Decrements value for key.

See inc/3.

Returns property with given key or default.

Increments value with given key.

By default, returns without waiting for the actual increment.

Raises an ArithmeticError if current value associated with key is not a number.

Options

• step: number, 1 — increment step;

• initial: number, 0 — initial value;

• initial: false — to raise KeyError on server if value does not exist;

• cast: false — to return only after the increment;

• !: priority, :avg;

• :timeout, 5000.

Examples

iex> am = AgentMap.new(a: 1.5)
iex> am
...> |> inc(:a, step: 1.5)
...> |> inc(:b, step: 1.5)
...> |> get(:a)
3.0
iex> get(am, :b)
1.5

iex> AgentMap.new()
...> |> sleep(:a, 20)
...> |> put(:a, 1)               # 1
...> |> cast(:a, fn 2 -> 3 end)  # : ↱ 3
...> |> inc(:a, !: :max)         # ↳ 2 :
...> |> get(:a)                  #     ↳ 4
3

Reads metadata information stored under key.

Functions meta/2, upd_meta/4 and put_meta/3 can be used inside callbacks.

Special keys

• :size — current size (fast, but in some rare cases inaccurate upwards);

• :real_size — current size (slower, but always accurate);

• :max_concurrency — a limit for the number of processes allowed to spawn;

• :processes — total number of processes being used (+1 for server itself).

Examples

iex> am = AgentMap.new()
iex> meta(am, :processes)
1
iex> meta(am, :max_concurrency)
5000
iex> am
...> |> sleep(:a, 10)
...> |> sleep(:b, 100)
...> |> meta(:processes)
3
#
iex> sleep(50)
iex> meta(am, :processes)
2
#
iex> sleep(200)
iex> meta(am, :processes)
1

#

iex> am = AgentMap.new()
iex> meta(am, :size)
0
iex> am
...> |> sleep(:a, 10)
...> |> sleep(:b, 50)
...> |> put(:b, 42)
...>
iex> meta(am, :size)       # size calculation is inaccurate, but fast
2
iex> meta(am, :real_size)  # that's better
0
iex> sleep(50)
iex> meta(am, :size)       # worker for :a just died
1
iex> meta(am, :real_size)
0
iex> sleep(40)             # worker for :b just died
iex> meta(am, :size)
1
iex> meta(am, :real_size)
1

#

iex> {:ok, am} =
...>   AgentMap.start_link([key: 1], meta: [custom_key: "custom_value"])
...>
iex> meta(am, :custom_key)
"custom_value"
iex> meta(am, :unknown_key)
nil

Stores metadata information under key.

See meta/2, upd_meta/4.

Examples

iex> am = AgentMap.new()
iex> am
...> |> put_meta(:key, 42)
...> |> meta(:key)
42

iex> am = AgentMap.new()
iex> meta(am, :bar)
nil
iex> meta(am, :bar, :baz)
:baz
iex> meta(am, :max_concurrency)
5000

Functions meta/2, upd_meta/3, put_meta/4 can be used inside callbacks:

iex> am = AgentMap.new()
iex> am
...> |> get(:a, fn _ -> put_meta(am, :foo, :bar) end)
...> |> get(:b, fn _ -> meta(am, :foo) end)
:bar

Suspends the queue for key for t ms.

Returns without waiting for the actual suspend to happen.

Options

• cast: false — to return after the actual sleep;

• !: priority, {:max, +2} — to postpone sleep until calls with a higher priority are executed.

Updates metadata information stored under key.

Underneath, GenServer.cast/2 is used.

See meta/2, put_meta/4.

Options

• cast: false — to wait for the actual update to occur.

Examples

iex> AgentMap.new()
...> |> put_meta(:key, 42)
...> |> upd_meta(:key, fn 42 -> 24 end)
...> |> meta(:key)
24