Adding README

Author: dchandan

README.md

@@ -1,2 +1,101 @@
-# DACCS python client
-A python library to access DACCS network information.
+# Marble python client
+A python library to access information about the Marble climate infomatics network. The library provides a pythonic interface to the Marble network's [central registry](https://github.com/DACCS-Climate/Marble-node-registry). Users of the network are encouraged to use this library to access the network information and avoid hardcoding URLs to various nodes or services.
+
+## Basic usage
+
+The first thing to do is to get a `client` object:
+
+```python
+>>> from marble_client import MarbleClient
+
+>>> client = MarbleClient()
+```
+
+All the information about the network can now be retrieved from the `client` object. E.g. the nodes available in the network can be accessed as:
+```python
+>>> client.nodes
+{'UofT': <marble_client.node.MarbleNode at 0x10c129990>,
+ 'PAVICS': <marble_client.node.MarbleNode at 0x10c6dd690>,
+ 'Hirondelle': <marble_client.node.MarbleNode at 0x10c6dd890>}
+```
+The returned object is a python `dict` with node names for keys and `MarbleNode` objects as values. A particular node can be accessed as:
+
+```python
+>>> mynode = client['UofT']
+>>> type(mynode)
+marble_client.node.MarbleNode
+```
+
+Now that one has a Marble node of interest, a useful operation would be to check if that node is online in realtime, this can be done as:
+
+```python
+>>> mynode.is_online()
+True
+```
+
+The URL for the node can be retrieved as:
+```python
+>>> mynode.url
+'https://daccs.cs.toronto.edu'
+```
+
+Various other qualities about the node can be accessed as shown below (see [implementation](https://github.com/DACCS-Climate/marble_client_python/blob/main/marble_client/node.py) for the full list of available attributes).
+
+```python
+>>> mynode.affiliation
+'University of Toronto'
+>>> mynode.contact
+'[email protected]'
+>>> mynode.marble_version  # The version of the software stack available on this node
+'1.27.0'
+>>> mynode.location
+{'longitude': -79.39, 'latitude': 43.65}
+```
+
+The "services" that a Marble node offers can differ from one node to another. A list of which services are offered at a given node can be inquired as follows:
+```python
+>>> mynode.services
+['geoserver',
+ 'flyingpigeon',
+ 'finch',
+ 'raven',
+ 'hummingbird',
+ 'thredds',
+ 'jupyterhub',
+ 'weaver']
+```
+
+To get further information on one of the services, first retrieve that service. This can be done in one of two ways:
+```python
+>>> service = mynode['thredds']
+>>> type(service)
+marble_client.services.MarbleService
+>>> 
+>>> service = mynode.thredds
+>>> type(service)
+marble_client.services.MarbleService
+```
+
+The most important thing one needs from the service is the endpoint at which the service is located:
+```python
+>>> service.url
+'https://daccs.cs.toronto.edu/thredds/'
+```
+
+The service URL can also be accessed directly using the service object's name:
+```python
+>>> service
+'https://daccs.cs.toronto.edu/thredds/'
+```
+
+Various attributes that can be accessed on the `MarbleService` object can be found by consulting the [implementation](https://github.com/DACCS-Climate/marble_client_python/blob/main/marble_client/services.py).
+
+Of course, all operations can be chained, so if you don't need `MarbleClient`, `MarbleNode` or `MarbleService` objects for future operations, then to get, for example, the weaver service endpoint for the "PAVICS" node, one can do:
+```python
+>>> url = MarbleClient()["PAVICS"].weaver.url # returns a string object
+>>> print(f"Weaver URL is {url}")
+Weaver URL is https://pavics.ouranos.ca/weaver/
+>>> # A MarbleService object is returned that can be used wherever a string can be used
+>>> print(f"Weaver URL is {MarbleClient()['PAVICS'].weaver}")
+Weaver URL is https://pavics.ouranos.ca/weaver/
+```