docker Module

Docker and container management utilities.

Import

from fscm.modules import docker

Functions

get_compose_command

Find the docker-compose or podman-compose command.

compose_cmd = docker.get_compose_command()
# Returns: "docker compose", "docker-compose", "podman-compose", or None

Checks for (in order): 1. podman-compose 2. docker compose (v2) 3. docker-compose (v1)

Returns: Command string or None if not found.

---

volume_exists

Check if a container volume exists.

if docker.volume_exists("myapp_data"):
    print("Volume exists")

Parameters:

Name	Type	Description
name	str	Volume name

Returns: bool

---

create_volume

Create a container volume.

docker.create_volume("myapp_data")

Parameters:

Name	Type	Description
name	str	Volume name

Returns: ChangeList

---

container_exists

Check if a container exists (running or stopped).

if docker.container_exists("myapp"):
    print("Container exists")

Parameters:

Name	Type	Description
name	str	Container name

Returns: bool

---

is_container_up

Check if a container is running.

if docker.is_container_up("myapp"):
    print("Container is running")
else:
    print("Container is stopped or doesn't exist")

Parameters:

Name	Type	Description
name	str	Container name

Returns: bool

---

image_exists

Check if a container image exists locally.

if docker.image_exists("nginx"):
    print("Image is available")

Parameters:

Name	Type	Description
name	str	Image name

Returns: bool

Configuration

The container command (docker or podman) is configured via settings:

import fscm

# Use podman instead of docker
fscm.settings.container_cmd = "podman"

Examples

Ensure Container Running

import fscm
from fscm.modules import docker

def ensure_container_running(name: str, image: str, ports: dict = None):
    """Ensure a container is running."""
    if docker.is_container_up(name):
        return  # Already running

    # Build run command
    cmd = f"docker run -d --name {name}"

    if ports:
        for host, container in ports.items():
            cmd += f" -p {host}:{container}"

    cmd += f" {image}"

    if docker.container_exists(name):
        # Remove stopped container
        fscm.run(f"docker rm {name}")

    fscm.run(cmd)

# Usage
ensure_container_running("redis", "redis:alpine", {"6379": "6379"})

Docker Compose Workflow

import fscm
from fscm.modules import docker

def deploy_compose_stack(compose_dir: str):
    """Deploy a docker-compose stack."""
    compose_cmd = docker.get_compose_command()
    if not compose_cmd:
        raise RuntimeError("Docker Compose not found")

    # Pull latest images
    fscm.run(f"{compose_cmd} pull", cwd=compose_dir)

    # Start services
    fscm.run(f"{compose_cmd} up -d", cwd=compose_dir)

    # Show status
    fscm.run(f"{compose_cmd} ps", cwd=compose_dir)

# Usage
deploy_compose_stack("/opt/mystack")

Volume Management

from fscm.modules import docker

def setup_persistent_volumes():
    """Create required volumes."""
    volumes = ["postgres_data", "redis_data", "app_uploads"]

    for vol in volumes:
        if not docker.volume_exists(vol):
            docker.create_volume(vol)
            print(f"Created volume: {vol}")
        else:
            print(f"Volume exists: {vol}")

setup_persistent_volumes()

Health Check

import fscm
from fscm.modules import docker

def check_stack_health(containers: list[str]):
    """Check if all containers are running."""
    all_healthy = True

    for name in containers:
        if docker.is_container_up(name):
            print(f"  {name}: UP")
        else:
            print(f"  {name}: DOWN")
            all_healthy = False

    return all_healthy

# Usage
containers = ["nginx", "app", "postgres", "redis"]
if not check_stack_health(containers):
    print("Some containers are not running!")