Hacking Python SDK » History » Version 17
Hacking Python SDK¶
- Table of contents
- Hacking Python SDK
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
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
Get the source code¶
cd git clone https://github.com/curoverse/arvados.git
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.
- 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
- 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 $GOPATH
- Install keepstore:
go get git.curoverse.com/arvados.git/services/keepstore
- (if you don't do anything special, this fetches "master" from git.curoverse.com -- if you want to build a version of keepstore with local modifications, see Hacking Keep)
- Make sure your GOPATH points somewhere, e.g.:
Script (make sure to edit the first line to refer to your virtualenv):
source VENVDIR/bin/activate cd ~/arvados/sdk/python python setup.py test python setup.py egg_info -b ".$(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 ".$(git log --format=format:%ct.%h -n1 .)" sdist rotate --keep=1 --match .tar.gz pip install dist/arvados_fuse-0.1.*.tar.gz
Run a single test or test class¶
source VENVDIR/bin/activate cd ~/arvados/sdk/python # One test module python setup.py test --test-suite tests.test_keep_locator # One test class python setup.py test --test-suite tests.test_keep_locator.ArvadosKeepLocatorTest # One test case python setup.py test --test-suite tests.test_keep_locator.ArvadosKeepLocatorTest.base_locators
Builds and versioning¶
When we build each Python package, the version number is
0.1.$(git log --format=format:%ct.%h -n1 .), where the current directory is the package directory. In plain English, it looks at the most recent git commit that affected the package, and then the version number is
0.1.[commit's timestamp in seconds since the Epoch].[commit's short hash].
This means that if you want to make changes in one package and refer to it somewhere else (e.g., have the FUSE package depend on a specific SDK version), you should commit your changes to the original package before anything else. Then you can consistently refer to the metadata from that dedicated commit in subsequent changes.
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:
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.error(). See the Logger class documentation 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.
Python buffer protocol¶
Notes on managing buffers efficiently in Python, we don't use this in the python sdk as of this writing (but we might).
Example using bytearray() to allocate a buffer, memoryview() to create a writable slice, and readinto() to write directly to the buffer slice:
>>> b = bytearray(20) >>> c = memoryview(b) >>> f = open("python.txt", "r") >>> f.readinto(c[5:10]) 5 >>> b bytearray(b"\x00\x00\x00\x00\x00I\'ve \x00\x00\x00\x00\x00\x00\x00\x00\x00\x00")