Getting free VPS from Oracle Cloud

There is new always-free offer on Oracle site:
– AMD Epyc CPU: 2 servers, each with: 1 core, 1 GB ram, 50 GB HDD, 480 mb/s connection
– Ampere ARM CPU: 4 servers, each with: 1 core 2.8GHz, 6 GB ram, 50 GB HDD, 1gb/s connection
– 10 TB/month transfer limit for all your machines together

These 4 Ampere servers you can combine into 1 server: 4×2.8GHz, 24 GB ram, 50 GB HDD with 4gb/s connection!
You can also create 6 VPSes for 6 small projects.

Registration:
https://www.oracle.com/pl/cloud/free/
You will have to add credit card to account. Virtual/prepaid cards are not accepted. Revolut virtual card generated in smartphone application is not accepted, but physical Revolut card is ok.

It takes around 15 minutes to activate account after you register.

How to order free 4 core VPS and unlock internet access

When you order any dedic or VPS, it always comes with all internet access opened by default. Here we get machine with almost everything closed (except port 22 for SSH). Every port is blocked in Oracle Cloud panel and in Ubuntu.
If you install nginx on it, it will say in webbrowser that site is offline. Read next 16 steps to unlock all ports.

Go to https://cloud.oracle.com/ and login to your account. Click on ‘Create a VM instance’.

Click on ‘Edit Image and shape’.

Click on ‘Change image’.

Select ‘Canonical Ubuntu’ and click ‘Select image’.

Click on ‘Change shape’.
1. Select shape ‘Ampere’
2. Unroll options
3. Change OCPUs number to 4, it will automatically change RAM to 24 GB
4. Tick ‘VM.Standard.A1.Flex’
5. Click ‘Select shape’

For next step machine configuration step, you must have SSH key pair. If you already have one, you can skip next 3 steps.

To generate key pair you need ‘Git Bash’. You can download it here: https://git-scm.com/download/win

Run Git Bash using Windows Search. Just type ‘git’, it should find it.

In Git Bash window type:

ssh-keygen.exe -t rsa

It will generate SSH key pair and save it in your Windows user directory, in subdirectory .ssh. This directory may be hidden (depends on Windows settings), so you can’t easily navigate there. In this case, you can open any directory in Windows explorer, click on address bar, type:

%HOMEPATH%/.ssh

and click Enter. It should open folder with your id_rsa.pub file. You can copy it on desktop or to Downloads folder, to make it easy to find.

On Oracle page scroll to ‘Add SSH Keys’ and select option ‘Upload public key files (.pub)’.

Select file ‘id_rsa.pub’ we generated in previous 3 steps in file picker (button ‘Browse’). Oracle will upload it to your new VPS. Git Bash with automatically login to your server using this key – using all keys which are in .ssh directory – when you use ‘ssh’ command in it.

Your machine should change status to ‘Running’ within 1 minute. On right top side of page, there will appear IP of your server. Copy it. We will use it later.

There will also appear ‘Virtual cloud network’ with some random name. Click on it.

Click on Subnet name – again some random value.

Click on Default Security List name – again some random value.

Click ‘Add Ingress Rules’.

In ‘source CIDR’ type:

0.0.0.0/0

and click ‘Add Ingress Rules’.

Network TCP – like Tibia and www – traffic is unlocked in Oracle Cloud panel. You may also unblock UDP protocol traffic, if you plan to host TeamSpeak or other application which uses UDP.

Now we got to unlock traffic in Ubuntu. Open Git Bash and type:

ssh ubuntu@x.x.x.x

with your server IP in place of x.x.x.x, like ssh ubuntu@138.3.243.101
On first connection it will ask you, if you are sure that you connected to valid server. Type ‘yes’ and press Enter.

You are now connected to your VPS, but you still can’t run web server or OTS on it. Type:

sudo su
iptables -I INPUT -j ACCEPT
iptables-save > /etc/iptables/rules.v4

It will unlock all incoming traffic in Ubuntu.

[OTS] Lists of unique numbers kept in ‘player storage’

Friend asked me about code to keep ‘auto loot lists’ in storage. So player can configure few lists of items and then just switch between them, when he goes to other spawn with different loot.

-- config
local listsStartStorage = 550000000
local maximumListsCount = 10
local maximumElementsPerList = 100

