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Class Libraries for VOSpace file system

Project description

vosfs is a python module that allows a VOSpace service to be used as a file system.

The default installation of vosfs 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. make VOSpace appear as mounted filesystem: mountvofs
  2. use the vosfs module inside a Python script: import vosfs

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 (GMS).

To retrieve an X509 security certificate for use with the vosfs tools use the cadc-get-cert script included with the cadcutils 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


vosfs is distributed via PyPI/vos and PyPI is the most direct way to get the latest stable release:

pip install vosfs --upgrade --user

Or, you can retrieve the github distribution and use

python install --user


  1. Get a CANFAR account
  2. Install the vosfs package.
  3. Retrieve a X509/SSL certificate using the installed in cadc-get-cert script.
  4. Example Usage.
    1. For filesystem usage: mountvofs mounts the CADC VOSpace root Container Node at /tmp/vospace and initiates a 5GB cache in the users home directory (${HOME}/vos_). fusermount -u /tmp/vospace (LINUX) or umount /tmp/vospace (OS-X) unmounts the file system. VOSpace does not have a mapping of your unix users IDs and thus files appear to be owned by the user who issued the ‘mountvofs’ command.


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 bash):

$ 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=vosfs'

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 the vofs package has been installed.

Activate the venv and install vofs

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

Run the tests:

``` $ ./test/scripts/vospace-mountvospace-atest.tcsh

Project details

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