pybsn

pybsn is a python interface to Big Switch Network products

Installation

pybsn supports Python versions 3.6 to 3.11. pybsn with Python 3.6 support has been deprecated, and may be removed in the next release.

pip3 install pybsn

As of version 0.4.0, pybsn is only compatible with python 3.6 or newer.

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PyBSN Repl - Interactive Shell

pybsn-repl is a powerful, interactive shell for the REST API. It is based on and requires python3.5 or newer and ipython 7.9 or newer.

Installing Python3 on Mac

Homebrew is a recommended option to install python3 on mac.

After you install homebrew, install python3 with

brew install python

Installing IPython 7

pip3 install ipython

Running pybsn-repl

./bin/pybsn-repl -H <controller_host> -u <user> -p <passwd>

Note: pybsn-repl requires pybsn to be available; you can either install it from pip3 (see above); or use it directly from the source by prefixing the command with PYTHONPATH=<dir>, e.g.,

~/dev/pybsn $ PYTHONPATH=. ./bin/pybsn-repl -H <controller_host> -u <user> -p <passwd>

Using pybsn-repl

PyBSN-repl presents an IPython shell to interact with the REST API.

It accepts any python expressions, and exposes the following variables as primary entry points:

• ctrl: BigDbClient instance
• root: ctrl.root - a reference to the root node.

Node Hierarchy

You can explore the DB Rest API anchored on root. Child nodes in the rest API are dynamically exposed as child objects / properties of root. Hyphens (-) in the REST API are converted to _ for python.

E.g.,

• root.core.switch references the node controller/core/switch
• root.core.switch_config references the node controller/core/switch-config

Nodes that cannot be represented as properties because their name is a python keyword (e.g., global), can be accessed by dictionary style access, e.g.

root.os.config["global"]

Operations on nodes:

• add a # at the end of the line to show the Schema at the given node.

In [12]: root.core.switch_config#
controller/core/switch-config (list)
  # List of switches that are configured in the controller. Switch
  # configuration is keyed by a logical switch name and is bound to a
  # specific physical switch by its dpid
  banner : string (config)
    # The switch banner, which is displayed on login.
  description : string (config)
    # A description of this configured switch.
[...]

• invoke the node as a functon <node>() to perform a GET request against the node:

In [8]: root.core.switch_config()
Out[8]:
[{'mac-address': '52:54:00:21:4c:56',
  'name': 'sn1',
  'role': 'service',
  'shutdown': False},
 {'mac-address': '52:54:00:c1:40:1e',
  'name': 'swl1',
  'role': 'bigtap',
  'shutdown': False}]

• call match(<property>=<value>) to add an exact-match predicate to the query:

In [11]: root.core.switch_config.match(name='sn1')()
Out[11]:
[{'mac-address': '52:54:00:21:4c:56',
  'name': 'sn1',
  'role': 'service',
  'shutdown': False}]

• call HTTP methods on the node to mutate data:
  • node.post(data) - inserts data at the node
  • node.put(data) - replaces the node entirely with the new data
  • node.patch(data) - selectively updates the node with the given data, leaving unspecified values untouched
  • node.delete() - delete the node

In these examples, data is a JSON serializable object, often a dictionary. Note that the dictionary keys must be in schema format at present (i.e., with hyphens, some-long-property not some_long_property).

• call node.rpc(input_data) to make an RPC call to the RPC specified in the node.

input_data is a JSON serializable object, often a dictionary. Note that the dictionary keys must be in schema format at present (i.e., with hyphens, some-long-property not some_long_property).

The output/result of the RPC returned as a dictionary.

More Examples:

# Show the schema for controller.core.switch
root.core.switch#

# Get info for all switches
root.core.switch()

# Get info for a specific switch
root.core.switch.match(name="leaf0a").get()

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Example Programmatic Usage

import pybsn

# recommended: use with an access token, generated for the user with
# conf t
# user admin
#    access-token my-api-token
# >>> access-token : <token>
client = pybsn.connect(host=args.host, token="<token>", verify_tls=True|False)

# alternatively, can use user-name password
client = pybsn.connect(host=args.host, username="<user>", password="<password>", verify_tls=True|False)

# can use client directly to make requests:
## get all switch configs
switch_configs = client.get("core/switch-config")
## get config of a particular switch
particular_config = client.get('core/switch-config[name="leaf-1a"]')
## insert a new switch config
client.post("core/switch-config", data={ "name": "leaf-1a", "mac-address": "01:02:03:04:05:06" } )
## disconnect a switch (RPC)
client.rpc('core/switch[name="leaf-1a"]/disconnect')

# Or, can use the node abstraction layer for more convenient access:

root = client.root

## get all switch configs
switch_configs = root.core.switch_config()
## get config of a particular switch
particular_config = root.core.switch_config.match(name="leaf-1a")
## insert a new switch config
root.core.switch_config.post({ "name": "leaf-1a", "mac-address": "01:02:03:04:05:06" })
## disconnect a switch (RPC)
root.core.switch.match(name="leaf-1a").disconnect.rpc()

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Contributing

If you'd like to contribute a feature or bugfix: Thanks! To make sure your fix/feature has a high chance of being included, please read the following guidelines:

1. Post a pull request.
2. Make sure there are tests! We will not accept any patch that is not tested. It's a rare time when explicit tests aren't needed. If you have questions about writing tests for pybsn, please open a GitHub issue.

Please see CONTRIBUTING.md for more details on contributing and running test.

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License

Please see LICENSE at the top level of the repository.