Invoking an Oracle Function using the OCI Python SDK

Introduction

This example illustrates how to use the OCI Python SDK to invoke a function deployed to Oracle Functions. The OCI SDK includes support for a large number of OCI services but this example focuses specifically on Functions support. For an introduction to the OCI SDK please refer to the official documentation.

In this example we'll show how you can invoke a function using its name, the name of application it belongs to, the OCI compartment that contains the application, and the OCID of your tenancy. To do this we'll use the two Functions related API clients exposed by the OCI SDK:

• FunctionsManagementClient - is used for functions lifecycle management operations including creating, updating, and querying applications and functions
• FunctionsInvokeClient - is used specifically for invoking functions

Along with the two clients, the OCI SDK also provides a number of wrapper/handle objects like oci.identity.models.Compartment, oci.functions.models.Application, and oci.functions.models.Function. In the example, we navigate down the hierarchy from oci.identity.models.Compartment to oci.functions.models.Function and then once we have the desired oci.functions.models.Function we invoke is using the oci.functions.FunctionsInvokeClient.

Important Note: A Function's OCID and invoke endpoint will remain the same unless you delete the function or it's parent application. Once you get the oci.functions.models.Function, you should cache the function's OCID and invoke endpoint either in-memory or to an external data store and use the cached values for subsequent invocations.

For more information on code structure and API along with the data types please read code doc strings available for each method:

• get_compartment method
• get_app method
• get_function method

Prerequisites

This example invokes a function so we have to install the Fn CLI and create a target function:

1. Install/update the Fn CLI

   curl -LSs https://raw.githubusercontent.com/fnproject/cli/master/install | sh

2. Create a function to invoke

   Create a function using Golang Hello World Function

Install preview OCI Python SDK

1. Download and unzip the preview SDK

   unzip oci-python-sdk-2.2.11+preview.1.819.zip

2. Change into the correct directory

   cd oci-python-sdk

3. Virtualenv

   python3 -m venv .venv
   source .venv/bin/activate
   pip install oci-2.2.11+preview.1.819-py2.py3-none-any.whl

4. Clone this repository in a separate directory

   git clone https://github.com/denismakogon/fn-python-sdk-invoke.git

5. Change to the correct directory where you cloned the example:

   cd fn-python-sdk-invoke

Authentication

This example assumes the OCI config file is available on the machine where this client code will run. You can override the config defaults using the following environment variables:

• OCI_CONFIG_PATH for the OCI config file (default value: ~/.oci/config)
• OCI_CONFIG_PROFILE stands from the OCI config profile (default value: DEFAULT)

You can now invoke your function!

python invoke_function.py <compartment-name> <app-name> <function-name> <request payload>

Enable debug mode

Set environment variable:

export DEBUG=1
python invoke_function.py <compartment-name> <app-name> <function-name> <request payload>

or

DEBUG=1 python invoke_function.py <compartment-name> <app-name> <function-name> <request payload>

Example of invoking a function

1. Using "DEFAULT" oci config profile:

python invoke_function.py workshop helloworld-app helloworld-func-go '{"name":"foobar"}'
{"message":"Hello foobar"}

2. Using a non-DEFAULT profile name in oci config:

a) with payload:

OCI_CONFIG_PROFILE=workshop-devrel-profile python invoke_function.py workshop helloworld-app helloworld-func-go '{"name":"foobar"}'

b) without payload:

OCI_CONFIG_PROFILE=workshop-devrel-profile python invoke_function.py workshop helloworld-app helloworld-func-go '{}'

3. Invoking a Function inside a nested compartment:

a) with payload:

python invoke_function.py nested-ws nest-app go-fn {"name":"EMEA"}

b) without payload:

python invoke_function.py nested-ws nest-app go-fn '{}'

What if my function needs input in binary form?

You can use this TensorFlow based function as an example to explore the possibility of invoking a function using binary content. This function expects the image data (in binary form) as an input and returns what object that image resembles along with the percentage accuracy.

If you were to deploy the TensorFlow function, the command to invoke it using Fn CLI would be something like this:

cat test-som-1.jpeg | fn invoke fn-tensorflow-app classify

In this case, the test-som-1.jpeg image is being passed as an input to the function.

The programmatic (using python SDK) equivalent of this would look something like invoke_function_tf.py

Example of invoking a function with binary input

python invoke_function_tf.py <compartment-name> <app-name> <function-name> <image-file-path>

python invoke_function_tf.py workshop demo-app classify test-som-1.jpeg
This is a 'sombrero' Accuracy - 94%