#!/usr/bin/python

# Copyright (C) 2017 ScyllaDB
#
# This file is part of Scylla.
#
# Scylla is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# Scylla is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with Scylla.  If not, see <http://www.gnu.org/licenses/>.

import os
import re
from string import atoi
import scylla_util
import subprocess
import argparse
import yaml
import logging
import sys

if __name__ == "__main__":
    parser = argparse.ArgumentParser(description='IO Setup script for Scylla.')
    parser.add_argument('--ami', dest='ami', action='store_true',
                        help='configure AWS AMI')
    args = parser.parse_args()

    cpudata = scylla_util.scylla_cpuinfo()
    if not scylla_util.is_developer_mode():
        if args.ami:
            idata = scylla_util.aws_instance()
            nr_io_queues = cpudata.nr_shards()

            if idata.instance_class() == "i3":
                sysfs_file = "/sys/block/%s/queue/nr_requests"
                max_seastar_shard_req = 128
                max_sysfs_shard_req = sum([ atoi(file(sysfs_file % x).readline().strip()) for x in idata.ephemeral_disks() ])
                # obtained running iotune multiple times against a single i3 disk.
                max_iotune_disk = 192 * len(idata.ephemeral_disks())
                nr_reqs = min(max_seastar_shard_req * cpudata.nr_shards(), max_sysfs_shard_req, max_iotune_disk)
            elif idata.instance_class() == "i2":
                nr_reqs = 32 * len(idata.ephemeral_disks())
            else:
                nr_reqs = 16 * max(len(idata.ephemeral_disks()), 2)
            if nr_reqs/nr_io_queues < 4:
                nr_io_queues = nr_reqs / 4
            ioconf = file("/etc/scylla.d/io.conf", "w")
            ioconf.write("SEASTAR_IO=\"--num-io-queues {} --max-io-requests {}\"\n".format(nr_io_queues, nr_reqs))
        else:
            if os.environ.has_key("SCYLLA_CONF"):
                conf_dir = os.environ["SCYLLA_CONF"]
            else:
                conf_dir = "/etc/scylla"
            cfg = yaml.load(open(os.path.join(conf_dir, "scylla.yaml")))
            data_dirs = cfg["data_file_directories"]
            if len(data_dirs) > 1:
                logging.warn("%d data directories found. scylla_io_setup currently lacks support for it, and only %s will be evaluated",
                             len(data_dirs), data_dirs[0])

            data_dir = data_dirs[0]
            iotune_args = []
            if cpudata.cpuset():
                iotune_args += [ "--cpuset", ",".join(map(str, cpudata.cpuset())) ]
            elif cpudata.smp():
                iotune_args += [ "--smp", cpudata.smp() ]

            try:
                subprocess.check_call(["iotune",
                                       "--evaluation-directory", data_dir,
                                       "--format", "envfile",
                                       "--options-file", "/etc/scylla.d/io.conf"] + iotune_args)
            except Exception:
                logging.error("%s did not pass validation tests, it may not be on XFS and/or has limited disk space.\n"
                              "This is a non-supported setup, and performance is expected to be very bad.\n"
                              "For better performance, placing your data on XFS-formatted directories is required.\n"
                              "To override this error, enable developer mode as follow:\n"
                              "sudo /usr/lib/scylla/scylla_dev_mode_setup --developer-mode 1", data_dir)
                sys.exit(1)