Create and Run Functions with Fn

October 12, 2021 ยท View on GitHub

This how-to covers how to create and test functions.

Create a Boilerplate Function with Init

Fn provides the init option to setup or create a function you can test. To created a "Hello World" function using boilerplate code type:

fn init --runtime node nodefn

The command generates four files:

  • func.js - A boilerplate Node.js JavaScript function.
  • func.yaml - A boilerplate YAML file containing boilerplate configuration options for the function.
  • package.json - A list of packages required for the function.
  • test.json - A file for running tests on your function.

The key Fn configuration file here is the func.yaml file. The file created from the sample command would be:

name: nodefn
version: 0.0.1
runtime: node
entrypoint: node func.js

For more information on possible value in the func.yaml file see Link to funcfile doc.

Set the Version Number when Creating a Function

By default, when the func.yaml file is created, the version is set to 0.0.1. If you with to start with a different number use the version command.

fn init --version 1.0.1  --runtime node t1

This creates a func.yaml file with a version set to 1.01.

name: t1
version: 1.0.1
runtime: node
entrypoint: node func.js

Create a func.yaml using an Existing Function File

You can create a func.yaml file from an existing function file. For example, if I have a function named func.js in a directory named t3. Run the init command:

fn init

Fn will find your function file, determine it is a type Node and generate a func.yaml for you. For example

name: t3
version: 0.0.1
runtime: node
entrypoint: node func.js

Configure image signature details in func.yaml

You can sign function images using Oracle OCI keys. This is supported only when Oracle Provider is used. For more details on signing images refer to OCIR Image Signature.

To sign the function image, add the following section to func.yaml before running the fn deploy command. The fn deploy command will push the function image to the OCI Container Registry (OCIR) and use the signing details provided to sign the function image in OCIR.

signing_details:
  image_compartment_id: ocid1.tenancy.oc1..aaaaaaaaba3____dsq
  kms_key_id: ocid1.key.oc1.phx.bbqehaq3aadfa.abyh______qlj
  kms_key_version_id: ocid1.keyversion.oc1.phx.0.bbqehaq3aadfa.acy6______mbb
  signing_algorithm: SHA_224_RSA_PKCS_PSS

where: