Azure Functions

Floci-AZ emulates Azure Functions by spawning real Azure Functions runtime Docker containers on demand and proxying HTTP invocations to them.

Requirements

Docker daemon reachable at /var/run/docker.sock (bind-mounted into the floci-az container)
Internet access on first use to pull the runtime images

Supported Runtimes

Runtime	Image
`node`	`mcr.microsoft.com/azure-functions/node:4`
`python`	`mcr.microsoft.com/azure-functions/python:4`
`java`	`mcr.microsoft.com/azure-functions/java:4`
`dotnet`	`mcr.microsoft.com/azure-functions/dotnet-isolated:4`

Endpoint

http://localhost:4577/{accountName}-functions

Default account: devstoreaccount1

Management API

Apps

Method	Path	Description
`PUT`	`/admin/apps/{appName}`	Create or update a function app
`GET`	`/admin/apps/{appName}`	Get a function app
`GET`	`/admin/apps`	List all function apps
`DELETE`	`/admin/apps/{appName}`	Delete a function app and all its functions

Create app request body:

{
  "runtime": "python",
  "linuxFxVersion": "Python|3.12",
  "environment": {
    "MY_VAR": "hello"
  }
}

linuxFxVersion is optional. When set, floci-az selects the matching Azure Functions Linux image, such as mcr.microsoft.com/azure-functions/python:4-python3.12. The ARM-compatible Microsoft.Web/sites and Microsoft.Web/sites/{name}/config/web paths accept the same setting under properties.siteConfig.linuxFxVersion and properties.linuxFxVersion, respectively.

Functions

Method	Path	Description
`PUT`	`/admin/apps/{appName}/functions/{funcName}`	Deploy a function (ZIP upload)
`GET`	`/admin/apps/{appName}/functions/{funcName}`	Get function details
`GET`	`/admin/apps/{appName}/functions`	List functions in an app
`DELETE`	`/admin/apps/{appName}/functions/{funcName}`	Delete a function

Deploy function request body:

{
  "handler": "index.handler",
  "timeoutSeconds": 60,
  "zipBase64": "<base64-encoded ZIP>"
}

The ZIP must contain your function code in the Azure Functions v4 layout:

host.json
{funcName}/function.json
{funcName}/index.js   (or handler file for the runtime)

Invocation

Method	Path	Description
`GET` / `POST`	`/api/{appName}/{funcName}[?...]`	Invoke an HTTP-triggered function

Warm Container Pool

By default, floci-az keeps function containers warm after first use (LIFO pool, one per function). Containers are evicted after FLOCI_AZ_SERVICES_FUNCTIONS_CONTAINER_IDLE_TIMEOUT_SECONDS seconds of inactivity (default 300 s / 5 minutes).

To disable warm reuse and get a fresh container per invocation:

environment:
  FLOCI_AZ_SERVICES_FUNCTIONS_EPHEMERAL: "true"

Mocked Mode

Set mocked: true (default false) to run the Functions service without Docker:

environment:
  FLOCI_AZ_SERVICES_FUNCTIONS_MOCKED: "true"

In mocked mode the management plane (create app, deploy/list/get/delete function) works entirely from state and no runtime container is ever launched. Because user code cannot execute without the runtime container, invocations (POST api/{app}/{func}) return a synthetic 200 stub instead of running the function. Useful for tests and CI environments without a Docker daemon.

Environment Variable	Default	Description
`FLOCI_AZ_SERVICES_FUNCTIONS_MOCKED`	`false`	Mocked mode (management plane only, no Docker; invocations return a synthetic 200 stub)

Embedded DNS (Docker-in-Docker)

When floci-az is itself running inside Docker, it starts an embedded UDP/53 DNS server and injects it into every spawned function container. This lets function containers resolve custom hostnames (configured via floci-az.hostname or floci-az.dns.extra-suffixes) to floci-az's Docker-network IP — useful when functions connect to Blob Storage using a hostname-based endpoint rather than a raw IP.

On the host, no DNS setup is needed; the embedded server is a no-op.

Linux Native Docker — Firewall Note

On native Linux Docker (not Docker Desktop), function containers reach the host via host.docker.internal (automatically mapped to host-gateway). If you run UFW with the default INPUT DROP policy, invocations will time out. Fix:

sudo ufw allow in on docker0

This is not needed on Docker Desktop (macOS/Windows) or when floci-az runs inside Docker.