Application limits development

This document provides a development guide for contributors to add application limits to GitLab.

Documentation

First of all, you have to gather information and decide which are the different limits that will be set for the different GitLab tiers. You also need to coordinate with others to document and communicate those limits.

There is a guide about introducing application limits.

Development

The merge request to configure maximum number of webhooks per project is a good example about configuring application limits.

Insert database plan limits

In the plan_limits table, you have to create a new column and insert the limit values. It's recommended to create separate migration script files.

Add new column to the plan_limits table with non-null default value 0, eg:
```
add_column(:plan_limits, :project_hooks, :integer, default: 0, null: false)
```
NOTE: Note: Plan limits entries set to 0 mean that limits are not enabled.

Insert plan limits values into the database using create_or_update_plan_limit migration helper, eg:

create_or_update_plan_limit('project_hooks', 'free', 10)
create_or_update_plan_limit('project_hooks', 'bronze', 20)
create_or_update_plan_limit('project_hooks', 'silver', 30)
create_or_update_plan_limit('project_hooks', 'gold', 100)

Plan limits validation

Get current limit

Access to the current limit can be done through the project or the namespace, eg:

project.actual_limits.project_hooks

Check current limit

There is one method PlanLimits#exceeded? to check if the current limit is being exceeded. You can use either an ActiveRecord object or an Integer.

Ensures that the count of the records does not exceed the defined limit, eg:

project.actual_limits.exceeded?(:project_hooks, ProjectHook.where(project: project))

Ensures that the number does not exceed the defined limit, eg:

project.actual_limits.exceeded?(:project_hooks, 10)

`Limitable` concern

The Limitable concern can be used to validate that a model does not exceed the limits. It ensures that the count of the records for the current model does not exceed the defined limit.

NOTE: Note: The name (pluralized) of the plan limit introduced in the database (project_hooks) must correspond to the name of the model we are validating (ProjectHook).

class ProjectHook
  include Limitable
end