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Description:

iotrelay 1.2.3

IoT Relay: Giving Voice to Your Things
Release v1.2.3
In greater and greater numbers, “things” are capable of gathering data
about their environment. These things have an interface to retrieve the
measurements being taken but contain no way of pushing this data to the
Internet. For example, home weather stations often contain only a USB
interface and no network capability. Other devices may have network
capability, such as ZigBee®, but still don’t have a direct way to send
data to Internet connected hosts.
Internet of Things Relay is an application and framework for gathering
data from sources and relaying it to destinations. It is somewhat like
publish/subscribe except that it’s geared more toward devices that are
unable to initiate a connection (they must be polled to get at their
data).
IoT Relay provides basic setup and matches data sources with interested
handlers. The rest of the work is left to plugins.

Installation
IoT Relay is available via PyPI.
$ pip install iotrelay
It is also necessary to create an (initially empty) ini-style
file: ~/.iotrelay.cfg.
[itorelay]

Plugins
Before IoT Relay can do anything useful, it needs plugins. There are
plugin types: source and handler. Source plugins generate data. Handler
plugins handle or do something with data that source plugins produce.
These definitions are intended to be open-ended. Although IoT Relay was
developed with the intention of relaying time-series type data between
remote sources and remote destinations, a handler could instead view
each datum as an event and trigger some action. Likewise, data source
plugins do not have to simply pass the data they are collecting. They
may process the data in some way before making it available to
interested handlers.

Data Source Sample Plugin
A data source definition is a class which provides a get_reading()
method and a constructor which accepts a config parameter. The
get_reading() method must return one or more instances of the
Reading() class or None. In this example, create a file called
iotrelay_sample_source.py and enter the following code.
# iotrelay_sample_source.py

import random
from iotrelay import Reading

class DataSource(object):
def __init__(self, config):
self.config = config

def get_readings(self):
return Reading('sample', random.randint(1, 100))
IoT Relay uses setuptools to find plugins registered in the
iotrelay group. Datasources should use the entry-point name
source. In the same directory as iotrelay_sample_source.py,
the following code should be placed in setup.py.
# setup.py

from setuptools import setup

setup(name='iotrelay-sample-source',
install_requires=['iotrelay'],
py_modules=['iotrelay_sample_source'],
entry_points={
'iotrelay': ['source=iotrelay_sample_source:DataSource']
}
)
Install the source plugin by typing:
$ python setup.py install

Data Handler Sample Plugin
Like the previous example, create a new directory with two files:
# iotrelay_sample_handler.py

class Handler(object):
def __init__(self, config):
self.config = config

def set_reading(self, reading):
print(reading)

# setup.py

from setuptools import setup

setup(name='iotrelay-sample-handler',
install_requires=['iotrelay'],
py_modules=['iotrelay_sample_handler'],
entry_points={
'iotrelay': ['handler=iotrelay_sample_handler:Handler']
}
)
Install the handler plugin by typing:
$ python setup.py install

Plugin Configuration
The minimal source plugin used in this example does not require any
configuration. The ‘reading types’ option in a handler’s configuration
specifies which reading types a handler will receive. In order to
receive readings from the ‘iotrelay-sample-source’ plugin, the
‘reading type’ option in the iotrelay-sample-handler would be ‘sample’.
This corresponds to the reading_type attribute set by the Reading
constructor when get_readings() was called.
The section names correspond directly to the plugin names, as defined
in setup.py.
; ~/.iotrelay.cfg

[iotrelay]

[iotrelay-sample-source]
[iotrelay-sample-handler]
reading types = sample
Any options specified in each plugins section will be passed to that
plugin’s constructor during initialization.

Running IoT Relay
Start IoT Relay with the following command:
$ iotrelay

License
IoT Relay is licensed under The BSD 2-Clause License.

License
Copyright © 2017, Emmanuel Levijarvi
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:

Redistributions of source code must retain the above copyright notice, this
list of conditions and the following disclaimer.
Redistributions in binary form must reproduce the above copyright notice,
this list of conditions and the following disclaimer in the documentation
and/or other materials provided with the distribution.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS “AS IS”
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.