function-environment-configs

[!WARNING] This function relies on functionalities only available in Crossplane 1.15 and later. It will not work with earlier versions.

[!IMPORTANT]
This function is meant to replace native Composition Environment (--enable-environment-configs), see below for more details.

This composition function allows you to request EnvironmentConfigs, merge them in the requested order and return inject the computed environment into the Context at a well-known key, apiextensions.crossplane.io/environment, so that other functions such as function-patch-and-transform can access it.

Using this function

See the example directory for examples that you can run locally using the Crossplane CLI:

$ crossplane beta render \
  --extra-resources example/environmentConfigs.yaml \
  --include-context \
  example/xr.yaml example/composition.yaml example/functions.yaml

To validate the rendered output, you can use the crossplane beta validate command:

$ crossplane beta render \
  --extra-resources example/environmentConfigs.yaml \
  --include-full-xr \
  example/xr.yaml example/composition.yaml example/functions.yaml | crossplane beta validate example -

See the composition functions documentation to learn more about crossplane beta render.

Migration from native Composition Environment

Crossplane 1.18 dropped native Composition Environment, meaning spec.environment and *Environment patches were removed, while EnvironmentConfig as a resource was promoted to Beta.

crossplane beta convert pipeline-composition has been updated to automatically migrate Compositions using those fields to this function.

A manual migration can be performed moving the following fields from a Composition spec to this function's Input:

• spec.environment.environmentConfigs -> spec.environmentConfigs
• spec.environment.defaultData -> spec.defaultData
• spec.environment.policy.resolution -> spec.policy.resolution

spec.environment.policy.resolve is not configurable at the moment, defaulting to policy Always.

spec.environment.patches and resources' *Environment patches will have to be moved to function-patch-and-transform's input.

The diagram below shows what part of the usual Composition is replaced by this function and how it fits with other functions:

Migration Example

Given an example Resource-mode Composition:

[!WARNING] The example below is using the old native Composition Environment, which was dropped in Crossplane 1.18.

The above can be converted to use this function and function-patch-and-transform as follows:

apiVersion: apiextensions.crossplane.io/v1
kind: Composition
metadata:
   name: foo
spec:
  compositeTypeRef:
    apiVersion: example.crossplane.io/v1
    kind: XR
  mode: Pipeline
  pipeline:
  - step: environmentConfigs
    functionRef:
      name: function-environment-configs
    input:
      apiVersion: environmentconfigs.fn.crossplane.io/v1beta1
      kind: Input
      spec:
        environmentConfigs:
        - type: Reference
          ref:
            name: example-config
    # the environment is be passed to the next function in the pipeline
    # as part of the context
  - step: patch-and-transform
    # function-patch-and-transform knows it has to look for the environment in the
    # context at "apiextensions.crossplane.io/environment"
    functionRef:
      name: function-patch-and-transform
    input:
      apiVersion: pt.fn.crossplane.io/v1beta1
      kind: Resources
      environment:
        patches:
        # So you can then use it in all your patches:
        # - Env -> XR
        - type: ToCompositeFieldPath
          fromFieldPath: "someFieldInTheEnvironment"
          toFieldPath: "status.someFieldFromTheEnvironment"
        # - XR -> Env
        - type: FromCompositeFieldPath
          fromFieldPath: "spec.someFieldInTheXR"
          toFieldPath: "someFieldFromTheXR"
        resources:
        - name: bucket
          base:
            apiVersion: s3.aws.upbound.io/v1beta1
            kind: Bucket
            spec:
              forProvider:
                region: us-east-2
          patches:
          # - Env -> Resource
          - type: FromEnvironmentFieldPath
            fromFieldPath: "someFieldInTheEnvironment"
            toFieldPath: "spec.forProvider.someFieldFromTheEnvironment"
          # - Resource -> Env
          - type: ToEnvironmentFieldPath
            fromFieldPath: "status.someOtherFieldInTheResource"
            toFieldPath: "someOtherFieldInTheEnvironment"

Consuming environment from Context-aware functions

This function just merges selected EnvironmentConfigs into the Context at a well-known key, apiextensions.crossplane.io/environment, therefore any Context-aware function can access it.

For example, using function-go-templating:

apiVersion: apiextensions.crossplane.io/v1
kind: Composition
metadata:
   name: foo
spec:
  compositeTypeRef:
    apiVersion: example.crossplane.io/v1
    kind: XR
  mode: Pipeline
  pipeline:
  - step: environmentConfigs
    functionRef:
      name: function-environment-configs
    input:
      apiVersion: environmentconfigs.fn.crossplane.io/v1beta1
      kind: Input
      spec:
        environmentConfigs:
        - type: Reference
          ref:
            name: example-config
    # the environment is be passed to the next function in the pipeline
    # as part of the context
  - step: go-templating
    functionRef:
      name: function-go-templating
    input:
      apiVersion: gotemplating.fn.crossplane.io/v1beta1
      kind: GoTemplate
      source: Inline
      inline:
        template: |
          ---
          apiVersion: example.crossplane.io/v1
          kind: XR
          status:
            fromEnv: {{ index .context "apiextensions.crossplane.io/environment" "complex" "c" "d" }}

Developing this function

This function uses Go, Docker, and the Crossplane CLI to build functions.

# Run code generation - see input/generate.go
$ go generate ./...

# Run tests - see fn_test.go
$ go test ./...

# Build the function's runtime image - see Dockerfile
$ docker build . --tag=runtime

# Build a function package - see package/crossplane.yaml
$ crossplane xpkg build -f package --embed-runtime-image=runtime