Serverless audio transcription with Python on IBM Cloud

This repository contains everything needed to deploy a serverless Python function for processing and transcribing audio at IBM Cloud.

Requirements

Tools

• IBM Cloud CLI (ibmcloud): https://cloud.ibm.com/docs/cli?topic=cli-install-ibmcloud-cli
• OpenWhisk plugin for IBM Cloud CLI (wsk): ibmcloud plugin install cloud-functions
• [OPTIONAL] Docker (docker): https://hub.docker.com/?overlay=onboarding
• [OPTIONAL] cURL (curl)

IBM Cloud services used

• Watson STT (speech-to-text): https://cloud.ibm.com/catalog/services/speech-to-text

[OPTIONAL] building a custom Docker image for your serverless function

IBM Cloud Functions accepts any kind of Docker image as custom runtime for your functions, albeit you can only use images from public registries, such as an image that is publicly available on Docker Hub. Private registries are not supported.

In this example we will be using a custom Dockerfile with some Python libraries installed. This Docker image is publicly hosted on vnderlev/custom-py-wsk:v5, so building it is not required.

Nevertheless, to build an image and deploy it on Docker Hub you need to run the following commands:

login into Docker Hub

docker login -u <dockerhub_username> -p <dockerhub_password>

building a Docker image from a Dockerfile

docker build <dockerfile_directory> -t <dockerhub_username>/<repository_name>:<tag_name>

pushing a Docker image to Docker Hub

docker push <dockerhub_username>/<repo_name>:<tag_name>

Managing Web actions with the IBM Cloud CLI

The IBM Cloud CLI plugin for working with OpenWhisk allow us to use "wsk" commands to create, deploy and debug any kind of serverless function into IBM Cloud. Below some useful commands are presented.

Deleting an existing Web action

ibmcloud wsk action delete <action_name>

Creating a raw Web action on IBM Cloud using a custom Dockerfile

ibmcloud wsk action create <action_name> --docker <dockerhub_username>/<image_name> <src_code_file> --web raw

Updating a raw Web action on IBM Cloud using a custom Dockerfile

ibmcloud wsk action update <action_name> --docker <dockerhub_username>/<image_name> <src_code_file> --web raw

Extracting the URL endpoint of the encapsulated serverless function

ibmcloud wsk action get <action_name> --url

Testing the deployed Web action with cURL

curl -F text=foo -F audio=@audio_sample.flac <action_url_endpoint>.json

Listing previous OpenWhisk activations

ibmcloud wsk activation list

You can get details about a specific activation record that resulted from an action invocation by running the following command. Replace <activation_id> with the id of the activation.

ibmcloud wsk activation get <activation_id>

Read more at: https://cloud.ibm.com/docs/openwhisk?topic=openwhisk-actions_web#actions_web_example