Configure the build base for an ExpressJS app¶

When using the expressjs-framework extension, there are four different cases for customising the Ubuntu base and the Node.js version to be included. The main differences between the cases are:

Whether to use the bare base or Ubuntu 24.04 base.
Whether Node.js is installed from Ubuntu package archive or the NPM plugin.

The remainder of this page discusses the combinations of Ubuntu bases and sources for Node.js.

Ubuntu 24.04 base, Node.js from Ubuntu package archive¶

rockcraft.yaml¶

base: ubuntu@24.04
extensions:
    - expressjs-framework

In this case, the NPM plugin copies the app’s files and installs its dependencies. Node.js then provides a runtime and launches the app. The NPM and Node.js versions are determined by the versions of NPM and Node.js shipped with the Ubuntu base. This link to the Ubuntu archive shows the NPM version shipped with the Ubuntu 24.04 base.

Ubuntu 24.04 base, Node.js from NPM plugin¶

rockcraft.yaml¶

base: ubuntu@24.04
extensions:
    - expressjs-framework
parts:
    expressjs-framework/install-app:
        npm-include-node: true
        npm-node-version: 20.12

In this case, the NPM plugin copies the app’s files and installs its dependencies. Node.js and NPM is installed by the NPM plugin.

Bare base, Node.js from Ubuntu package archive¶

rockcraft.yaml¶

base: bare
build-base: ubuntu@24.04
extensions:
    - expressjs-framework

Bare base, Node.js from NPM plugin¶

rockcraft.yaml¶

base: bare
build-base: ubuntu@24.04
parts:
    expressjs-framework/install-app:
        npm-include-node: true
        npm-node-version: 20.12

In this case, the NPM plugin copies the app’s files and installs its dependencies. Node.js then provides a runtime and launches the app. Node.js and NPM is installed by the NPM plugin. For different possible values for the npm-node-version key, refer to NPM plugin documentation.