Testing with ease: master-master replication in Tarantool

As an example of the master-wizard of a Tarantool cluster, I propose to make a small text multiplayer game where each participant seeks to score more points.

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---

- bomberman. 80x40. . , . . , .

---

1. Tarantool 2- https://bit.ly/2IL3JSc

   
   
   

2. :

   
   
   

$ git clone https://github.com/filonenko-mikhail/mmgame.git
$ cd mmgame

1. :
   
   
   • , .
     
     

     $ reset && clear
     $ tarantool ./foodmaker.lua 127.0.0.1:3301

2. :
   
   
   • — ;
   • — , ;
   • — .
     
     

     $ reset && clear
     $ tarantool ./player.lua 127.0.0.1:3301 127.0.0.1:3302 ./player1data

3. . :
   
   
   • , ;
   • .
4. 2 :

$ reset
$ tarantool ./player.lua 127.0.0.1:3301 127.0.0.1:3303 ./player2data

1. — .

Troubleshooting

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• ,
  
  
  • reset <Enter>
• ER_REPLICASET_UUID_MISMATCH: Replica set UUID mismatch: expected 4f8d5028-3f4e-4f8f-a237-bb3db620813f, got 03982784-c023-4661-afe1-96752d90df86
  
  
  • , ,
• ER_UNKNOWN_REPLICA: Replica 904c70b2-be5a-4e5f-afd0-daa0be66f729 is not registered with replica set d4f37bc6-3a71-43a2-8ca5-65e2bcc0bfda
  
  
  • ,

, - , https://bit.ly/37l0awn

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---

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---

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Tarantool — , . instance uuid. replicaset uuid.

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• foodmaker () cluster uuid.

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---

Tarantool

Tarantool, , , — .

Tarantool Lua JIT-.

Lua.

Lua-. , – Tarantool Cartridge.

---

box.cfg. .

:

• replication
• replication_connect_quorum
• replication_connect_timeout

, , , . , :

box.cfg{
    listen=server,
    replication_connect_quorum=0,
    replication_connect_timeout=0.1,
    work_dir=wrkdir,
    log="file:foodmaker.log",
}

---

, , .

box.cfg{
    listen=localserver,
    replication={ remoteserver },
    replication_connect_timeout=60,
    replication_connect_quorum=1,
    work_dir=wrkdir,
    log="file:player.log"
}

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:

• add_player.

  
  
  

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  function add_player(server)
  if box.session.peer() == nil then
      return false
  end
  local server = uri.parse(server)
  local replica = uri.parse(box.session.peer())
  replica.service = server.service
  replica.login = conf.user
  replica.password = conf.password
  replica = uri.format(replica, {include_password=true})
  local replication = box.cfg.replication or {}
  local found = false
  for _, it in ipairs(replication) do
      if it == replica then
          found = true
          break
      end
  end
  if not found then
      table.insert(replication, replica)
      box.cfg({replication={}})
      box.cfg({replication=replication})
  end
  return true
  end

  
  
  

• , .

  
  
  

  _G.conn = netbox.connect(remoteserver,
  {wait_connected=false, reconnect_after=2})
  conn:on_connect(function(client)
  fiber.new(function ()
      local rc, res = pcall(client.call, client, 'add_player', {localserver})
      if not rc then
          log.info(res)
      end
  end)
  end)

  
  
  

---

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Data Definition Language

DDL-, :

• .
  
  

  box.schema.space.create(<name>, options)

• .
  
  

  box.space.<name>:format(
  {{name=<field_name>, type=<field_type>},
   ...,
  })

• .
  
  

  box.space.<name>:create_index(<index_name>,
  {
      parts={{field=<field_name> type=<field_type>},
          ...,
      },
      unique=false|true,
  })

• .
  
  

  box.schema.user.create(<name>, {password=<pass>})

• .
  
  

  box.schema.user.grant(<name>, ....)

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  box.schema.func.create(<name>)

---

. , .

while true do
    if type(box.cfg) ~= 'function'
    and box.space[conf.space_name] ~= nil 
    and not box.info.ro then
        break
    end
    fiber.sleep(0.1)
end

---

Tarantool

Tarantool .

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  box.ctl.on_schema_init(<CALLBACK>)

• .
  
  

  box.ctl_on_schema_init(function()
  box.space._space:on_replace(<CALLBACK 2>)
  end)

• .
  
  

  box.ctl.on_schema_init(function()
  box.space._space:on_replace(function(old, space)
      if not old and sp and sp.name == <USER SPACE NAME> then
          box.on_commit(<CALLBACK 3>)
      end
  end)
  end)

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  box.ctl.on_schema_init(function()
  box.space._space:on_replace(function(old, sp)
      if not old and sp and sp.name == <USER SPACE NAME> then
          box.on_commit(function()
              box.space[sp.name]:on_replace(<USER TRIGGER>)
          end)
      end
  end)
  end)

---

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Data Modification Language

-- 
box.space.Name.insert({id, sprite, x, y, type, health})
--    
box.space.Name.put({id, sprite, x, y, type, health})

box.space.Name.update({primary key}, {{operation, field, value}})

box.space.Name.delete({primary key})

---

. ID instance uuid.

.

, tcgetattr tcsetattr LuaJIT FFI.

.

box.begin()

local rc, res, err = pcall(function()
    ... 
    box.space[conf.space_name]:put(bomb)
    box.space[conf.space_name]:update(player['id'], 
        {{'-', conf.health_field, conf.bomb_energy}})
end)
if not rc then
    log.info(res)
    box.rollback()
else
    box.commit()
end

.

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---

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replication_anon.

box.cfg{listen=localserver,
        replication={ remoteserver },
        replication_connect_timeout=60,
        replication_connect_quorum=1,
        read_only=true,
        replication_anon=true,
        work_dir=wrkdir}

---

:

• , «-» Tarantool.
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Tarantool, codesign .

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1. Tarantool .
2. Telegram-.