#!/usr/bin/env bash
###############################################################################
### Docker Stack Backup Script
### Created by Charlie Silverman - ackitsme3@gmail.com
###############################################################################
### Version: 1.1.3
### Updated: 2026-08-05
### Purpose:  Backs up all docker stacks in a given directory to Restic bucket
###############################################################################
### Requirements:
### Restic environment file:  /root/.restic-env
### File format:
###     export AWS_ACCESS_KEY_ID="[S3 Bucket Access Key ID]"
###     export AWS_SECRET_ACCESS_KEY="[S3 Secret Access Key]"
###     export RESTIC_REPOSITORY="Restic repository URL"
###     export RESTIC_PASSWORD_FILE="Filepath to text file with restic password"
### Exception list:  Optionally store a list of exceptions in the file
###                  dockerbackup-exception.list in the same directory
###                  as this file.  File should be one entry per line.
###                  Each entry can contain wildcards if neeeded.
###############################################################################
# Version History:
# 1.0.0 - Initial build
# 1.1.0 - Added exception list via text file
# 1.1.1 - Added snapshot size to log
# 1.1.2 - Added aggregate backup size to end of log
# 1.1.3 - Added GiB to total backup size information

set -Eeuo pipefail

###############################################################################
# Configuration
###############################################################################

COMPOSE_ROOT="/home/ackitsme/docker"
LOG_DIR="/home/ackitsme/docker/backuplogs"
LOG_FILE="${LOG_DIR}/docker-backup_$(date +%Y%m%d-%H%M%S).log"

# Restic repository configuration
export RESTIC_REPOSITORY="s3:https://s3.us-west-004.backblazeb2.com/ackitsbucket/docker"
export RESTIC_ENV_FILE="/root/.restic-env"

# Load Restic environment
source $RESTIC_ENV_FILE

HOSTNAME_SHORT="$(hostname -s)"
TIMESTAMP="$(date +%Y%m%d-%H%M%S)"

# Load exceptions, if any
if [ -f "dockerbackup-exception.list" ]; then
   mapfile -t SKIP_PROJECTS < dockerbackup-exception.list
fi


###############################################################################
# Functions
###############################################################################

## Log to screen and log file
log() {
   local message="[$(date '+%F %T')] $*"

   echo "$message"
   echo "$message" >> "$LOG_FILE"
}

## Check if specified project is in the exception list
should_skip() {
    local project="$1"

    for pattern in "${SKIP_PROJECTS[@]}"; do
        if [[ "$project" == $pattern ]]; then
            return 0
        fi
    done

    return 1
}

## Check if docker container is running
is_container_running() {
    local container_name="$1"

    docker inspect -f '{{.State.Running}}' "$container_name" 2>/dev/null | grep -q '^true$'
}

## Restart composer stack
restart_stack() {

    local compose_dir="$1"

    log "Restarting stack: ${compose_dir}"

    (
        sudo -u ackitsme docker compose up -d
        su - ackitsme -c "cd ${compose_dir};docker compose up -d"

    ) || log "WARNING: Failed to restart stack ${compose_dir}"
}

###############################################################################
# Verify Requirements
###############################################################################

for cmd in docker restic tar gzip; do
    command -v "$cmd" >/dev/null 2>&1 || {
        echo "Missing required command: $cmd"
        exit 1
    }
done

###############################################################################
# Locate Compose Files
###############################################################################

mapfile -t COMPOSE_FILES < <(
    find "$COMPOSE_ROOT" \
        \( -name "docker-compose.yml" \
        -o -name "docker-compose.yaml" \
        -o -name "compose.yml" \
        -o -name "compose.yaml" \) \
        | sort
)

if [ "${#COMPOSE_FILES[@]}" -eq 0 ]; then
    log "No compose files found."
    exit 0
fi

###############################################################################
# Process Each Compose Project
###############################################################################

total_size=0

for compose_file in "${COMPOSE_FILES[@]}"; do

    compose_dir="$(dirname "$compose_file")"
    project_name="$(basename "$compose_dir")"

    if should_skip "$project_name"; then
        log "Skipping project: ${project_name}"
        continue
    fi

    log "=================================================="
    log "Processing project: ${project_name}"
    log "Compose file: ${compose_file}"
    log "=================================================="

    STAGING_DIR="/tmp/docker-backup-${project_name}-${TIMESTAMP}"

    mkdir -p \
        "${STAGING_DIR}/images" \
        "${STAGING_DIR}/volumes" \
        "${STAGING_DIR}/metadata"

