Docker cleanup script

docker_cleanup.sh

#!/usr/bin/env bash
set -euo pipefail

# -----------------------------------------------
# Usage:
#   ./prune-old.sh            # prune only resources older than today (i.e. created before 00:00 of current date)
#   ./prune-old.sh -a|--all   # prune everything, regardless of age
# -----------------------------------------------

FULL_PRUNE=false

# Parse arguments
while [[ $# -gt 0 ]]; do
    case "$1" in
        -a|--all)
            FULL_PRUNE=true
            shift
            ;;
        -*)
            echo "Unknown option: $1"
            echo "Usage: $0 [-a|--all]"
            exit 1
            ;;
        *)
            echo "Usage: $0 [-a|--all]"
            exit 1
            ;;
    esac
done

if [ "$FULL_PRUNE" = true ]; then
    echo "→ Performing full prune of all stopped containers, unused images, and builder cache."
    docker container prune -f
    docker image prune -af
    docker builder prune -af
    exit 0
fi

# -------------------------------------------------------------
# Compute “seconds since midnight” so we can turn it into a duration like “15h30m42s”
# which Docker’s `--filter until=` will accept.
#
# Steps:
#   1. Get the current UNIX epoch in seconds (NOW).
#   2. Get the UNIX epoch for “today at 00:00:00” in seconds (MID).
#   3. DELTA = NOW – MID  → number of seconds since midnight.
#   4. Convert DELTA into H, M, S and format as “<H>h<M>m<S>s”.
# -------------------------------------------------------------

# 1) Get “now” in seconds (POSIX epoch).  Works on both GNU/Linux and macOS: date +%s
NOW_EPOCH=$(date +%s)

# 2) Compute “midnight today” in seconds.
#    - On GNU/Linux (GNU date), we can do: date -d "2025-06-04 00:00:00" +%s
#    - On BSD/macOS (date -j -f), we do: date -j -f "%Y-%m-%d %H:%M:%S" "2025-06-04 00:00:00" +%s
# First, capture YYYY-MM-DD for “today”:
TODAY=$(date +%Y-%m-%d)

# Try GNU date
if date -d "$TODAY 00:00:00" +%s >/dev/null 2>&1; then
    MID_EPOCH=$(date -d "$TODAY 00:00:00" +%s)
# Else try BSD/macOS date
elif date -j -f "%Y-%m-%d %H:%M:%S" "$TODAY 00:00:00" +%s >/dev/null 2>&1; then
    MID_EPOCH=$(date -j -f "%Y-%m-%d %H:%M:%S" "$TODAY 00:00:00" +%s)
else
    echo "Error: Unable to compute midnight of today (unsupported date command)." >&2
    exit 1
fi

# 3) Delta in seconds since midnight
DELTA_SEC=$(( NOW_EPOCH - MID_EPOCH ))

if [ "$DELTA_SEC" -lt 0 ]; then
    # Should never happen unless system clock is weird
    echo "Warning: current time is before midnight? Aborting." >&2
    exit 1
fi

# 4) Break DELTA_SEC into hours, minutes, seconds
HOURS=$(( DELTA_SEC / 3600 ))
REMAINDER=$(( DELTA_SEC % 3600 ))
MINUTES=$(( REMAINDER / 60 ))
SECONDS=$(( REMAINDER % 60 ))

# Format into something like “15h30m42s” (omit any zero fields if you prefer, but Docker accepts all fields)
DURATION=""
if [ "$HOURS" -gt 0 ]; then
    DURATION+="${HOURS}h"
fi
if [ "$MINUTES" -gt 0 ] || [ "$HOURS" -gt 0 ]; then
    # If HOURS > 0, always include minutes (even if 0). If HOURS = 0, include minutes only if > 0.
    DURATION+="${MINUTES}m"
fi
DURATION+="${SECONDS}s"

# In the rare case it's exactly midnight (DELTA_SEC=0), DURATION="0s"
if [ -z "$DURATION" ]; then
    DURATION="0s"
fi

echo "→ Pruning only resources older than today (i.e. created before 00:00)."
echo "   That corresponds to: --filter until=$DURATION (roughly $HOURS h, $MINUTES m, $SECONDS s ago)."

# -------------------------------------------------------------
# Now run each prune with “--filter until=<DURATION>”
# -------------------------------------------------------------
docker container prune -f --filter "until=$DURATION"
docker image prune -af --filter "until=$DURATION"
docker builder prune -af --filter "until=$DURATION"