ocf-managed-container/refactored/managed-container.d/applications/postgresql/postgres.sh

# Sourced by managed-container; uses the shared OCF and parameter environment.

pg_command()
{
    local command="$1"

    mc_runtime_exec \
        --user "${PG_OS_USER}" \
        "${CONTAINER_NAME}" \
        sh -c "${command}"
}

pgdata_path()
{
    pg_command '
        if [ -z "$PGDATA" ]; then
            exit 1
        fi

        printf "%s\n" "$PGDATA"
    '
}

pg_running()
{
    pg_command '
        BINDIR="$(pg_config --bindir)" || exit 1
        "$BINDIR/pg_ctl" status -D "$PGDATA" >/dev/null 2>&1
    '
}

pg_ready()
{
    mc_runtime_exec \
        --user "${PG_OS_USER}" \
        "${CONTAINER_NAME}" \
        pg_isready -q \
        -U "${DB_USER}" \
        -d "${DB_NAME}"
}

pg_role()
{
    mc_runtime_exec \
        --user "${PG_OS_USER}" \
        "${CONTAINER_NAME}" \
        psql \
        -U "${DB_USER}" \
        -d "${DB_NAME}" \
        -Atqc 'SELECT pg_is_in_recovery();'
}

pg_wal_receiver_status()
{
    mc_runtime_exec \
        --user "${PG_OS_USER}" \
        "${CONTAINER_NAME}" \
        psql \
        -U "${DB_USER}" \
        -d "${DB_NAME}" \
        -Atqc "SELECT status FROM pg_stat_wal_receiver LIMIT 1;"
}

managed_monitor()
{
    local role

    if ! service_running; then
        ocf_log debug "User service ${SERVICE_NAME} is not active"
        return "${OCF_NOT_RUNNING}"
    fi

    if ! container_running; then
        ocf_log warn \
            "Service ${SERVICE_NAME} is active but container ${CONTAINER_NAME} is not running"
        return "${OCF_NOT_RUNNING}"
    fi

    if ! pg_running; then
        ocf_log debug \
            "Container ${CONTAINER_NAME} is running but PostgreSQL is stopped"
        return "${OCF_NOT_RUNNING}"
    fi

    if ! pg_ready; then
        ocf_exit_reason \
            "PostgreSQL process exists but pg_isready failed"
        return "${OCF_ERR_GENERIC}"
    fi

    role="$(pg_role 2>/dev/null)" || {
        ocf_exit_reason \
            "PostgreSQL is accepting connections but role query failed"
        return "${OCF_ERR_GENERIC}"
    }

    case "${role}" in
        f)
            ocf_log debug \
                "PostgreSQL healthy: role=primary (promoted)"
            return "${OCF_RUNNING_PROMOTED}"
            ;;
        t)
            ocf_log debug \
                "PostgreSQL healthy: role=standby (unpromoted)"
            return "${OCF_SUCCESS}"
            ;;
        *)
            ocf_exit_reason \
                "Unexpected pg_is_in_recovery() result: '${role}'"
            return "${OCF_ERR_GENERIC}"
            ;;
    esac

}

managed_start()
{
    local i monitor_rc

    managed_monitor
    monitor_rc=$?

    case "${monitor_rc}" in
        "${OCF_SUCCESS}")
            ocf_log info \
                "PostgreSQL resource already running unpromoted"
            return "${OCF_SUCCESS}"
            ;;

        "${OCF_RUNNING_PROMOTED}")
            ocf_exit_reason \
                "Refusing start: PostgreSQL is already primary; promotion must occur through promote()"
            return "${OCF_ERR_GENERIC}"
            ;;

        "${OCF_NOT_RUNNING}")
            # Expected for a stopped resource. Continue.
            ;;

        *)
            ocf_exit_reason \
                "Cannot start unhealthy PostgreSQL instance (monitor rc=${monitor_rc})"
            return "${monitor_rc}"
            ;;
    esac

    ocf_log info \
        "Ensuring container service ${SERVICE_NAME} is running"

    if ! service_running; then
        if ! mc_lifecycle_start "${SERVICE_NAME}"
        then
            ocf_exit_reason \
                "Failed to start ${SERVICE_NAME}"
            return "${OCF_ERR_GENERIC}"
        fi
    fi

    for i in $(seq 1 20); do
        container_running && break
        sleep 0.5
    done

    if ! container_running; then
        ocf_exit_reason \
            "Container ${CONTAINER_NAME} did not become running"
        return "${OCF_ERR_GENERIC}"
    fi

    if ! pg_running; then
        #
        # OCF promotable-resource rule:
        # start() must produce an Unpromoted instance.
        #
        # A PostgreSQL data directory without standby.signal would start
        # writable/primary, so never start it from this action.
        #
        if ! pg_command '
            test -f "$PGDATA/standby.signal"
        '
        then
            ocf_exit_reason \
                "Refusing start: PGDATA is not configured as a standby (standby.signal missing)"
            return "${OCF_ERR_GENERIC}"
        fi

        ocf_log info \
            "Starting PostgreSQL as an unpromoted standby inside ${CONTAINER_NAME}"

        if ! pg_command '
            BINDIR="$(pg_config --bindir)" || exit 1
            exec "$BINDIR/pg_ctl" \
                -D "$PGDATA" \
                -l "$PGDATA/postgresql.log" \
                start -w
        '
        then
            ocf_exit_reason "pg_ctl start failed"
            return "${OCF_ERR_GENERIC}"
        fi
    fi

    managed_monitor
    monitor_rc=$?

