Class: Jason::LuaGenerator

Inherits:
Object
  • Object
show all
Defined in:
lib/jason/lua_generator.rb

Instance Method Summary collapse

Instance Method Details

#cache_json(model_name, id, payload) ⇒ Object

TODO load these scripts and evalsha



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# File 'lib/jason/lua_generator.rb', line 3

def cache_json(model_name, id, payload)
  expiry = 7*24*60*60 + rand(6*60*60)

  # ensure the content expires first
  cmd = <<~LUA
    local gidx = redis.call('INCR', 'jason:gidx')
    redis.call( 'setex', 'jason:cache:' .. ARGV[1] .. ':' .. ARGV[2] .. ':gidx', #{expiry}, gidx )
    redis.call( 'setex', 'jason:cache:' .. ARGV[1] .. ':' .. ARGV[2], #{expiry - 60}, ARGV[3] )
    return gidx
  LUA

  result = $redis_jason.eval cmd, [], [model_name, id, payload.to_json]
end

#get_payload(model_name, sub_id) ⇒ Object 



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# File 'lib/jason/lua_generator.rb', line 17

def get_payload(model_name, sub_id)
  # If value has changed, return old value and new idx. Otherwise do nothing.
  cmd = <<~LUA
    local t = {}
    local insts = {}
    local miss_ids = {}
    local ids = redis.call('smembers', 'jason:subscriptions:' .. ARGV[2] .. ':ids:' .. ARGV[1])

    for k,id in pairs(ids) do
      local result = redis.call( 'get', 'jason:cache:' .. ARGV[1] .. ':' .. id)
      if (result == false) then
        miss_ids[#miss_ids+1] = id
      else
        insts[#insts+1] = result
      end
    end

    if next(miss_ids) == nil then
      t[#t+1] = insts
      t[#t+1] = redis.call( 'get', 'jason:subscription:' .. ARGV[2] .. ':' .. ARGV[1] .. ':idx' )
    else
      t[#t+1] = miss_ids
      t[#t+1] = 'missing'
    end

    return t
  LUA

  $redis_jason.eval cmd, [], [model_name, sub_id]
end

#get_subscription(model_name, id, sub_id, gidx) ⇒ Object 



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# File 'lib/jason/lua_generator.rb', line 48

def get_subscription(model_name, id, sub_id, gidx)
  # If value has changed, return old value and new idx. Otherwise do nothing.
  cmd = <<~LUA
    local last_gidx = redis.call('get', 'jason:cache:' .. ARGV[1] .. ':' .. ARGV[2] .. ':gidx') or 0

    if (ARGV[4] >= last_gidx) then
      local sub_idx = redis.call( 'incr', 'jason:subscription:' .. ARGV[3] .. ':' .. ARGV[1] .. ':idx' )
      return sub_idx
    else
      return false
    end
  LUA

  $redis_jason.eval cmd, [], [model_name, id, sub_id, gidx]
end

#update_set_with_diff(key, add_members, remove_members) ⇒ Object 



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# File 'lib/jason/lua_generator.rb', line 64

def update_set_with_diff(key, add_members, remove_members)
  cmd = <<~LUA
    local old_members = redis.call('smembers', KEYS[1])
    local add_size = ARGV[1]

    for k, m in pairs({unpack(ARGV, 2, add_size + 1)}) do
      redis.call('sadd', KEYS[1], m)
    end

    for k, m in pairs({unpack(ARGV, add_size + 2, #ARGV)}) do
      redis.call('srem', KEYS[1], m)
    end

    return old_members
  LUA

  args = [add_members.size, add_members, remove_members].flatten

  old_members = $redis_jason.eval cmd, [key], args
  return [old_members, (old_members + add_members - remove_members).uniq]
end