# Architecture

The design mostly follows what's illustrated below. Below is a simplified runtime view of invoking `cedana dump runc ...`:

<figure><img src="https://github.com/user-attachments/assets/9e6842bd-03d1-4889-b23e-11dcbe7ea25f" alt="Cedana&#x27;s plugin architecture"><figcaption><p>Cedana's plugin architecture</p></figcaption></figure>

1. The subcommand `cedana dump runc ...` is only available if the runc plugin is exporting the `DumpCmd` symbol (check `plugins/runc/main.go`). The runc plugin only sets the *specific* flags it needs (such as `--id`, `--root`), while the parent cmd handles all the common flags, and sending the request to the daemon.
2. The daemon receives the request, and runs it through a list of adapters, before finally sending it to CRIU. If the request's `type` is `runc`, it will use the `DumpMiddleware` exported by the runc plugin and plug it in the adapter chain. See `internal/cedana/dump.go`:

{% @github-files/github-code-block url="<https://github.com/cedana/cedana/blob/3a6a8000e207f7480dbda977eb9181f09b514cc4/internal/cedana/dump.go#L30-L51>" %}

3. This way, the runc plugin only implements the specifics of the runc runtime, while the daemon handles the common logic, and invoking CRIU.
4. The same pattern is followed for `dump`, `restore`, `run`, and `manage`.

## Features

Symbols that can be exported by a plugin are well-typed and are defined in `pkg/features/supported.go`. A `feature` implements a convenient method called `IfAvailable(do func(), filter ...string)`, which is the *only* method you will ever need to access a feature exported by a plugin. An example usage:

{% @github-files/github-code-block url="<https://github.com/cedana/cedana/blob/3a6a8000e207f7480dbda977eb9181f09b514cc4/internal/cedana/dump.go#L98-L104>" %}

A useful helper command is `cedana features` (alias of `cedana plugin features`), which lists all the features supported by all the plugins. This is useful for debugging, when implementing a new feature, or when you want to know what a plugin supports. Use the `--errors` flag to also output all errors encountered while loading the plugins.

{% hint style="info" %}
See [features](/daemon/get-started/features.md) for more info.
{% endhint %}

![Output from cedana plugin features](https://github.com/user-attachments/assets/90578e51-c7f1-44b9-b056-dc1cbdd89785)


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://docs.cedana.ai/daemon/developer-guides/architecture.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.