apt-retry

#!/usr/bin/env bash
set -e

# Retry wrapper for apt commands to handle transient mirror failures.
# Uses decorrelated jitter: delay = rand(base, 3 * prev_delay), capped at max_delay
# Usage: apt-retry apt-get update && apt-retry apt-get install -y <packages>

RED='\033[0;31m'
NC='\033[0m' # No Color

max_attempts=5
base_delay=2
max_delay=20

# Decorrelated jitter: random value between base_delay and 3 * previous delay, capped
next_delay() {
    local prev=$1
    local range=$((3 * prev - base_delay + 1))
    local next=$((base_delay + RANDOM % range))
    if [ $next -gt $max_delay ]; then
        next=$max_delay
    fi
    echo $next
}

delay=$base_delay
attempt=1

while [ $attempt -le $max_attempts ]; do
    if "$@"; then
        exit 0
    fi
    if [ $attempt -lt $max_attempts ]; then
        echo -e "${RED}apt command failed (attempt $attempt/$max_attempts), retrying in ${delay}s...${NC}"
        sleep $delay
    fi
    attempt=$((attempt + 1))
    delay=$(next_delay $delay)
done

echo -e "${RED}apt command failed after $max_attempts attempts${NC}"
exit 1