Add a script to update docker images with docker compose

update_docker_images.sh

@@ -0,0 +1,108 @@
+#!/usr/bin/env bash
+# Usage: ./update_docker_images.sh [--prune] [--build] [compose-directory]
+# By default, pull images and update services without pruning or building.
+# WARNING: Pruning removes stopped containers, unused images, build cache,
+# and unused anonymous volumes.
+set -euo pipefail
+
+usage() {
+    printf 'Usage: %s [--prune] [--build] [compose-directory]\n' "$0"
+    printf '%s\n' \
+        '  --prune  Remove unused Docker resources before updating (including volumes).' \
+        '  --build  Build images with --pull before updating services.' \
+        '  -h, --help  Show this help.' \
+        'Default: pull images and update services; do not prune or build.'
+}
+
+prune=false
+build=false
+positional=()
+while (( $# )); do
+    case "$1" in
+        --prune) prune=true ;;
+        --build) build=true ;;
+        -h|--help) usage; exit 0 ;;
+        --) shift; positional+=("$@"); break ;;
+        -*) printf 'Unknown option: %s\n' "$1" >&2; usage >&2; exit 2 ;;
+        *) positional+=("$1") ;;
+    esac
+    shift
+done
+if (( ${#positional[@]} > 1 )); then
+    usage >&2
+    exit 2
+fi
+
+compose_root=${positional[0]:-/etc/docker/compose}
+if [[ ! -d "$compose_root" ]]; then
+    printf 'Compose directory not found: %s\n' "$compose_root" >&2
+    exit 1
+fi
+
+created_builder=
+cleanup() {
+    local status=$?
+    trap - EXIT
+    if [[ -n "$created_builder" ]]; then
+        if ! docker buildx rm "$created_builder"; then
+            printf 'Could not remove builder: %s\n' "$created_builder" >&2
+            if (( status == 0 )); then
+                status=1
+            fi
+        fi
+    fi
+    exit "$status"
+}
+trap cleanup EXIT
+trap 'exit 130' INT
+trap 'exit 143' TERM
+
+if "$prune"; then
+    docker system df
+    docker system prune -a --volumes -f
+    docker system df
+fi
+
+if "$build"; then
+    # Select an existing container builder, not merely check whether one exists.
+    # Capture the list separately so a failed Docker command stops the script.
+    builders=$(docker buildx ls --format '{{.Name}} {{.Driver}}')
+    builder=
+    while read -r name driver; do
+        if [[ "$driver" == docker-container ]]; then
+            builder=$name
+            break
+        fi
+    done <<< "$builders"
+    if [[ -z "$builder" ]]; then
+        # Bootstrap separately so cleanup can run if startup fails.
+        created_builder=$(docker buildx create \
+            --buildkitd-config /etc/docker/buildx/buildkit.toml \
+            --driver docker-container \
+            --driver-opt 'network=treehouse')
+        builder=$created_builder
+    fi
+
+    # Select the builder for this script without changing the user's default.
+    export BUILDX_BUILDER="$builder"
+    docker buildx inspect "$builder" --bootstrap
+fi
+
+for directory in "$compose_root"/*; do
+    [[ -d "$directory" ]] || continue
+    [[ -f "$directory/docker-compose.yml" ]] || continue
+    # Manually update Minecraft, so we're not always on the cutting edge
+    [[ "$directory" == *minecraft* ]] && continue
+
+    printf '\nUpdating %s\n' "$directory"
+    # A subshell restores the working directory even when a command fails.
+    (
+        cd -- "$directory"
+        docker compose pull
+        if "$build"; then
+            docker compose build --pull
+        fi
+        # Do not let Compose implicitly build images when starting services.
+        docker compose up -d --no-build
+    )
+done