Hacking Python SDK » History » Version 13

Version 12 (Tom Clegg, 08/26/2014 09:41 AM) → Version 13/23 (Tom Clegg, 08/26/2014 09:43 AM)

h1. Hacking Python SDK


h2. Prerequisites

The FUSE driver requires associated libraries to build:

sudo apt-get install libattr1-dev libfuse-dev pkg-config fuse
sudo adduser "$USER" fuse
sudo chmod g+rw /dev/fuse
sudo chown root:fuse /dev/fuse

After installing @fuse@ and adding yourself to the @fuse@ group, you need to start a new login session. Make sure the @groups@ command reports that you're in the @fuse@ group.

h2. Get the source code

git clone https://github.com/curoverse/arvados.git

h2. virtualenv

virtualenv helps you isolate the dependencies for a specific package or environment, much like Bundler does for our Rails applications. The recommended way to deploy is to build a virtualenv for Arvados development.

To build the virtualenv, run:

$ virtualenv --setuptools VENVDIR

(@VENVDIR@ can be a directory anywhere you like, although best practice is to keep it outside your source directory.)

To set up the shell to use the isolated virtualenv environment, run:

$ source VENVDIR/bin/activate

To learn more about using and configuring virtualenv, read the "virtualenv usage documentation":https://virtualenv.pypa.io/en/latest/virtualenv.html#usage.

h2. Run tests

# Set up the environment to use a dedicated virtualenv
# Run the client library test suite
# Build a client library package and install it to the virtualenv
# Run the FUSE driver test suite
# Build a FUSE driver package and install it to the virtualenv

Note: The test suite brings up a Keep server and an API server to run tests against. For best results:
* Try [[Hacking Keep]] and [[Hacking API Server]] to make sure you have all the right dependencies for running the Keep and API servers.
* Make sure you have a blob_signing_key in services/api/config/application.yml
* Install the keepstore binary.
** Make sure your GOPATH points somewhere, e.g.: @export GOPATH=~/gocode; mkdir -p $GOPATH@
** Install keepstore: @go get git.curoverse.com/arvados.git/services/keepstore@
** (if you don't do anything special, this fetches "master" from git.curoverse.com -- if you want to build a version of keepstore with local modifications, see [[Hacking Keep]])

Script (make sure to edit the first line to refer to your virtualenv):

source VENVDIR/bin/activate

cd ~/arvados/sdk/python
python setup.py test
python setup.py egg_info -b ".$(git log --format=format:%ct.%h -n1 .)" sdist rotate --keep=1 --match .tar.gz
pip install dist/arvados-python-client-0.1.*.tar.gz

cd ~/arvados/services/fuse
python setup.py test
python setup.py egg_info -b ".$(git log --format=format:%ct.%h -n1 .)" sdist rotate --keep=1 --match .tar.gz
pip install dist/arvados_fuse-0.1.*.tar.gz

h3. Run a single test or test class

source VENVDIR/bin/activate
cd ~/arvados/sdk/python

# One test module class
python setup.py test --test-suite tests.test_keep_locator

# One test class
python setup.py test --test-suite tests.test_keep_locator.ArvadosKeepLocatorTest

# One test case
python setup.py test --test-suite

h2. Logging

The Python SDK uses Python's built-in logging module to log errors, warnings, and debug messages. The arvados module sets up logging for messages under "arvados" based on local configuration (e.g., the @ARVADOS_DEBUG@ setting). Other SDK modules and command-line tools should @import arvados@ and then send messages to a logger under "arvados" to ensure consistent log handling. Typical setup looks like this:

<pre><code class="python">
import arvados
import logging

logger = logging.getLogger('arvados.YOURTHING')

Once you've set this up, you can send messages to the logger using methods like @logger.debug()@ and @logger.error()@. See the "Logger class documentation":https://docs.python.org/2/library/logging.html#logger-objects for full details.

Command-line scripts may reconfigure the @arvados.logger@ object based on additional configuration like command-line switches. @services/fuse/bin/arv-mount@ demonstrates adjusting the level and setting a custom log handler.