Add documentation on how to run

Author: Patrick J. McNerthney

README.md

@@ -43,6 +43,17 @@ function-go-templating examples implemented using function-pythonic.
 The [eks-cluster](./examples/eks-cluster/composition.yaml) example is a good
 complex example creating the entire vpc structure needed for an EKS cluster.
 
+## Installing function-pythonic
+
+```yaml
+apiVersion: pkg.crossplane.io/v1
+kind: Function
+metadata:
+  name: function-pythonic
+spec:
+  package: ghcr.io/fortra/function-pythonic:v0.0.3
+```
+
 ## Managed Resource Dependencies
 
 function-pythonic automatically handles dependencies between managed resources.
@@ -259,10 +270,10 @@ spec:
         self.status.composite = 'Hello, World!'
 ```
 
-## Installing Python Packages
+## Install Additional Python Packages
 
 function-pythonic supports a `--pip-install` command line option which will run pip install
-with the configured pip install command. For example, the following DeploymentRuntimeConfig:
+with the configured pip install command. For example:
 ```yaml
 apiVersion: pkg.crossplane.io/v1beta1
 kind: DeploymentRuntimeConfig
@@ -280,3 +291,27 @@ spec:
             - --pip-install
             - --quiet aiobotocore==2.23.2
 ```
+
+## Enable Oversize Protos
+
+The Protobuf python package used by function-pythonic limits the depth of yaml
+elements and the total size of yaml parsed. This results in a limit of approximately
+30 levels of nested yaml fields. This check can be disabled using the `--allow-oversize-protos`
+command line option. For example:
+
+```yaml
+apiVersion: pkg.crossplane.io/v1beta1
+kind: DeploymentRuntimeConfig
+metadata:
+  name: function-pythonic
+spec:
+  deploymentTemplate:
+    spec:
+      template:
+        spec:
+          containers:
+          - name: package-runtime
+            args:
+            - --debug
+            - --allow-oversize-protos
+```

function/main.py

@@ -38,13 +38,23 @@ def main():
         '--pip-install',
         help='Pip install command to install additional Python packages.'
     )
+    parser.add_argument(
+        '--allow-oversize-protos',
+        action='store_true',
+        help='Allow oversized protobuf messages'
+    )
     args = parser.parse_args()
     if not args.tls_certs_dir:
         args.tls_certs_dir = os.getenv('TLS_SERVER_CERTS_DIR')
 
     if args.pip_install:
         pip._internal.cli.main.main(['install', *shlex.split(args.pip_install)])
 
+    if args.allow_oversize_protos:
+        from google.protobuf.internal import api_implementation
+        if api_implementation._c_module:
+            api_implementation._c_module.SetAllowOversizeProtos(True)
+
     logging.configure(logging.Level.DEBUG if args.debug else logging.Level.INFO)
     runtime.serve(
         function.fn.FunctionRunner(),

function/protobuf.py

@@ -224,6 +224,8 @@ def __getitem__(self, key):
                     value = RepeatedMessage(self, key, self._field.message_type, value, self._readOnly)
             else:
                 value = Message(self, key, self._field.message_type, value, self._readOnly)
+        elif self._field.type == self._field.TYPE_BYTES and isinstance(value, bytes):
+            value = value.decode('utf-8')
         self._cache[key] = value
         return value
 
@@ -308,8 +310,8 @@ def __setitem__(self, key, message):
             self._messages = self._parent._create_child(self._key)
         if isinstance(message, Message):
             message = message._message
-        if isinstance(message, str) and self._field.type == self._field.TYPE_BYTES:
-            message = message.encode()
+        if self._field.type == self._field.TYPE_BYTES and isinstance(message, str):
+            message = message.encode('utf-8')
         self._messages[key] = message
         self._cache.pop(key, None)
 

pyproject.toml

@@ -44,7 +44,7 @@ type = "virtual"
 path = ".venv-default"
 dependencies = ["ipython==9.1.0"]
 [tool.hatch.envs.default.scripts]
-development = "python function/main.py --insecure --debug"
+development = "python function/main.py --insecure --debug --allow-oversize-protos"
 
 [tool.hatch.envs.lint]
 type = "virtual"