Zentra API

The zentra library provides python bindings to the Zentra Cloud RESTful API. Read the docs here.

What is Zentra Cloud?

Zentra Cloud is a service of the METER Group for delivering data collected by METER data-loggers. The service allows logger owners to invite users to view and download their data. Zentra Cloud provides a graphical user interface as well as a RESTful application programming interface (API). Authenticated users can access data through either interface.

Installation

The zentra library is not yet available on PyPI. Until then, install directly from Github using pip:

pip install git+https://github.com/mt-climate-office/Zentra-API

Usage

The zentra library is designed to conform as closely as possible to the Zentra Cloud REST API, while returning data in useful pandas data structures. For security reasons, zentra enforces the use of personal access tokens as opposed to station-level passwords. It assumes that a user already has an account and password set up with Zentra Cloud. Please refer to the Zentra Cloud API documentation for API call and parameter details.

The zentra library defines four primary classes:

• ZentraToken holds methods and data relating to authentication into the Zentra Cloud API.
• ZentraSettings holds methods and data relating to logger settings.
• ZentraStatus holds methods and data relating to logger status.
• ZentraReadings holds methods and data relating to logger readings.

Each class has methods to build an API request, send a request and parse it, get the data (which wraps the build and parse steps), and an initialization method that if passed adequate information also builds the request, requests the data, and parses it. Methods for ZentraSettings, ZentraStatus, and ZentraReadings classes all require a parsed ZentraToken object in order to request data from the Zentra Cloud.

Loading the library

After installation, load the zentra library with a standard import call to the api module:

import zentra.api

ZentraToken

The ZentraToken class holds methods and data relating to authentication into the Zentra Cloud API. The classes initialization, build, and get methods accept two parameters:

• username: your Zentra Cloud username
• password: your Zentra Cloud password

Create a ZentraToken by initializing with a username and password:

token = ZentraToken(username="[USERNAME]",
                    password="[PASSWORD]")

# access the token by calling the 'token' attribute
token.token

You are strongly encouraged not to hard-code your credentials into a python script, or to enter them in the terminal. One way to avoid this is to save them as environment variables, and call them using the

from os import getenv

token = ZentraToken(username=getenv("zentra_un"),
                    password=getenv("zentra_pw"))

token.token

Alternatively, you can build then parse the token:

from os import getenv

token = ZentraToken().build(username=getenv("zentra_un"),
                            password=getenv("zentra_pw")).parse()

token.token

Or, if you already have a valid token stored locally, you can create a ZentraToken object without a username or password:

from os import getenv

token = ZentraToken(token=getenv("zentra_token"))

token.token

ZentraSettings, ZentraStatus, ZentraReadings

The ZentraSettings, ZentraStatus, ZentraReadings each require authentication with a ZentraToken, and all return information about or from a particular METER device given that device's unique serial number. Like ZentraToken, the classes each have build, parse, and get methods. Parameters include:

• token (required): a parsed ZentraToken object
• sn (required): the serial number for the device
• start_time (optional): Return data with timestamps ≥ start_time. Specify start_time in UTC seconds.
• end_time (optional; ZentraSettings and ZentraStatus only): Return data with timestamps <= end_time. Specify end_time in UTC seconds.
• start_mrid (optional; ZentraReadings only): Return readings with mrid ≥ start_mrid.

The ZentraReadings records are stored as a list of objects of class ZentraTimeseriesRecord, which stores data on the sensors that reported and their records.

After defining a valid ZentraToken, retrieve settings, status, and readings data like this, for example:

from zentra.api import *
from os import getenv

token = ZentraToken(username=getenv("zentra_un"),
                    password=getenv("zentra_pw"))

# Get the settings for a device
settings = ZentraSettings(sn="06-00187",
                          token=token)
# Report the measurement settings
settings.measurement_settings

# Get the status messages for a device
status = ZentraStatus(sn="06-00187",
                      token=token)
# Report the cellular statuses
status.cellular_statuses

# Get the readings for a device
readings = ZentraReadings(sn="06-00761",
                          token=token,
                          start_time=int(datetime.datetime(year=2019,
                                                           month=7,
                                                           day=4).timestamp()))
# Report the readings from the first ZentraTimeseriesRecord
readings.timeseries[0].values

Development

This project has been set up using PyScaffold 3.1. For details and usage information on PyScaffold see https://pyscaffold.org/.

First, clone this project and change into the project directory:

git clone https://github.com/mt-climate-office/Zentra-API
cd Zentra-API

Then, to install the library and its dependencies into your current python environment, run:

python setup.py develop

Testing

This project uses pytest for testing and coverage analysis. To test, from the project directory run:

python setup.py test

Documentation

This project uses pdoc to auto-generate documentation from docstrings in the code. Documentation was generated using this command in the terminal:

pdoc --html --html-dir docs --overwrite ./src/zentra/api.py
mv -i docs/api.m.html docs/index.html