# Sub Applications - Mounts

If you need to have two independent FastAPI applications, with their own independent OpenAPI and their own docs UIs, you can have a main app and "mount" one (or more) sub-application(s).

## Mounting a **FastAPI** application

"Mounting" means adding a completely "independent" application in a specific path, that then takes care of handling everything under that path, with the _path operations_ declared in that sub-application.

        }

        in 5..7 -> {
          data.writeByte('\n'.code) // 'data' on a line of its own.
        }

        in 8..9 -> {
          id = source.readUtf8LineStrict().takeIf { it.isNotEmpty() }
        }

        in 10..12 -> {
          id = null // 'id' on a line of its own.
        }

        in 13..14 -> {
          type = source.readUtf8LineStrict().takeIf { it.isNotEmpty() }
        }

All the **logic** about how to register the URLs for webhooks and the code to actually send those requests is up to you. You write it however you want to in **your own code**.

## Documenting webhooks with **FastAPI** and OpenAPI

# You can define multiple automations in a .cm file, but each automation name should be unique
# within the file.  We keep each automation (or very closely related group of automations) in
# its own file.

on:
  - pr_created
  - commit
  - comment_added

automations:

  # Also post a comment that lists the best experts for the files that were modified.
  comment_experts:
    if:

# You can define multiple automations in a .cm file, but each automation name should be unique
# within the file.  We keep each automation (or very closely related group of automations) in
# its own file.

on:
  - pr_created
  - commit
  - comment_added

automations:

  javadoc_on_new_files:
    # Triggered for new Java files that lack Javadoc content.
    if:

Not every module contributes to every runtime.

The core-runtime module defines each runtime:

- The target JVM for the runtime. Each runtime has its own JVM compatibility constraints.
- Some base services that are available to code hosted by the runtime. This varies by runtime.

So, even with the code above that doesn't use Pydantic explicitly, FastAPI is using Pydantic to convert those standard dataclasses to Pydantic's own flavor of dataclasses.

And of course, it supports the same:

* data validation
* data serialization
* data documentation, etc.

//
// TypeMeta is provided here for convenience. You may use it directly from this package or define
// your own with the same fields.
//
// +k8s:deepcopy-gen=false
// +protobuf=true
// +k8s:openapi-gen=true
message TypeMeta {
  // +optional
  optional string apiVersion = 1;

  // +optional

* Then it starts `Listening at: http://0.0.0.0:80`.
* Then it detects that it has to use the worker class at `uvicorn.workers.UvicornWorker`.
* And then it starts **4 workers**, each with its own PID: `19511`, `19513`, `19514`, and `19515`.

# You can define multiple automations in a .cm file, but each automation name should be unique
# within the file.  We keep each automation (or very closely related group of automations) in
# its own file.

on:
  - pr_created
  - commit
  - comment_added

automations:

  # If someone is a primary author of the files in a change, but NOT the pr author, automatically add them as a reviewer.