How can I deploy a prepackaged Quarkus Azure Functions app - azure

Question

Quarkus Azure function apps currently rely on the Maven azure-functions-maven-plugin plugin to perform a deployment of the function. However, this means that I need to package the application source code and rebuild it with each deployment. This is not ideal, as I really want an immutable package that I can deploy, promote, and roll back without rebuilding.
Is there any way to deploy a prepackaged Quarkus app without the Maven plugin?

Answer 1

The reality is that Microsoft has done a poor job of supporting Java developers deploying to Azure functions. The requirement to recompile the app with each deployment, which is the only option available to you when using the Maven plugin, is an anti-pattern for repeatable and reliable deployments.
Digging through the source code of the Maven plugin eventually leads you to the RunFromBlobFunctionDeployHandler class, which uploads a ZIP file as a blob, creates a long lived SAS token, and then sets the WEBSITE_RUN_FROM_PACKAGE setting to the SAS URL.
To recreate this process, we first need a function.json file, which will redirect all requests to the Quarkus io.quarkus.azure.functions.resteasy.runtime.Function.run class. You can get this class by generating a sample Quarkus project, as documented here:
{
"scriptFile" : "../products-microservice-runner.jar",
"entryPoint" : "io.quarkus.azure.functions.resteasy.runtime.Function.run",
"bindings" : [ {
"type" : "httpTrigger",
"direction" : "in",
"name" : "req",
"route" : "{*path}",
"methods" : [ "GET", "POST", "HEAD", "PUT", "OPTIONS", "DELETE" ],
"dataType" : "binary",
"authLevel" : "ANONYMOUS"
}, {
"type" : "http",
"direction" : "out",
"name" : "$return"
} ]
}
You then need a host.json file, again generated by the sample Quarkus project:
{
"version": "2.0"
}
Once we build your Quarkus Azure function app, you'll have a self contained JAR file. In my case it was called products-microservice-runner.jar. The next step is to recreate the directory structure documented here:
rm -rf /tmp/octopubproductservice
mkdir /tmp/octopubproductservice
mkdir /tmp/octopubproductservice/octopubproductservice
cp target/products-microservice-runner.jar /tmp/octopubproductservice
cp azure-config/host.json /tmp/octopubproductservice
cp azure-config/function.json /tmp/octopubproductservice/octopubproductservice
pushd /tmp/octopubproductservice
zip -r $ZIP_FILE .
popd
This produces a ZIP file like this:
Now create the resource group, storage account, and function as documented here:
REGION=australiaeast
RESOURCE_GROUP=octopubproductservice
FUNCTION_NAME=octopubproductservice
STORAGE_ACCOUNT=octopubproductservice
STORAGE_SKU="Standard_LRS"
ZIP_FILE=product-service-azure.zip
CURRENT_DATE=$(date +%Y%m%d)
SAS_EXPIRY=$(date -d "$CURRENT_DATE +10 years" +%Y-%m-%d)
# Create a resource group
az group create --location $REGION --name $RESOURCE_GROUP
# Create a storage account
az storage account create --name $STORAGE_ACCOUNT --resource-group $RESOURCE_GROUP --sku $STORAGE_SKU
# Create a function app
az functionapp create \
--name $FUNCTION_NAME \
--resource-group $RESOURCE_GROUP \
--storage-account $STORAGE_ACCOUNT \
--consumption-plan-location $REGION \
--functions-version 4 \
--os-type linux \
--runtime java \
--runtime-version 11.0
Next upload the function package and generate an SAS token:
# Upload the function package
az storage blob upload \
--account-name $STORAGE_ACCOUNT \
--container-name java-functions-run-from-packages \
--name product-service-azure.zip \
--file /tmp/octopubproductservice/product-service-azure.zip \
--overwrite \
--auth-mode key
# Create a SAS key for the function package
URL=$(az storage blob generate-sas \
--account-name $STORAGE_ACCOUNT \
--container-name java-functions-run-from-packages \
--name product-service-azure.zip \
--permissions r \
--expiry $SAS_EXPIRY \
--auth-mode key \
--full-uri)
# The URL is quoted. We treat this as a JSON string, and use jq to return the raw string
FIXED_URL=$(echo $URL | jq -r '.')
Finally, set the WEBSITE_RUN_FROM_PACKAGE setting to the SAS URL, which is required when deploying Linux functions:
# The raw string is set as the WEBSITE_RUN_FROM_PACKAGE value, which indicates Azure
# must download the function from the URL.
az functionapp config appsettings set \
--name $FUNCTION_NAME \
--resource-group $RESOURCE_GROUP \
--settings "WEBSITE_RUN_FROM_PACKAGE=$FIXED_URL"
At that point your Quarkus app should be working.