#!/usr/bin/env python3
# -*- coding: utf-8 -*-
# Copyright 2017, Florent Thiery
'''
Criticality: Normal
Checks that partitions are in conformity with expected norms, and that sufficient free space is available
'''
import subprocess
import sys
import os

BS = 512


def to_gbytes(size_bytes):
    return int(round(size_bytes / (1024 * 1024 * 1024)))


def read_file(fname):
    with open(fname, 'r') as f:
        return f.read()

paths = [
    {
        'mount_point': '/',
        'recommended_types': ('ext4',),
        'min_size_gbytes': 14,
        'min_free_size_gbytes': 5,
    },
    {
        'mount_point': '/home/msuser/msinstance',
        'recommended_types': ('ext4', 'nfsv4'),
        'min_size_gbytes': 400,
        'min_free_size_gbytes': 10,
    },
    {
        'type': 'swap',
        'min_size_gbytes': 1,
    },
]


def get_swap_gbytes():
    d = read_file('/proc/meminfo')
    for l in d.split('\n'):
        if 'SwapTotal'in l:
            swap = l.split('SwapTotal:')[1].strip()
            swap_kbytes, unit = swap.split(' ')
            if unit != 'kB':
                print('Warning, unexpected unit %s' % unit)
            swap_gbytes = int(round(int(swap_kbytes) / (1024 * 1024)))
            return swap_gbytes


def get_path(path):
    # Filesystem     Type   1B-blocks        Used   Available Use% Mounted on
    # /dev/loop2     ext4 52710469632 38253940736 11755397120  77% /
    status, output = subprocess.getstatusoutput('df --output="source,fstype,size,used" -B 1 %s | tail -n 1' % path)
    if status == 0:
        dev, fstype, size, used = output.split()
    else:
        dev = fstype = size = used = None
    return dev, fstype, to_gbytes(int(size)), to_gbytes(int(used))


def check_allocation(dev):
    root_dev = os.path.basename(dev)[:3]
    d = read_file('/proc/partitions')
    dev_partitions = list()
    for l in d.split('\n'):
        if root_dev in l:
            dev_partitions.append(l)

    max_size = 0
    total_size = 0
    for p in dev_partitions:
        major, minor, blocks, name = p.split()
        size = int(blocks) * 512
        if name == root_dev:
            max_size = size
        else:
            total_size += size
    unallocated = max_size - total_size
    unallocated_gbytes = to_gbytes(unallocated)
    if unallocated_gbytes > 1:
        print('Warning, %s GB are unallocated on %s' % (unallocated_gbytes, root_dev))
        return False
    return True

error = False
warning = False


def check_path(p):
    global error
    global warning

    psize = None
    mount_point = p.get('mount_point')
    if mount_point:
        if os.path.isdir(mount_point):
            name = mount_point
            dev, fstype, psize, used = get_path(p['mount_point'])
            if fstype not in p.get('recommended_types'):
                print('Warning, fs type %s not recommended (recommended: %s)' % (fstype, p['recommended_types']))
                warning = True
            if 'nfs' not in dev:
                warning = not check_allocation(dev)
            free_gb = psize - used
            min_free_size_gbytes = p.get('min_free_size_gbytes')
            if min_free_size_gbytes and free_gb < min_free_size_gbytes:
                print('%s has less than %s GB free (%s GB free)' % (mount_point, min_free_size_gbytes, free_gb))
                error = True
        else:
            print('%s not found, cannot check' % mount_point)
    elif p.get('type') == 'swap':
        name = 'swap'
        psize = get_swap_gbytes()

    if psize and psize < p['min_size_gbytes']:
        print('%s is smaller than the minimum required size (%s GB < %s GB)' % (name, psize, p['min_size_gbytes']))
        error = True

for p in paths:
    check_path(p)

OK = 0
ERROR = 1
WARNING = 3
UNTESTABLE = 2

if error:
    print('Errors found')
    code = ERROR
elif warning:
    print('Some warnings were found')
    code = WARNING
else:
    print('All ok')
    code = OK

sys.exit(code)