websocket

README

WebSocket plugin for SensorBee

The WebSocket plugin for SensorBee allows to receive data from remote SensorBee instances.

SensorBee will probably support remote query in the future, but it isn't provided at the moment. This plugin helps to build distributed SensorBee topologies until the feature gets ready.

websocket Source

Required parameters

topology

topology is the name of the topology which have the target stream.

stream

stream is the name of the stream to issue queries.

Optional parameters

host

host is the name of the host which runs the target SensorBee. The default value is localhost.

port

port is the port number of the target SensorBee. The default value is 15601.

buffer_size

buffer_size is the integervalue passed to the BUFFER SIZE clause in BQL. The default value is 1024.

drop_mode

drop_mode specifies the value to control the behavior of the buffer when it's full. It has following three values:

• "wait": WAIT IF FULL will be specified in BQL
• "newest": DROP NEWEST IF FULL
• "oldest": DROP OLDEST IF FULL

These values are case-sensitive. The default value is "wait".

Example

CREATE SOURCE remote TYPE websocket WITH
  topology = "my_topology",
  stream = "my_stream",
  host = "anotherhost",
  port = 15601,
  buffer_size = 1024,
  drop_mode = "wait";

This source issues a query equivalent to the following command:

$ bql --uri http://anotherhost:15601/ -t my_topology
my_topology> SELECT RSTREAM * FROM my_stream [RANGE 1 TUPLES, BUFFER SIZE 1024, WAIT IF FULL];

Registering plugin

Add gopkg.in/sensorbee/websocket.v1/plugin to build.yaml of the build_sensorbee command.

plugins:
  - gopkg.in/sensorbee/websocket.v1/plugin

Documentation

Index

• func NewSource(ctx *core.Context, ioParams *bql.IOParams, params data.Map) (core.Source, error)

Functions

func NewSource

func NewSource(ctx *core.Context, ioParams *bql.IOParams, params data.Map) (core.Source, error)

NewSource creates a new WebSocket source to connect to a remote SensorBee instance. The source has following required parameters:

• topology: the name of the topology in the remote instance
• stream: the name of the stream to issue a query

It also has optional parameters:

• host: the name of the host (default: "localhost")
• port: the port number of the remote instance (default: 15601)
• buffer_size: the buffer size in the BUFFER SIZE clause (default: 1024)
• drop_mode: the behavior of the IF FULL clause: "wait", "newest", or "oldest" (default: "wait")