Create an Azure Function that connects to an Azure Cosmos DB

This Azure Functions sample script creates a function app and connects the function to an Azure Cosmos DB database. It makes the connection using an Azure Cosmos DB endpoint and access key that it adds to app settings. The created app setting that contains the connection can be used with an Azure Cosmos DB trigger or binding.

If you don't have an Azure subscription, create a trial account before you begin.

Prerequisites

You can use the local Azure CLI.

Sample script

Run the script

#!/bin/bash

# <FullScript>
# Function app and storage account names must be unique.

# Variable block
let "randomIdentifier=$RANDOM*$RANDOM"
location="chinanorth2"
resourceGroup="msdocs-azure-functions-rg-$randomIdentifier"
tag="create-function-app-connect-to-cosmos-db"
storage="msdocsaccount$randomIdentifier"
functionApp="msdocs-serverless-function-$randomIdentifier"
skuStorage="Standard_LRS"
functionsVersion="4"

# Create a resource group
echo "Creating $resourceGroup in "$location"..."
az group create --name $resourceGroup --location "$location" --tags $tag

# Create a storage account for the function app. 
echo "Creating $storage"
az storage account create --name $storage --location "$location" --resource-group $resourceGroup --sku $skuStorage

# Create a serverless function app in the resource group.
echo "Creating $functionApp"
az functionapp create --name $functionApp --resource-group $resourceGroup --storage-account $storage --consumption-plan-location "$location" --functions-version $functionsVersion

# Create an Azure Cosmos DB database account using the same function app name.
echo "Creating $functionApp"
az cosmosdb create --name $functionApp --resource-group $resourceGroup

# Get the Azure Cosmos DB connection string.
endpoint=$(az cosmosdb show --name $functionApp --resource-group $resourceGroup --query documentEndpoint --output tsv)
echo $endpoint

key=$(az cosmosdb keys list --name $functionApp --resource-group $resourceGroup --query primaryMasterKey --output tsv)
echo $key

# Configure function app settings to use the Azure Cosmos DB connection string.
az functionapp config appsettings set --name $functionApp --resource-group $resourceGroup --setting CosmosDB_Endpoint=$endpoint CosmosDB_Key=$key
# </FullScript>

# echo "Deleting all resources"
# az group delete --name $resourceGroup -y

Clean up resources

Use the following command to remove the resource group and all resources associated with it using the az group delete command - unless you have an ongoing need for these resources. Some of these resources may take a while to create, as well as to delete.

az group delete --name $resourceGroup

Sample reference

Command Notes
az group create Create a resource group with location
az storage accounts create Create a storage account
az functionapp create Creates a function app in the serverless Consumption plan.
az cosmosdb create Create an Azure Cosmos DB database.
az cosmosdb show Gets the database account connection.
az cosmosdb list-keys Gets the keys for the database.
az functionapp config appsettings set Sets the connection string as an app setting in the function app.

Next steps

For more information on the Azure CLI, see Azure CLI documentation.

More Azure Functions CLI script samples can be found in the Azure Functions documentation.