App Hosting adapters

Overview

App Hosting provides configuration-free build and deploy support for Web apps developed in these frameworks:

• Next.js 13+
• Angular 17.2+

This repo holds the code for the adapters that enable support for these frameworks. At a high level these adapters transform framework specific configurations into an output bundle spec that App Hosting can use to configure frameworks support. For more information see Framework integration.

App Hosting output bundle

The App Hosting output bundle is a file based specification that allows different frameworks to configure and customize their App Hosting deployment for enhanced support.

Any framework that can generate a build output in accordance with the App Hosting output bundle can be deployed on App Hosting.

The output bundle primarily consists of a bundle.yaml file that sits inside of the .apphosting directory. This bundle.yaml contains all the ways that frameworks can configure App Hosting when users deploy their applications.

Note

App Hosting technically supports all all node applications, but no custom framework features will be enabled without the output bundle.

Output bundle Schema

The output bundle is contained in a single file:

.apphosting/bundle.yaml

As long as this file exists and follows the schema, App Hosting will be able to process the build properly.

The schema can also be found in source

interface OutputBundle {
  version: "v1"
  runConfig: RunConfig;
  metadata: Metadata;
}

Version

The version represents which output bundle version is currently being used. The current version is v1.

RunConfig

The runConfig fields configures the Cloud Run service associated with the App Hosting Backend.

interface RunConfig {
  runCommand: string;
  environmentVariables?: EnvVarConfig[];
  concurrency?: number;
  cpu?: number;
  memoryMiB?: number;
  minInstances?: number;
  maxInstances?: number;
}

Field	Type	Description	Required?
runCommand	string	Command to start the server (e.g. node dist/index.js). Assume this command is run from the root dir of the workspace. This should be the productionized version of the server start command.	y
environmentVariables	EnvVarConfig[]	Environment variables present in the server execution environment.	n
concurrency	number	The maximum number of concurrent requests that each server instance can receive.	n
cpu	number	The number of CPUs used in a single server instance.	n
memoryMiB	number	The amount of memory available for a server instance.	n
minInstance	number	The limit on the minimum number of function instances that may coexist at a given time.	n
MaxInstance	number	The limit on the maximum number of function instances that may coexist at a given time.	n

Many of these fields are shared with apphosting.yaml. See the runConfig reference documentation for additional context and default values.

EnvVarConfig

interface EnvVarConfig {
  variable: string;
  value: string;
  availability: 'RUNTIME'
}

Field	Type	Description	Required?
variable	string	Name of the environment variable	y
value	string	Value associated with the environment variable	y
availability	RUNTIME	Where the variable will be available. For now this will always be RUNTIME	y

Metadata

interface Metadata {
  adapterPackageName: string;
  adapterVersion: string;
  framework: string;
  frameworkVersion?: string;
}

Field	Type	Description	Required?
adapterPackageName	string	Name of the adapter (this should be the npm package name)	y
adapterVersion	string	Version of the adapter	y
framework	string	Name of the framework that is being supported	y
frameworkVersion	string	Version of the framework that is being supported	n

Here is a sample bundle.yaml file putting all this together:

> cat .apphosting/bundle.yaml

version: v1
runConfig:
  runCommand:
    - node
    - dist/index.js
  environmentVariables:
    - variable: VAR
      value: 8080
      availability: RUNTIME
  concurrency: 80
  cpu: 2
  memoryMiB: 512
  minInstances: 0
  maxInstances: 14
    
metadata:
  adapterNpmPackageName: npm-name
  adapterVersion: 12.0.0
  frameworkNpmPackageName: framework-name
  adapterVersion: 1.0.0

As long as you have the bundle.yaml in this format, App Hosting will be able to deploy any framework that supports server side rendering.