    case "${monitor_rc}" in
        "${OCF_SUCCESS}")
            ocf_log info \
                "PostgreSQL start completed in unpromoted state"
            return "${OCF_SUCCESS}"
            ;;

        "${OCF_RUNNING_PROMOTED}")
            ocf_exit_reason \
                "PostgreSQL became primary during start; stopping it to preserve OCF role semantics"

            pg_command '
                BINDIR="$(pg_config --bindir)" || exit 1
                exec "$BINDIR/pg_ctl" \
                    -D "$PGDATA" \
                    stop -m fast -w
            ' >/dev/null 2>&1 || true

            return "${OCF_ERR_GENERIC}"
            ;;

        *)
            return "${monitor_rc}"
            ;;
    esac
}

managed_stop()
{
    local i

    if container_running && pg_running; then
        ocf_log info \
            "Stopping PostgreSQL cleanly inside ${CONTAINER_NAME}"

        if ! pg_command '
            BINDIR="$(pg_config --bindir)" || exit 1
            exec "$BINDIR/pg_ctl" \
                -D "$PGDATA" \
                stop -m fast -w
        '
        then
            ocf_exit_reason "pg_ctl stop failed"
            return "${OCF_ERR_GENERIC}"
        fi
    fi

    if service_running; then
        ocf_log info \
            "Stopping container service ${SERVICE_NAME}"

        if ! mc_lifecycle_stop "${SERVICE_NAME}"
        then
            ocf_exit_reason \
                "Failed to stop ${SERVICE_NAME}"
            return "${OCF_ERR_GENERIC}"
        fi
    fi

    for i in $(seq 1 20); do
        if ! service_running && ! container_running; then
            return "${OCF_SUCCESS}"
        fi
        sleep 0.5
    done

    if service_running; then
        ocf_exit_reason \
            "${SERVICE_NAME} remained active after stop"
        return "${OCF_ERR_GENERIC}"
    fi

    if container_running; then
        ocf_exit_reason \
            "${CONTAINER_NAME} remained running after stop"
        return "${OCF_ERR_GENERIC}"
    fi

    return "${OCF_SUCCESS}"
}

# Conservative scoring eligibility only; this does not replace role detection,
# fencing, the promotion action, or the existing controlled-demote WAL checks.
# This strict predicate remains unchanged; disconnected policy is separate below.
mc_pg_promotion_eligible()
{
    local eligible

    eligible="$(
        mc_runtime_exec_bounded 3s --user "${PG_OS_USER}" \
            --env 'PGOPTIONS=-c statement_timeout=2000' \
            "${CONTAINER_NAME}" \
            psql -X -v ON_ERROR_STOP=1 -U "${DB_USER}" -d "${DB_NAME}" -Atqc "
                SELECT CASE WHEN pg_is_in_recovery() THEN
                    NOT pg_is_wal_replay_paused()
                    AND EXISTS (
                        SELECT 1 FROM pg_stat_wal_receiver
                        WHERE status = 'streaming'
                          AND flushed_lsn IS NOT NULL
                          AND pg_last_wal_replay_lsn() >= flushed_lsn
                    )
                ELSE false END;
            " 2>/dev/null
    )" || return 1
    [ "${eligible}" = t ]
}

# One observation supplies both strict connected eligibility and disconnected
# evidence. PostgreSQL restart time deliberately invalidates prior observations,
# including a new basebackup sharing the same PostgreSQL system identifier.
mc_pg_standby_observation()
{
    mc_runtime_exec_bounded 3s --user "${PG_OS_USER}" \
        --env 'PGOPTIONS=-c statement_timeout=2000' \
        "${CONTAINER_NAME}" \
        psql -X -v ON_ERROR_STOP=1 -U "${DB_USER}" -d "${DB_NAME}" -Atqc "
            WITH s AS MATERIALIZED (
                SELECT pg_is_in_recovery() AS recovery,
                       pg_last_wal_replay_lsn() AS replay,
                       r.status AS receiver, r.flushed_lsn AS flush
                FROM (SELECT 1) AS singleton
                LEFT JOIN pg_stat_wal_receiver r ON true
            )
            SELECT json_build_object(
                'identity', json_build_array(
                    (SELECT system_identifier::text FROM pg_control_system()),
                    current_setting('data_directory'),
                    extract(epoch FROM pg_postmaster_start_time())::text),
                'recovery', recovery,
                'paused', CASE WHEN recovery THEN pg_is_wal_replay_paused() ELSE true END,
                'receiver', receiver, 'replay', replay::text, 'flush', flush::text,
                'strict', CASE WHEN recovery THEN
                    NOT pg_is_wal_replay_paused() AND receiver = 'streaming'
                    AND flush IS NOT NULL AND replay >= flush
                    ELSE false END)
            FROM s;
        " 2>/dev/null
}

mc_pg_standby_score()
{
    local observation
    observation="$(mc_pg_standby_observation)" || return 1
    # The helper is root-owned alongside the modules; state never enters the
    # rootless container. A failed/slow helper always withdraws eligibility.
    printf '%s' "${observation}" | timeout --kill-after=1s 1s python3 \
        "${MC_APPLICATION_DIR}/promotion_state.py" \
        "${MC_PROMOTION_RESOURCE_INSTANCE:-}" \
        "${SERVICE_USER}" "${SERVICE_NAME}" "${CONTAINER_NAME}" \
        "${OCF_RESKEY_disconnected_max_age:-300}"
}