#!/bin/sh
# kea-operator initContainer.
#
# Prepares the shared run dir, finalises this pod's kea-dhcp4 config (the HA
# this-server-name is derived from the StatefulSet ordinal, known only at pod
# start), and waits for the HA peer DNS to resolve before the main kea
# containers start. Every input arrives as an environment variable set by the
# operator; nothing is interpolated into this file, so it is shellcheck-clean
# and testable on its own.
set -eu

# StatefulSet pod names are "<sts>-<ordinal>"; the ordinal is this HA peer's id.
ord="${POD_NAME##*-}"

# The run dir is a shared emptyDir. Kea 2.6+ refuses a control socket in a
# world-accessible directory, so tighten it to 0750.
mkdir -p "$RUN_DIR"
chmod 0750 "$RUN_DIR"

# Finalise the per-pod dhcp4 config: substitute this pod's HA peer name into the
# shared (pod-independent) config projected from the ConfigMap.
sed "s/${THIS_SERVER_PLACEHOLDER}/server${ord}/g" \
	"${CONFIG_DIR}/kea-dhcp4.conf" >"$DHCP4_CONF"

# The ctrl-agent config is pod-independent; stage it in the shared run dir so
# the main container can exec kea directly with no wrapper.
cp "${CONFIG_DIR}/kea-ctrl-agent.conf" "$CTRL_AGENT_CONF"

# The HA hook resolves peer URL hostnames once at load; on a cold start the
# StatefulSet peer DNS records may not resolve yet and kea exits hard instead of
# retrying. Wait (bounded) for the config to validate, then fail loud so the
# kubelet restarts this initContainer rather than starting a doomed server.
i=0
until "$DHCP4_BIN" -t "$DHCP4_CONF" >/dev/null 2>&1; do
	i=$((i + 1))
	if [ "$i" -ge "$WAIT_ATTEMPTS" ]; then
		echo "kea-init: config failed to validate after ${WAIT_ATTEMPTS} attempts" >&2
		exit 1
	fi
	sleep "$WAIT_SLEEP"
done