# `MishkaCmsMigration.Application`
[🔗](https://github.com/mishka-group/mishka_cms_migration/blob/v0.0.1/lib/mishka_cms_migration/application.ex#L5)

The migration extension's OTP application. It supervises every mishka_installer plugin the
extension ships (`plugins/0`). A plugin registers on the event it listens on once it is supervised
here.

The plugins are the sources (`sources/0`, each a plugin on `"migration:sources"`, see
`MishkaCmsMigration.Source`) and the targets (`targets/0`, each on `"migration:targets"`, see
`MishkaCmsMigration.Target`) it ships; the one that makes it installable on a site,
`MishkaCmsMigration.Provision`; the admin page's sidebar entry,
`MishkaCmsMigrationWeb.SidebarMenu`; and the runs' log in the core's activity log
(`MishkaCmsMigration.Activity`, on `"activity:sources"`).

At boot it also attaches the Oban telemetry handler that fails the run of a migration job Oban
discards (`MishkaCmsMigration.Workers.attach/0`).

The migration jobs run on the host's Oban, on a `migration` queue the host declares; the host
starts Oban through `AshOban.config/2` with its `ash_domains`, which refuses to start without the
queue. Each site has one run dry running or importing at a time
(`MishkaCmsMigration.MigrationRun`'s `:one_active_per_site`); the queue's limit is how many sites
migrate at once across the whole installation. With
`queues: [migration: 1]` one site migrates while the others' jobs wait their turn; a host with
many sites may raise it, at the cost of that many imports writing at the same time.

# `blog_kinds`

```elixir
@spec blog_kinds() :: [String.t()]
```

The kinds the Blog targets write, known where the Blog is not loaded: an item of one of them whose
target is not installed waits for an admin's decision, Wait for the Blog or Leave out
(`"blog_missing"`, `MishkaCmsMigration.Workers.Helpers.Decision`), rather than being skipped as a
kind nothing imports.

# `plugins`

```elixir
@spec plugins() :: [module()]
```

Every mishka_installer plugin this extension ships, all of which `start/2` supervises. A plugin
left out of it never registers, so the event it listens on never reaches it.

# `sources`

```elixir
@spec sources() :: [module()]
```

The sources this extension ships, each a plugin on `"migration:sources"`: WordPress over its REST
API (`MishkaCmsMigration.Sources.WordPress`) and from its export file
(`MishkaCmsMigration.Sources.WordPressFile`).

# `targets`

```elixir
@spec targets() :: [module()]
```

The targets this extension ships, each a plugin on `"migration:targets"` writing one kind of item
through an existing CMS action: files into the CMS's media library
(`MishkaCmsMigration.Targets.CmsMedia`), the site's name and pictures into its settings
(`MishkaCmsMigration.Targets.CmsSetting`), Elementor's global colours and fonts into a stylesheet
of theme tokens (`MishkaCmsMigration.Targets.CmsStylesheet`), pages into the CMS's pages
(`MishkaCmsMigration.Targets.CmsPage`), the main menu into the links of the site layout's header
(`MishkaCmsMigration.Targets.CmsLayout`),
authors, categories, tags, posts and comments into Mishka Blog
(`MishkaCmsMigration.Targets.BlogBlogger`, `MishkaCmsMigration.Targets.BlogCollection`,
`MishkaCmsMigration.Targets.BlogTag`, `MishkaCmsMigration.Targets.BlogPost`,
`MishkaCmsMigration.Targets.BlogComment`), and each post's old address into a CMS redirect to it
(`MishkaCmsMigration.Targets.PostRedirect`).

Mishka Blog is an optional dependency, and each Blog target is defined only where it is loaded,
so on a node without it they are left out, and the items of their kinds (`blog_kinds/0`) wait for
the Blog (`"blog_missing"`).

---

*Consult [api-reference.md](api-reference.md) for complete listing*