#!/sbin/openrc-run
# rds-agent — Spinifex RDS in-guest agent. Reaches the control plane over
# TLS+SigV4 (never NATS), signing with IMDS instance-role credentials. Static
# config comes from /etc/spinifex-rds/agent.env, which carries no secrets.

description="Spinifex RDS instance agent"
command="/usr/local/bin/rds-agent"
command_background="yes"
pidfile="/run/rds-agent.pid"
output_log="/var/log/rds-agent.log"
error_log="/var/log/rds-agent.log"

start_stop_daemon_args="--wait 2000"

AGENT_ENV="/etc/spinifex-rds/agent.env"
HANDOFF_ENV="${RDS_HANDOFF_DIR:-/run/spinifex-rds}/bootstrap.env"

# The agent retries indefinitely, so this only bounds how long the boot waits
# before letting rds-init fail visibly rather than hanging forever.
handoff_timeout="${RDS_HANDOFF_TIMEOUT:-120}"

depend() {
    need net
    before rds-init
    after localmount
}

start_pre() {
    # An absent file is tolerated, so the agent still starts and logs why it
    # cannot reach the gateway.
    if [ -f "${AGENT_ENV}" ]; then
        # shellcheck disable=SC1090
        . "${AGENT_ENV}"
        export RDS_GATEWAY_URL RDS_GATEWAY_CA RDS_REGION RDS_DB_INSTANCE_IDENTIFIER \
            RDS_ENGINE_VERSION RDS_HANDOFF_DIR RDS_ENGINE_HOST RDS_ENGINE_PORT \
            RDS_PG_ISREADY RDS_POLL_WAIT
    fi
}

start_post() {
    # `before rds-init` only orders the starts; rds-init needs the fetched config
    # itself. The agent writes bootstrap.env last and renames it into place, so
    # its appearance means the whole handoff is there.
    ebegin "Waiting for the RDS bootstrap handoff"
    _waited=0
    while [ ! -f "${HANDOFF_ENV}" ]; do
        if [ "${_waited}" -ge "${handoff_timeout}" ]; then
            eend 1 "no bootstrap handoff after ${handoff_timeout}s; see /var/log/rds-agent.log"
            # The agent keeps retrying, so it is left running: rds-init fails on
            # the missing handoff and the engine stays down, which is what the
            # control plane observes.
            return 0
        fi
        sleep 1
        _waited=$((_waited + 1))
    done
    eend 0
}