Add latest changes from gitlab-org/gitlab@master

1 files changed, 102 insertions, 0 deletions

diff --git a/doc/development/repository_storage_moves/index.md b/doc/development/repository_storage_moves/index.md
new file mode 100644
index 00000000000..578bc1eabee
--- /dev/null
+++ b/doc/development/repository_storage_moves/index.md
@@ -0,0 +1,102 @@
+---
+stage: Create
+group: Source Code
+info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/product/ux/technical-writing/#assignments
+---
+
+# Project Repository Storage Moves
+
+This document was created to help contributors understand the code design of
+[project repository storage moves](../../api/project_repository_storage_moves.md).
+Read this document before making changes to the code for this feature.
+
+This document is intentionally limited to an overview of how the code is
+designed, as code can change often. To understand how a specific part of the
+feature works, view the code and the specs. The details here explain how the
+major components of the Code Owners feature work.
+
+NOTE:
+This document should be updated when parts of the codebase referenced in this
+document are updated, removed, or new parts are added.
+
+## Business logic
+
+- `Projects::RepositoryStorageMove`: Tracks the move, includes state machine.
+  - Defined in `app/models/projects/repository_storage_move.rb`.
+- `RepositoryStorageMovable`: Contains the state machine logic, validators, and some helper methods.
+  - Defined in `app/models/concerns/repository_storage_movable.rb`.
+- `Project`: The project model.
+  - Defined in `app/models/project.rb`.
+- `CanMoveRepositoryStorage`: Contains helper methods that are into `Project`.
+  - Defined in `app/models/concerns/can_move_repository_storage.rb`.
+- `API::ProjectRepositoryStorageMoves`: API class for project repository storage moves.
+  - Defined in `lib/api/project_repository_storage_moves.rb`.
+- `Entities::Projects::RepositoryStorageMove`: API entity for serializing the `Projects::RepositoryStorageMove` model.
+  - Defined in `lib/api/entities/projects/repository_storage_moves.rb`.
+- `Projects::ScheduleBulkRepositoryShardMovesService`: Service to schedule bulk moves.
+  - Defined in `app/services/projects/schedule_bulk_repository_shard_moves_service.rb`.
+- `ScheduleBulkRepositoryShardMovesMethods`: Generic methods for bulk moves.
+  - Defined in `app/services/concerns/schedule_bulk_repository_shard_moves_methods.rb`.
+- `Projects::ScheduleBulkRepositoryShardMovesWorker`: Worker to handle bulk moves.
+  - Defined in `app/workers/projects/schedule_bulk_repository_shard_moves_worker.rb`.
+- `Projects::UpdateRepositoryStorageWorker`: Finds repository storage move and then calls the update storage service.
+  - Defined in `app/workers/projects/update_repository_storage_worker.rb`.
+- `UpdateRepositoryStorageWorker`: Module containing generic logic for `Projects::UpdateRepositoryStorageWorker`.
+  - Defined in `app/workers/concerns/update_repository_storage_worker.rb`.
+- `Projects::UpdateRepositoryStorageService`: Performs the move.
+  - Defined in `app/services/projects/update_repository_storage_service.rb`.
+- `UpdateRepositoryStorageMethods`: Module with generic methods included in `Projects::UpdateRepositoryStorageService`.
+  - Defined in `app/services/concerns/update_repository_storage_methods.rb`.
+- `Projects::UpdateService`: Schedules move if the passed parameters request a move.
+  - Defined in `app/services/projects/update_service.rb`.
+- `PoolRepository`: Ruby object representing Gitaly `ObjectPool`.
+  - Defined in `app/models/pool_repository.rb`.
+- `ObjectPool::CreateWorker`: Worker to create an `ObjectPool` via `Gitaly`.
+  - Defined in `app/workers/object_pool/create_worker.rb`.
+- `ObjectPool::JoinWorker`: Worker to join an `ObjectPool` via `Gitaly`.
+  - Defined in `app/workers/object_pool/join_worker.rb`.
+- `ObjectPool::ScheduleJoinWorker`: Worker to schedule an `ObjectPool::JoinWorker`.
+  - Defined in `app/workers/object_pool/schedule_join_worker.rb`.
+- `ObjectPool::DestroyWorker`: Worker to destroy an `ObjectPool` via `Gitaly`.
+  - Defined in `app/workers/object_pool/destroy_worker.rb`.
+- `ObjectPoolQueue`: Module to configure `ObjectPool` workers.
+  - Defined in `app/workers/concerns/object_pool_queue.rb`.
+- `Repositories::ReplicateService`: Handles replication of data from one repository to another.
+  - Defined in `app/services/repositories/replicate_service.rb`.
+
+## Flow
+
+These flowcharts should help explain the flow from the endpoints down to the
+models for different features.
+
+### Schedule a repository storage move via the API
+
+```mermaid
+graph TD
+  A[<code>POST /api/:version/project_repository_storage_moves</code>] --> C
+  B[<code>POST /api/:version/projects/:id/repository_storage_moves</code>] --> D
+  C[Schedule move for each project in shard] --> D[Set state to scheduled]
+  D --> E[<code>after_transition callback</code>]
+  E --> F{<code>set_repository_read_only!</code>}
+  F -->|success| H[Schedule repository update worker]
+  F -->|error| G[Set state to failed]
+```
+
+### Moving the storage after being scheduled
+
+```mermaid
+graph TD
+  A[Repository update worker scheduled] --> B{State is scheduled?}
+  B -->|Yes| C[Set state to started]
+  B -->|No| D[Return success]
+  C --> E{Same filesystem?}
+  E -.-> G[Set project repo to writable]
+  E -->|Yes| F["Mirror repositories (project, wiki, design, & pool)"]
+  G --> H[Update repo storage value]
+  H --> I[Set state to finished]
+  I --> J[Associate project with new pool repository]
+  J --> K[Unlink old pool repository]
+  K --> L[Update project repository storage values]
+  L --> N[Remove old paths if same filesystem]
+  N --> M[Set state to finished]
+```