If you are doing development on the Ray codebase, the following tips may be helpful.
Speeding up compilation: Be sure to install Ray with
cd ray/python pip install -e . --verbose
-emeans “editable”, so changes you make to files in the Ray directory will take effect without reinstalling the package. In contrast, if you do
python setup.py install, files will be copied from the Ray directory to a directory of Python packages (often something like
/home/ubuntu/anaconda3/lib/python3.6/site-packages/ray). This means that changes you make to files in the Ray directory will not have any effect.
If you run into Permission Denied errors when running
pip install, you can try adding
--user. You may also need to run something like
sudo chown -R $USER /home/ubuntu/anaconda3(substituting in the appropriate path).
If you make changes to the C++ files, you will need to recompile them. However, you do not need to rerun
pip install -e .. Instead, you can recompile much more quickly by doing
cd ray/python/ray/core make -j8
Starting processes in a debugger: When processes are crashing, it is often useful to start them in a debugger (
gdbon Linux or
lldbon MacOS). See the latest discussion about how to do this here.
Running tests locally: Suppose that one of the tests (e.g.,
runtest.py) is failing. You can run that test locally by running
python test/runtest.py. However, doing so will run all of the tests which can take a while. To run a specific test that is failing, you can do
cd ray python test/runtest.py APITest.testKeywordArgs
When running tests, usually only the first test failure matters. A single test failure often triggers the failure of subsequent tests in the same script.
Running linter locally: To run the Python linter on a specific file, run something like
flake8 ray/python/ray/worker.py. You may need to first run
pip install flake8.
Inspecting Redis shards by hand: To inspect the primary Redis shard by hand, you can query it with commands like the following.
r_primary = ray.worker.global_worker.redis_client r_primary.keys("*")
To inspect other Redis shards, you will need to create a new Redis client. For example (assuming the relevant IP address is
127.0.0.1and the relevant port is
1234), you can do this as follows.
import redis r = redis.StrictRedis(host='127.0.0.1', port=1234)
You can find a list of the relevant IP addresses and ports by running
r_primary.lrange('RedisShards', 0, -1)