Skip to main content
Donate to the Python Software Foundation or Purchase a PyCharm License to Benefit the PSF! Donate Now

CADC VOS Class Libraries

Project description


.. image::

vos is a set of python modules and scripts that ease access to VOSpace.

The default installation of vos is tuned for accessing the VOSpace
provided by the `Canadian Advanced Network For Astronomical
Research <>`__ (CANFAR)

VOSpace is a Distributed Cloud storage service for use in Astronomy.

There are two ways to use vos:

1. access VOSpace using the command-line script: eg. *vcp*
2. use the vos module inside a Python script: ``import vos``

Authentication to the CANFAR VOSpace service is performed using X509
security certificates, header tokens or username/password pairs. The
authentication system is managed by the CADC Group Management Service

To retrieve an X509 security certificate for use with the ``vos`` tools
use the *getCert* script included with this package.

Additional information is available in the `CANFAR
documentation <>`__

System Requirments

- A CANFAR VOSpace account (required for WRITE access, READ access can
be anonymous)
- fuse OR OSX-FUSE (see additional documentation, only required for
filesystem based access, not for command line or programmatic)
- python2.6 or later


vos is distributed via `PyPI/vos <>`__ and PyPI
is the most direct way to get the latest stable release:

``pip install vos --upgrade --user``

Or, you can retrieve the `github <>`__ distribution
and use

``python install --user``


1. Get a `CANFAR
account <>`__
2. Install the vos package.
3. Retrieve a X509/SSL certificate using the ``getCert``
script installed as part of the ``cadcutils`` package that is automatically installed wiht vos.
4. Example Usage.

1. Commandline usage:

- ``vls -l vos:`` [List a vospace]
- ``vcp vos:jkavelaars/test.txt ./`` [copies test.txt to the
local directory from vospace]
- ``vchmod g+q vos:VOSPACE/foo/bar.txt 'GROUP1, GROUP2, GROUP3' `` to give three user GROUPs permission
to write to this file.
- ``vmkdir --help`` [get a list of command line options and
- ``vmkdir``, ``vrm``, ``vrmdir``, ``vsync`` ``vcat``, ``vchmod``
and ``vln``
- The complete list of ``vos`` commmand line tools can be found using ``pydoc vos.commands``

2. In a Python script (the example below provides a listing of a
vospace container)


import vos
client = vos.Client()


A virtual environment (**venv**) is recommended to set up external
dependencies without installing them system-wide. Following `these
instructions <>`__,
install **virtualenv**:


$ pip install virtualenv

Next, create, and activate a local **venv** (this example uses


$ virtualenv venv
$ source venv/bin/activate

Setup the new development environment for testing by installing the appropriate packages:


$ pip install -r dev_requirements.txt

The test environment is built into the ** so that conducting unit-tests can be achieved like so:


$ python test

If you would like versbose output formated as a web page, for example,
you can add options to the test call:


$ python test --addopts '--cov-report html:cov_html --cov=vos'

The same option attribute can be used to pass other arguments to py.test
that is executing the test. To run specific only tests for example:


$ python test --addopts 'vos/test/'

Each time you resume work on the project and want to use the **venv**
(e.g., from a new shell), simply re-activate it:


$ source venv/bin/activate

When done, just issue a


$ deactivate

command to deactivate the virtual environment.

Integration Tests

The integration tests are, at present, designed to run only with the
CADC VOSpace. Tests assume that vos and/or vofs packages have been

Activate the **venv** and install vos


$ source venv/bin/activate.csh
$ pip install vos

Run the tests:

$ ./test/scripts/vospace-all.tcsh

Project details

Release history Release notifications

Download files

Download the file for your platform. If you're not sure which to choose, learn more about installing packages.

Filename, size & hash SHA256 hash help File type Python version Upload date
vos-3.0.12.tar.gz (62.1 kB) Copy SHA256 hash SHA256 Source None

Supported by

Elastic Elastic Search Pingdom Pingdom Monitoring Google Google BigQuery Sentry Sentry Error logging AWS AWS Cloud computing DataDog DataDog Monitoring Fastly Fastly CDN SignalFx SignalFx Supporter DigiCert DigiCert EV certificate StatusPage StatusPage Status page