A shell script to recursively remove podman containers that depend on an image. Useful for cleaning up images on NixOS

remove-containers.sh

#!/usr/bin/env bash

# Script to recursively remove podman images and their dependent containers
# Usage: ./podman_recursive_rm.sh <image_id_or_name> [max_iterations]

set -e

# Colors for output
RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
BLUE='\033[0;34m'
NC='\033[0m' # No Color

# Function to print colored output
log_info() { echo -e "${BLUE}[INFO]${NC} $1"; }
log_success() { echo -e "${GREEN}[SUCCESS]${NC} $1"; }
log_warning() { echo -e "${YELLOW}[WARNING]${NC} $1"; }
log_error() { echo -e "${RED}[ERROR]${NC} $1"; }

# Function to extract container ID from error message
extract_container_id() {
    local error_msg="$1"
    # Extract the container ID from the error message
    # Pattern matches 64-char or 12-char hex strings (full or short container IDs)
    echo "$error_msg" | grep -oE '[a-f0-9]{64}|[a-f0-9]{12}' | head -n1
}

# Main recursive removal function
recursive_remove() {
    local image_id="$1"
    local max_iterations="$2"
    local iteration=1

    log_info "Starting recursive removal of image: $image_id (max iterations: $max_iterations)"

    while [[ $iteration -le $max_iterations ]]; do
        log_info "=== Iteration $iteration/$max_iterations ==="

        # Try to remove the image
        log_info "Attempting to remove image: $image_id"
        local output
        local exit_code=0

        output=$(podman image rm "$image_id" 2>&1) || exit_code=$?

        if [[ $exit_code -eq 0 ]]; then
            log_success "Successfully removed image: $image_id"
            echo "$output"
            return 0
        fi

        # Check if the error is about container dependencies
        if echo "$output" | grep -q "image.*used by\|image is in use by a container"; then
            log_warning "Image is in use by containers"
            echo "$output"

            # Extract container ID from error message
            local container_id
            container_id=$(extract_container_id "$output")

            if [[ -n "$container_id" ]]; then
                log_info "Found dependent container: $container_id"
                log_info "Removing container: $container_id"

                if podman container rm "$container_id"; then
                    log_success "Successfully removed container: $container_id"
                else
                    log_error "Failed to remove container: $container_id"
                    return 1
                fi
            else
                log_error "Could not extract container ID from error message"
                return 1
            fi
        else
            log_error "Image removal failed with error:"
            echo "$output"
            return $exit_code
        fi

        ((iteration++))
    done

    log_error "Failed to remove image after $max_iterations iterations"
    return 1
}

# Function to show usage
show_usage() {
    echo "Usage: $0 <image_id_or_name> [max_iterations]"
    echo ""
    echo "Arguments:"
    echo "  image_id_or_name    Image ID or name to remove"
    echo "  max_iterations      Maximum iterations (default: 10)"
    echo ""
    echo "Examples:"
    echo "  $0 nginx:latest"
    echo "  $0 3c7c1348fe6e 5"
    echo "  $0 myimage:v1.0"
}

# Main script
main() {
    local image_id="$1"
    local max_iterations="${2:-10}"

    # Validate arguments
    if [[ -z "$image_id" ]]; then
        log_error "Image ID or name is required"
        show_usage
        exit 1
    fi

    if [[ "$image_id" == "-h" || "$image_id" == "--help" ]]; then
        show_usage
        exit 0
    fi

    if ! [[ "$max_iterations" =~ ^[0-9]+$ ]] || [[ "$max_iterations" -lt 1 ]]; then
        log_error "Invalid iteration count: $max_iterations"
        exit 1
    fi

    # Check if podman is available
    if ! command -v podman &> /dev/null; then
        log_error "podman command not found"
        exit 1
    fi

    # Check if image exists
    if ! podman image exists "$image_id" 2>/dev/null; then
        log_error "Image does not exist: $image_id"
        exit 1
    fi

    log_info "Configuration: Image=$image_id, Max iterations=$max_iterations"

    # Run the recursive removal
    if recursive_remove "$image_id" "$max_iterations"; then
        log_success "Image and dependent containers removed successfully!"
        exit 0
    else
        log_error "Failed to remove image and/or containers"
        exit 1
    fi
}

# Run main function with all arguments
main "$@"