-- variables for calculations
local listOffset = maximumElementsPerList + 1

function lists_getLists(player)
    local result = {}
    for i = 1, maximumListsCount do
        result[i] = lists_getListElementsCount(player, i)
    end

    return result
end

function lists_getListElementsCount(player, listId)
    local startStorage = listsStartStorage + listOffset * listId
    return math.max(0, player:getStorage(startStorage))
end

function lists_getListElements(player, listId)
    local result = {}
    local startStorage = listsStartStorage + listOffset * listId
    local listElementsCount = lists_getListElementsCount(player, listId)
    for i = startStorage + 1, startStorage + listElementsCount do
        table.insert(result, player:getStorage(i))
    end

    return result
end

function lists_removeAllListElements(player, listId)
    local startStorage = listsStartStorage + listOffset * listId
    local listElementsCount = lists_getListElementsCount(player, listId)
    for i = startStorage + 1, startStorage + listElementsCount + 1 do
        player:setStorage(i, -1)
    end
    player:setStorage(startStorage, -1)
end

function lists_getListElement(player, listId, elementKey)
    local elementStorage = listsStartStorage + listOffset * listId + elementKey
    return player:getStorage(elementStorage)
end

local function lists_assertListId(listId)
    assert(listId >= 1, 'minimum list id is 1')
    assert(listId <= maximumListsCount, 'maximum list id is 1' .. maximumListsCount)
end

local function lists_assertElementKey(elementKey)
    assert(elementKey >= 1, 'minimum list element id is 1')
    assert(elementKey <= maximumElementsPerList, 'maximum list element id is ' .. maximumElementsPerList)
end

-- this is for internal use only, should not be used by user
local function lists_setListElement(player, listId, elementKey, elementValue)
    lists_assertListId(listId)
    lists_assertElementKey(elementKey)
    local elementStorage = listsStartStorage + listOffset * listId + elementKey
    player:setStorage(elementStorage, elementValue)
end

-- this is for internal use only, should not be used by user
local function lists_setListElementsCount(player, listId, count)
    lists_assertListId(listId)
    lists_assertElementKey(count)
    local startStorage = listsStartStorage + listOffset * listId
    player:setStorage(startStorage, count)
end

function lists_addListElement(player, listId, elementValue)
    local elements = lists_getListElements(player, listId)
    for k, v in pairs(elements) do
        if v == elementValue then
            return
        end
    end

    local elementsCount = lists_getListElementsCount(player, listId)
    lists_setListElement(player, listId, elementsCount + 1, elementValue)
    lists_setListElementsCount(player, listId, elementsCount + 1)
end

function lists_removeListElement(player, listId, elementValue)
    local elements = lists_getListElements(player, listId)
    local elementToRemovePosition = nil
    for k, v in pairs(elements) do
        if v == elementValue then
            elementToRemovePosition = k
            break
        end
    end

    if elementToRemovePosition then
        local elementsCount = lists_getListElementsCount(player, listId)
        for i = elementToRemovePosition + 1, elementsCount  do
            local nextElementValue = lists_getListElement(player, listId, i)
            lists_setListElement(player, listId, i - 1, nextElementValue)
        end
        lists_setListElement(player, listId, elementsCount, -1)
        lists_setListElementsCount(player, listId, elementsCount - 1)
    end
end

TESTS:

Player = {}
function Player:new()
    o = {storages = {}}
    setmetatable(o, self)
    self.__index = self
    return o
end

function Player.getStorage(self, k)
    if (self.storages[k]) then
        return self.storages[k]
    end
    return -1
end

function Player.setStorage(self, k, v)
    if (v == -1) then
        v = nil
    end
    self.storages[k] = v
end

function Player.dumpStorages(self)
    local storages = 'storages: '
    for k, v in pairs(self.storages) do
        storages = storages .. k .. '=' .. v .. ', '
    end
    print(storages)
end

local function printPlayerListsElementsCount(player)
    local playerLists = lists_getLists(player)
    for k, v in pairs(playerLists) do
        local listElementsString = ''
        for k2, v2 in pairs(lists_getListElements(player, k)) do
            listElementsString = listElementsString .. ' ' .. k2 .. '=' .. v2 .. ', '
        end
        print ('list', k, 'elements', v, 'values', listElementsString)
    end
end

player = Player:new()

print()
player:dumpStorages()
print('start - empty list')
printPlayerListsElementsCount(player)

print()
player:dumpStorages()
lists_addListElement(player, 2, 2001)
lists_addListElement(player, 2, 2002)
print('added 2 elements to list 2')
player:dumpStorages()
printPlayerListsElementsCount(player)

print()
player:dumpStorages()
lists_addListElement(player, 1, 1001)
lists_addListElement(player, 1, 1002)
lists_addListElement(player, 1, 1003)
lists_addListElement(player, 1, 1004)
lists_addListElement(player, 1, 1005)
print('added 5 elements to list 1')
player:dumpStorages()
printPlayerListsElementsCount(player)

print()
player:dumpStorages()
lists_removeListElement(player, 1, 1001)
print('removed first element from list 1')
player:dumpStorages()
printPlayerListsElementsCount(player)

print()
player:dumpStorages()
lists_removeListElement(player, 1, 1005)
print('removed last element from list 1')
player:dumpStorages()
printPlayerListsElementsCount(player)

print()
player:dumpStorages()
lists_removeListElement(player, 1, 1003)
print('removed middle element from list 1')
player:dumpStorages()
printPlayerListsElementsCount(player)

print()
player:dumpStorages()
lists_removeAllListElements(player, 1)
print('removed all elements from list 1')
player:dumpStorages()

You can paste code and tests to online tool like: https://www.tutorialspoint.com/execute_lua_online.php