    ###################################################
    # Gather Information Before Shutdown
    ###################################################

    cd "$compose_dir"

    docker compose config --images \
        | sort -u \
        > "${STAGING_DIR}/metadata/images.list" || true

    docker compose ps -q \
        > "${STAGING_DIR}/metadata/containers.list" || true

    ###################################################
    # Determine Volumes Used By Containers
    ###################################################

    > "${STAGING_DIR}/metadata/volumes.list"

    while read -r container_id; do

        [ -z "$container_id" ] && continue

        docker inspect "$container_id" \
            --format '{{range .Mounts}}{{if eq .Type "volume"}}{{.Name}}{{println}}{{end}}{{end}}'

    done < "${STAGING_DIR}/metadata/containers.list" \
        | sort -u \
        > "${STAGING_DIR}/metadata/volumes.list"

    ###################################################
    # Stop Stack
    ###################################################

    log "Stopping stack..."

    docker compose down --timeout 60

    ###################################################
    # Backup Compose Files
    ###################################################

    log "Backing up compose files..."

    tar -czf \
        "${STAGING_DIR}/${project_name}-compose.tar.gz" \
        -C "$(dirname "$compose_dir")" \
        "$(basename "$compose_dir")"

    ###################################################
    # Backup Images
    ###################################################

    log "Backing up images..."

    while read -r image; do

        [ -z "$image" ] && continue

        if docker image inspect "$image" >/dev/null 2>&1; then

            safe_name=$(echo "$image" | sed 's#[/:]#_#g')

            log "Saving image: $image"

            docker save "$image" \
                | gzip \
                > "${STAGING_DIR}/images/${safe_name}.tar.gz"
        fi

    done < "${STAGING_DIR}/metadata/images.list"

    ###################################################
    # Backup Volumes
    ###################################################

    log "Backing up volumes..."

    while read -r volume; do

        [ -z "$volume" ] && continue

        log "Saving volume: $volume"

        docker run --rm \
            -v "${volume}:/source:ro" \
            -v "${STAGING_DIR}/volumes:/backup" \
            alpine \
            tar -czf "/backup/${volume}.tar.gz" -C /source .

    done < "${STAGING_DIR}/metadata/volumes.list"

    ###################################################
    # Metadata
    ###################################################

    docker image ls \
        > "${STAGING_DIR}/metadata/docker-images.txt"

    docker volume ls \
        > "${STAGING_DIR}/metadata/docker-volumes.txt"

    docker network ls \
        > "${STAGING_DIR}/metadata/docker-networks.txt"

    docker compose config \
        > "${STAGING_DIR}/metadata/rendered-compose.yml" || true

    ###################################################
    # Restart Stack
    ###################################################

    restart_stack "${compose_dir}"

    ###################################################
    # Restic Backup
    ###################################################

    log "Uploading project backup to Restic..."

    restic backup \
        "${STAGING_DIR}" \
        --tag docker \
        --tag compose \
        --tag "${project_name}" \
        --tag "${HOSTNAME_SHORT}"

    ###################################################
    # Get backup size
    ###################################################
        lastsnap=`restic ls latest`
        lastsnapid=$(echo "$lastsnap" | awk '{print $2}')
        snapdata=`restic snapshots $lastsnapid`
        snapnum=$(echo $snapdata | awk '{print $14}')
        snapsu=$(echo $snapdata | awk '{print $15}')
        case "$snapsu" in
                "TiB")
                        snapnum=$(echo "scale=2;$snapnum * 1024" | bc)
                        ;;
                "MiB")
                        snapnum=$(echo "scale=2;$snapnum / 1024" | bc)
                        ;;
        esac
        snapnum=$(printf "%.2f\n" "$snapnum")

    ###################################################
    # Cleanup Local Backup
    ###################################################

    rm -rf "${STAGING_DIR}"

    log "Project complete: ${project_name} ${snapnum} GiB"
    log ""
    total_size=$(bc <<< "$total_size + $snapnum")
done

###############################################################################
# Retention Policy
###############################################################################

log "Applying Restic retention policy..."

restic forget \
    --keep-daily 7 \
    --keep-weekly 4 \
    --keep-monthly 12 \
    --prune

log "All compose projects backed up successfully."
log "Total Backup Size: $total_size GiB"