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.

builders

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 builders 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 builders is OK.

buildEnvs

This field allows you to set environment variables available to the builder/buildpack that builds the function. This environment variable is NOT set at runtime, use envs instead

1. Environment variable can be set directly from a value
2. Environment variable can be set from a local environment value. Eg. '{{ env:LOCAL_ENV_VALUE }}', for more details see Local Environment Variables section.

buildEnvs:
- name: EXAMPLE1                            # (1) env variable directly from a value
  value: value
- name: EXAMPLE2                            # (2) env variable from a local environment value
  value: '{{ env:LOCAL_ENV_VALUE }}'

For example, the below func.yaml snippet modifies the default Golang buildpack to build source code with 1.15 compiler version. Refer to respective buildpack documentation to know more about environment variables that modify behavior of the func build.

buildEnvs:
- name: BP_GO_VERSION
  value: '1.15'

envs

The envs field allows you to set environment variables that will be available to your function at runtime.

1. Environment variable can be set directly from a value
2. Environment variable can be set from a local environment value. Eg. '{{ env:LOCAL_ENV_VALUE }}', for more details see Local Environment Variables section.
3. Environment variable can be set from a key in a Kubernetes Secret or ConfigMap. This Secret/ConfigMap needs to be created before it is referenced in a function. Eg. '{{ secret:mysecret:key }}' where mysecret is the name of the Secret and key is the referenced key; or {{ configMap:myconfigmap:key }} where myconfigmap is the name of the ConfigMap and key is the referenced key.
4. All key-value pairs from a Kubernetes Secret or ConfigMap will be set as environment variables. This Secret/ConfigMap needs to be created before it is referenced in a function. Eg. '{{ secret:mysecret2 }}' where mysecret2 is the name of the Secret: or {{ configMap:myconfigmap }} where myconfigmap is the name of the ConfigMap.

envs:
- name: EXAMPLE1                            # (1) env variable directly from a value
  value: value
- name: EXAMPLE2                            # (2) env variable from a local environment value
  value: '{{ env:LOCAL_ENV_VALUE }}'
- name: EXAMPLE3                            # (3) env variable from a key in Secret
  value: '{{ secret:mysecret:key }}'
- name: EXAMPLE4                            # (3) env variable from a key in ConfigMap
  value: '{{ configMap:myconfigmap:key }}'
- value: '{{ secret:mysecret2 }}'           # (4) all key-value pairs in Secret as env variables
- value: '{{ configMap:myconfigmap2 }}'     # (4) all key-value pairs in ConfigMap as env variables

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.

labels

The labels field allows you to set labels on a deployed function. Labels can be set directly from a value or from a local environment value. Eg. '{{ env:USER }}', for more details see Local Environment Variables section.

labels:
- key: role                                # (1) label directly from a value
  value: backend
- key: author                              # (2) label from a local environment value
  value: '{{ env:USER }}'

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.

options

Options allows you to set specific configuration for the deployed function, allowing you to tweak Knative Service options related to autoscaling and other properties. If these options are not set, the Knative defaults will be used.

• scale
  • min: Minimum number of replicas. Must me non-negative integer, default is 0. See related Knative docs.
  • max: Maximum number of replicas. Must me non-negative integer, default is 0 - meaning no limit. See related Knative docs.
  • metric: Defines which metric type is watched by the Autoscaler. Could be concurrency (default) or rps. See related Knative docs.
  • target: Recommendation for when to scale up based on the concurrent number of incoming request. Defaults to options.resources.limits.concurrency when given. Can be float value greater than 0.01, default is 100. See related Knative docs.
  • utilization: Percentage of concurrent requests utilization before scaling up. Can be float value between 1 and 100, default is 70. See related Knative docs.
• resources
  • requests
    • cpu: A CPU resource request for the container with deployed function. See related Kubernetes docs.
    • memory: A memory resource request for the container with deployed function. See related Kubernetes docs.
  • limits
    • cpu: A CPU resource limit for the container with deployed function. See related Kubernetes docs.
    • memory: A memory resource limit for the container with deployed function. See related Kubernetes docs.
    • concurrency: Hard Limit of concurrent requests to be processed by a single replica. Can be integer value greater than or equal to 0, default is 0 - meaning no limit. See related Knative docs.

options:
  scale:
    min: 0
    max: 10
    metric: concurrency
    target: 75
    utilization: 75
  resources:
    requests:
      cpu: 100m
      memory: 128Mi
    limits:
      cpu: 1000m
      memory: 256Mi
      concurrency: 100

runtime

The language runtime for your function. For example python.

template

The source code template tailored for the invocation event that triggers your function. For example http for plain HTTP requests, event for CloudEvent triggered functions.

volumes

Kubernetes Secrets or ConfigMaps can be mounted to the function as a Kubernetes Volume accessible under specified path. Below you can see an example how to mount the Secret mysecret to the path /workspace/secret and the ConfigMap myconfigmap to the path /workspace/configmap. This Secret/ConfigMap needs to be created before it is referenced in a function.

volumes:
- secret: mysecret
  path: /workspace/secret
- configMap: myconfigmap
  path: /workspace/configmap

Local 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:

envs:
- name: API_KEY
  value: '{{ env:API_KEY }}'