user
       global_runtimes
       namespace
       userAbilities

spec/requests/graphql/query/user_query_spec.rb

@@ -0,0 +1,65 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+RSpec.describe 'user Query' do
+  include GraphqlHelpers
+
+  subject(:query!) { post_graphql query, current_user: current_user }
+
+  let(:target_user) { create(:user) }
+  let(:query) do
+    <<~QUERY
+      query {
+        user(id: "#{target_user.to_global_id}") {
+          id
+          username
+        }
+      }
+    QUERY
+  end
+
+  context 'when anonymous' do
+    let(:current_user) { nil }
+
+    it 'returns nil due to read_user authorization on UserType' do
+      query!
+
+      expect(graphql_data_at(:user)).to be_nil
+    end
+  end
+
+  context 'when logged in as regular user' do
+    let(:current_user) { create(:user) }
+
+    it 'returns the user' do
+      query!
+
+      expect(graphql_data_at(:user, :id)).to eq(target_user.to_global_id.to_s)
+      expect(graphql_data_at(:user, :username)).to eq(target_user.username)
+    end
+  end
+
+  context 'when logged in as admin user' do
+    let(:current_user) { create(:user, :admin) }
+
+    it 'returns the user' do
+      query!
+
+      expect(graphql_data_at(:user, :id)).to eq(target_user.to_global_id.to_s)
+      expect(graphql_data_at(:user, :username)).to eq(target_user.username)
+    end
+  end
+
+  context 'when querying self' do
+    let(:current_user) { create(:user) }
+    let(:target_user) { current_user }
+
+    it 'returns the user' do
+      query!
+
+      expect(graphql_data_at(:user, :id)).to eq(current_user.to_global_id.to_s)
+      expect(graphql_data_at(:user, :username)).to eq(current_user.username)
+    end
+  end
+end

spec/requests/graphql/query/users_query_spec.rb

@@ -0,0 +1,52 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+RSpec.describe 'users Query' do
+  include GraphqlHelpers
+
+  let(:query) do
+    <<~QUERY
+      query {
+        users {
+          nodes {
+            id
+            username
+          }
+        }
+      }
+    QUERY
+  end
+
+  before do
+    create(:user)
+    create(:user)
+    create(:user)
+
+    post_graphql query, current_user: current_user
+  end
+
+  context 'when anonymous' do
+    let(:current_user) { nil }
+
+    it 'returns an error' do
+      expect(graphql_data_at(:users, :nodes)).to be_empty
+    end
+  end
+
+  context 'when logged in as regular user' do
+    let(:current_user) { create(:user) }
+
+    it 'returns an error' do
+      expect(graphql_data_at(:users, :nodes)).to be_empty
+    end
+  end
+
+  context 'when logged in as admin user' do
+    let(:current_user) { create(:user, :admin) }
+
+    it 'returns all users' do
+      expect(graphql_data_at(:users, :nodes)).to have_attributes(length: 4)
+    end
+  end
+end