Firebird/Concepts

Firebird

Overview

pipeline

• A Pipe is a data processing unit, it may have zero or more input ports, and may have zero or more output ports
• A Generator is a Pipe that does not have any input ports
• A Sink is a Pipe that does not have any output ports

wiring

You can connect an output port to one ore more input port to set the data flow direction.

Models

Node

Represent a node in the pipeline. A node can have bunch of input ports and bunch of output ports. Each port has a unique id within the node.

Properties

id:              The id of the node, it is unique within a pipeline
title:           A human readable name of this node
description:     Detailed description of this node
pipeline:        The pipeline this node belongs to
input_port_ids:  tuple of all input port ids
output_port_ids: tuple of all output port ids
input:           The default input port
output:          The default output port

method: get_port

def get_port(self, id:str) -> Optional["Port"]
# each port has a unique id within the node.
# return a port given port id

# You can also use [] to get port by name
node["foo"]  # same as node.get_port("foo")

method: on_message

on_message(self, port_name:str, data:Any)

Called when this node receives data. port_name is the name of the port which receive the data, data is the JSON payload of the data.

method: >> and <<

# You can use >>, << to connect nodes, here are examples:
nodeA >> nodeB               # connect default output port of nodeA to default input port of node B
nodeA["foo"] >> nodeB        # connect port "foo" of nodeA to default input port of node B
nodeA["foo"] >> nodeB["bar"] # connect port "foo" of nodeA to port "bar" of node B

# You can also use << as a reverse of >>

method: emit

def emit(self, data:Any, port_id:str=DEFAULT_OUTPUT_PORT_ID)

# emit data to it's output port specified by port_id

Generator

Represent a node that does not have input ports, it is derived from Node.

methods: pump

def pump(self)

# derived class must override this method to pump data to the pipeline.

Sink

Represent a node that does not have output ports, it is derived from Node.

Port

Port

Represent an input port or output port of a node.

Properties

* type:  Either PortType.INPUT or PortType.OUTPUT, represent it is a input port or output port
* id:    ID of the port, it is unique within the node
* owner: The node which this port belongs to

method: >> and <<

# connect this port to other port
# see Node document.

def emit(self, json_data:Any)

# emit JSON data to this port

Pipeline

Represent a pipeline, which has

• bunch of nodes
• A node's output port can connect to another node's input port

Properties:

• mq: message queue
• node_dict: dictionary, key is node name, value is node

Methods:

def message_loop(self):

# enters a message loop, allow each node to process data

def add_node(self, name:str, node_class, *argc, **kwargs)

# add a node to the pipeline, *argc, and **kwargs will be passed to the constructor

def connect(self, *, src_node_name, src_port_name=DEFAULT_PORT_NAME, dst_node_name, dst_port_name=DEFAULT_PORT_NAME)

# connect one node's output port to another node's input port

RabbitMQ