EVENT-DRIVEN TRIGGER EXAMPLE FOR CONTAINER REGISTRY

• High Level Overview
• Directory Structure
• Setup

 High Level Overview

This repo is to show an event-driven architecture with its simplest use case: pub-sub model. Azure Container Registry is one the publishers of the Event Grid, and we want to filter a specific event Image.Push. As event handler Azure Functions will pick up the event and process to send Slack notifications when an image pushed to Azure Container Registry.

 Directory Structure

📦newfuncs
 ┣ 📂ACRFuncs
 ┃ ┣ 📂.python_packages
 ┃ ┣ 📂AcrEventGridFunc
 ┃ ┃ ┣ 📜__init__.py
 ┃ ┃ ┣ 📜function.json
 ┃ ┃ ┗ 📜post.json
 ┃ ┣ 📜.funcignore
 ┃ ┣ 📜host.json
 ┃ ┗ 📜requirements.txt
 ┣ 📂img
 ┃ ┗ 📜TriggerPipeline.png
 ┣ 📜.gitignore
 ┣ 📜README.md
 ┗ 📜azure-pipelines.yml

Setup

Requirements

1. A webhook url: I used Slack Incoming Webhook Url

2. A pipeline to set up Azure Container Registry to send the events and Functions to handle the events subscribed to EventGrid.

Setup of Pipeline

To run this demo in your Azure subscription, you need these variables to be set up on Azure DevOps pipeline:

1. DevOps Pipeline

   Fork this repo and create a new pipeline referencing your fork. It will create pipeline from the yaml in the source code.

2. Azure Connectivity:

   Set up a Service Connection for Azure Subscription called : azureSubscription. As yaml reference as a variable it should be the same name.

3. Create variables for your pipeline:	Variable	Description
   acr_name	Name of Container Registry. For simplicity ACR will be created on the same resource group/location as other resources.
   event_subscription_name	The subscription to be created listening ACR and handled by the Azure Function.
   functionapp_name	Name of the FunctionApp to hold all the functions.
   function_name	For this repo, it should be the name of the folder ACRFuncs where the Python function code is located. Azure functions is opinionated about folder structure.
   region	The location of ACR, Resource Group, Azure Functions, Storage Account for Azure Functions will reference this location.
   resource_group_name	The name of the resource group, all resources for the demo will be in this resource group.
   slack_image_push_url	The webhook url for the Slack message to be pushed.
   storage_account_name	The globally unique storage account name for FunctionApp to store diagnostic logs.

Test

To test the notifications, you can use the script below. It creates an image and pushes to the registry.

echo FROM hello-world > Dockerfile
REGISTRY="<REGISTRY>"

count=1
az acr build --image demo/hello-world:v${count} \
    --registry $REGISTRY \
    --file Dockerfile .