#!/bin/sh
# Starts the bundled Redis unless an external one is named, then the command.
#
# Redis holds the last value of every message, node state and the work queue,
# so without it a restart forgets all three. In the background on purpose: its
# appendonly file is written on every change, so the SIGKILL it gets when the
# container stops loses nothing that was acknowledged.
#
# Its memory-overcommit warning is dropped: the setting is the host kernel's,
# nothing in a container can change it, and it only matters to a fork for a
# snapshot under memory pressure. Every other warning still reaches the log.
set -e

if [ -z "$REDIS_HOST" ]; then
  mkdir -p /data/redis
  redis-server --bind 127.0.0.1 --port 6379 --dir /data/redis \
    --appendonly yes --loglevel warning \
    | grep --line-buffered -v "Memory overcommit must be enabled" &
  i=0
  until redis-cli -h 127.0.0.1 ping >/dev/null 2>&1; do
    i=$((i + 1))
    [ "$i" -lt 100 ] || { echo "bundled redis did not start" >&2; exit 1; }
    sleep 0.1
  done
  export REDIS_HOST=127.0.0.1
fi

exec "$@"