Add a tenant change hook

lib/acts_as_tenant.rb

@@ -16,6 +16,16 @@ module ActsAsTenant
 
   class Current < ActiveSupport::CurrentAttributes
     attribute :current_tenant, :acts_as_tenant_unscoped
+
+    def current_tenant=(tenant)
+      super.tap do
+        configuration.tenant_change_hook.call(tenant) if configuration.tenant_change_hook.present?
+      end
+    end
+
+    def configuration
+      Module.nesting.last.class_variable_get(:@@configuration)
+    end
   end
 
   class << self

lib/acts_as_tenant/configuration.rb

@@ -1,6 +1,7 @@
 module ActsAsTenant
   class Configuration
     attr_writer :require_tenant, :pkey
+    attr_reader :tenant_change_hook
 
     def require_tenant
       @require_tenant ||= false
@@ -27,5 +28,10 @@ def job_scope=(scope)
         scope
       end
     end
+
+    def tenant_change_hook=(hook)
+      raise(ArgumentError, "tenant_change_hook must be a Proc") unless hook.is_a?(Proc)
+      @tenant_change_hook = hook
+    end
   end
 end

spec/acts_as_tenant/configuration_spec.rb

@@ -59,5 +59,33 @@
 
       expect(ActsAsTenant.should_require_tenant?).to eq(false)
     end
+
+    it "runs a hook on current_tenant" do
+      truthy = false
+      ActsAsTenant.configure do |config|
+        config.tenant_change_hook = lambda do |tenant|
+          truthy = true
+        end
+      end
+
+      ActsAsTenant.current_tenant = "foobar"
+
+      expect(truthy).to eq(true)
+    end
+
+    it "runs a hook on with_tenant" do
+      truthy = false
+      ActsAsTenant.configure do |config|
+        config.tenant_change_hook = lambda do |tenant|
+          truthy = true
+        end
+      end
+
+      ActsAsTenant.with_tenant("foobar") do
+        # do nothing
+      end
+
+      expect(truthy).to eq(true)
+    end
   end
 end