Create a data stream across your information systems to query, augment and transform data according to Elixir matching rules.
See the generated documentation for more detailed explanations.
The principle is:
- to make each element hop from node to node in order to be processed using the locally present data.
- that any node at any time can emit new elements in the pipeline stream
- to construct processing units on each node on demand. They can die at any time to free memory or because of an exception: they will be restarted on demand.
- to pull elements by chunk in order to allow long processing time without the need of any back-pressure mechanism.
Let's see a processing pipe example:
- the input is a product stream : stream of
{:product,%{field1: value1, field2: value2}} user@jsonserver1contains a json file "/color.json" containing a COLOR mappinguser@jsonserver2contains a json file "/size.json" containing a SIZE mapping- you want to map product color and size according to these mappings
- you want to add a field "deleted" when the mapped color is red
Adap.Piper.defpipe ColorPipe, [{ColorPipe.Rules,[]}]
defmodule JSONMap do
use Adap.Unit.Simple, ttl: 1_000
def init(mapping), do:
{:ok,File.read!("/#{mapping}.json") |> JSON.decode!}
def node("color"), do: :"user@jsonserver1"
def node("size"), do: :"user@jsonserver2"
end
defmodule ColorPipe.Rules do
use Adap.Piper, for: :product
defrule map_color(%{color: color}=prod,_) do
{JSONMap,"color"},color_map->
%{prod| color: color_map[color]}
end
defrule map_size(%{size: size}=prod,_) do
{JSONMap,"size"},size_map->
%{prod| size: size_map[size]}
end
defrule red_is_deleted(%{color: "red"}=prod,_) do
Dict.put(prod,:deleted,true)
end
end
result = [
{:product,%{gender: "male", category: "ipad"}},
{:product,%{color: "carmine", category: "shirt"}},
{:product,%{color: "periwinkle", size: "xxl"}}
] |> Adap.Stream.new(ColorPipe) |> Enum.to_list
assert result == [
{:product,%{gender: "male", category: "ipad"}},
{:product,%{color: "red", category: "shirt", deleted: true}},
{:product,%{color: "blue", size: "large"}}
]