func/docs/guides/func_yaml.md

Project Configuration with func.yaml

The func.yaml file contains configuration information for your function project. Generally, these values are used when you execute a func CLI command. For example, when func build is run, the CLI uses the value for the builder field. In many cases, these values may be overridden by command line flags or environment variables. For more information about overriding these values, consult the Commands document.

Many of the fields are generated for you when you create, build and deploy your function. However there are a few that you may use to tweak things such as the function name, and the image name.

Fields

The following fields are used in func.yaml.

builder

Specifies the buildpack builder image to use when building the function. In most cases, this value should not be changed.

builderMap

Some function runtimes may be built in multiple ways. For example, a Quarkus function may be built for the JVM, or as a native binary. The builderMap field will contain all of the available builders for a given runtime. Although it's typically unnecessary to modify the builder field, using values from builderMap is OK.

env

The env field allows you to set environment variables that will be available to your function at runtime. For example, to set a MODE environment variable to debug when the function is deployed, your func.yaml file may look like this. To unset variables use a dash suffix. For example, to unset MODE, use MODE-.

env:
  MODE: debug
  API_KEY: {{ env.API_KEY }}
  VAR_TO_UNSET-: ""

image

This is the image name for your function after it has been built. This field may be modified and func will create your image with the new name the next time you run kn func build or kn func deploy.

imageDigest

This is the sha256 hash of the image manifest when it is deployed. This value should not be modified.

name

The name of your function. This value will be used as the name for your service when it is deployed. This value may be changed to rename the function on subsequent deployments.

namespace

The Kubernetes namespace where your function will be deployed.

runtime

The language runtime for your function. For example python.

trigger

The invocation event that triggers your function. Possible values are http for plain HTTP requests, and events for CloudEvent triggered functions.

Environment Variables

Any of the fields in func.yaml may contain a reference to an environment variable available in the local environment. For example, if I would like to avoid storing sensitive information such as an API key in my function configuration, I may have this value set from the local environment. To do this, prefix the local environment variable with {{ and }} and prefix the name with env.. For example:

env:
  API_KEY: {{ env.API_KEY }}