Add step parameters support

Author: Patrick J. McNerthney

README.md

@@ -214,6 +214,7 @@ The BaseComposite also provides access to the following Crossplane Function leve
 | self.request | Message | Low level direct access to the RunFunctionRequest message |
 | self.response | Message | Low level direct access to the RunFunctionResponse message |
 | self.logger | Logger | Python logger to log messages to the running function stdout |
+| self.parameters | Map | The configured step parameters |
 | self.ttl | Integer | Get or set the response TTL, in seconds |
 | self.credentials | Credentials | The request credentials |
 | self.context | Map | The response context, initialized from the request context |
@@ -552,6 +553,41 @@ Secrets can also be used in an identical manner as ConfigMaps by enabling the
 `--packages-secrets` command line option. Secrets permissions need to be
 added to the above RBAC configuration.
 
+## Step Parameters
+
+Step specific parameters can be configured to be used by the composite
+implementation. This is useful when setting the composite to the python class.
+For example:
+```yaml
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  namespace: crossplane-system
+  name: example-pythonic
+  labels:
+    function-pythonic.package: example.pythonic
+data:
+  features.py: |
+    from crossplane.pythonic import BaseComposite
+    class GreetingComposite(BaseComposite):
+        def compose(self):
+            cm = self.resources.ConfigMap('v1', 'ConfigMap')
+            cm.data.greeting = f"Hello, {self.parameters.who}!"
+```
+```yaml
+    ...
+    - step: pythonic
+    functionRef:
+      name: function-pythonic
+    input:
+      apiVersion: pythonic.fn.fortra.com/v1alpha1
+      kind: Composite
+      parameters:
+        who: World
+      composite: example.pythonic.features.GreetingComposite
+    ...
+```
+
 ## Filing System Packages
 
 Composition Composite implementations can be coded in a stand alone python files

crossplane/pythonic/composite.py

@@ -24,6 +24,7 @@ def __init__(self, request, logger):
         )
         self.response = protobuf.Message(None, 'response', response.DESCRIPTOR, response)
         self.logger = logger
+        self.parameters = self.request.input.parameters
         self.credentials = Credentials(self.request)
         self.context = self.response.context
         self.environment = self.context['apiextensions.crossplane.io/environment']

package/input-definition.yaml

@@ -29,6 +29,9 @@ spec:
           step:
             type: string
             description: Optional step name used in logging
+          parameters:
+            type: object
+            x-kubernetes-preserve-unknown-fields: true
           composite:
             type: string
             description: 'A Python module that defines a class with the signature: class Composite(BaseComposite)'