We welcome community contributions to MLflow. This page describes how to develop/test your changes to MLflow locally.
The majority of the MLflow codebase is in Python. This includes the CLI, Tracking Server, Artifact Repositories (e.g., S3 or Azure Blob Storage backends), and of course the Python fluent, tracking, and model APIs.
First, install the Python MLflow package from source - this is required for developing & testing changes across all languages and APIs. We recommend installing MLflow in its own conda environment by running the following from your checkout of MLflow:
conda create --name mlflow-dev-env python=3.6
source activate mlflow-dev-env
pip install -r dev-requirements.txt
pip install -r test-requirements.txt
pip install -e . # installs mlflow from current checkoutEnsure Docker is installed.
npm is required to run the Javascript dev server and the tracking UI.
You can verify that npm is on the PATH by running npm -v, and
install npm if needed.
If contributing to MLflow's R APIs, install R. For changes to R
documentation, also install pandoc 2.2.1 or above,
verifying the version of your installation via pandoc --version. If using Mac OSX, note that
the homebrew installation of pandoc may be out of date - you can find newer pandoc versions at
https://github.com/jgm/pandoc/releases.
If contributing to MLflow's Java APIs or modifying Java documentation, install Java and Apache Maven.
Before running the Javascript dev server or building a distributable wheel, install Javascript dependencies via:
cd mlflow/server/js
npm install
cd - # return to root repository directoryIf modifying dependencies in mlflow/server/js/package.json, run npm update within
mlflow/server/js to install the updated dependencies.
Certain MLflow modules are implemented in Java, under the mlflow/java/ directory.
These are the Java Tracking API client (mlflow/java/client) and the Model Scoring Server
for Java-based models like MLeap (mlflow/java/scoring).
Other Java functionality (like artifact storage) depends on the Python package, so first install the Python package in a conda environment as described above. Install the Java 8 JDK (or above), and download and install Maven. You can then build and run tests via:
cd mlflow/java
mvn compile testIf opening a PR that makes API changes, please regenerate API documentation as described in Writing Docs and commit the updated docs to your PR branch.
The mlflow/R/mlflow directory contains R wrappers for the Projects, Tracking and Models
components. These wrappers depend on the Python package, so first install
the Python package in a conda environment:
# Note that we don't pass the -e flag to pip, as the R tests attempt to run the MLflow UI
# via the CLI, which will not work if we run against the development tracking server
pip install .Install R, then run the following to install dependencies for building MLflow locally:
cd mlflow/R/mlflow
NOT_CRAN=true Rscript -e 'install.packages("devtools", repos = "https://cloud.r-project.org")'
NOT_CRAN=true Rscript -e 'devtools::install_deps(dependencies = TRUE)'Build the R client via:
R CMD build .Run tests:
R CMD check --no-build-vignettes --no-manual --no-tests mlflow*tar.gz
cd tests
NOT_CRAN=true LINTR_COMMENT_BOT=false Rscript ../.travis.R
cd -Run linter:
Rscript -e 'lintr::lint_package()'If opening a PR that makes API changes, please regenerate API documentation as described in Writing Docs and commit the updated docs to your PR branch.
When developing, you can make Python changes available in R by running (from mlflow/R/mlflow):
Rscript -e 'reticulate::conda_install("r-mlflow", "../../../.", pip = TRUE)'Please also follow the recommendations from the Advanced R - Style Guide regarding naming and styling.
Verify that the unit tests & linter pass before submitting a pull request by running:
./lint.sh
./travis/run-small-python-tests.sh
# Optionally, run large tests as well. Travis will run large tests on your pull request once
# small tests pass. Note: models and model deployment tests are considered "large" tests. If
# making changes to these components, we recommend running the relevant tests (e.g. tests under
# tests/keras for changes to Keras model support) locally before submitting a pull request.
./travis/run-large-python-tests.shPython tests are split into "small" & "large" categories, with new tests falling into the "small" category by default. Tests that take 10 or more seconds to run should be marked as large tests via the @pytest.mark.large annotation. Dependencies for small and large tests can be added to travis/small-requirements.txt and travis/large-requirements.txt, respectively.
We use pytest to run Python tests.
You can run tests for one or more test directories or files via
pytest [--large] [file_or_dir] ... [file_or_dir], where specifying --large tells pytest to
run tests annotated with @pytest.mark.large. For example, to run all pyfunc tests
(including large tests), you can run:
pytest tests/pyfunc --largeNote: Certain model tests are not well-isolated (can result in OOMs when run in the same Python
process), so simply invoking pytest or pytest tests may not work. If you'd like to
run multiple model tests, we recommend doing so via separate pytest invocations, e.g.
pytest --verbose tests/sklearn --large && pytest --verbose tests/tensorflow --large
Note also that some tests do not run as part of PR builds on Travis. In particular, PR builds exclude:
- Tests marked with @pytest.mark.requires_ssh. These tests require that passwordless SSH access to localhost be enabled, and can be run via
pytest --requires-ssh.- Tests marked with @pytest.mark.release. These tests can be run via
pytest --release.
If opening a PR that changes or adds new APIs, please update or add Python documentation as described in Writing Docs and commit the docs to your PR branch.
To build protobuf files, simply run generate-protos.sh. The required protoc version is 3.6.0.
Verify that .proto files and autogenerated code are in sync by running ./test-generate-protos.sh.
MLflow's Tracking component supports storing experiment and run data in a SQL backend. To make changes to the tracking database schema, run the following from your checkout of MLflow:
# starting at the root of the project
$ pwd
~/mlflow
$ cd mlflow
# MLflow relies on Alembic (https://alembic.sqlalchemy.org) for schema migrations.
$ alembic -c mlflow/store/db_migrations/alembic.ini revision -m "add new field to db"
Generating ~/mlflow/mlflow/store/db_migrations/versions/b446d3984cfa_add_new_field_to_db.pyThese commands generate a new migration script (e.g. at
~/mlflow/mlflow/alembic/versions/12341123_add_new_field_to_db.py) that you should then edit to add
migration logic.
We recommend Running the Javascript Dev Server - otherwise, the tracking frontend will request
files in the mlflow/server/js/build directory, which is not checked into Git.
Alternatively, you can generate the necessary files in mlflow/server/js/build as described in
Building a Distributable Artifact.
Install Node Modules, then run the following:
In one shell:
mlflow uiIn another shell:
cd mlflow/server/js
npm startThe MLflow Tracking UI will show runs logged in ./mlruns at http://localhost:3000.
Install Node Modules, then run the following:
Generate JS files in mlflow/server/js/build:
cd mlflow/server/js
npm run buildBuild a pip-installable wheel in dist/:
cd -
python setup.py bdist_wheelFirst, install dependencies for building docs as described in Prerequisites.
To generate a live preview of Python & other rst documentation, run the following snippet. Note that R & Java API docs must be regenerated separately after each change and are not live-updated; see subsequent sections for instructions on generating R and Java docs.
cd docs
make livehtmlGenerate R API rst doc files via:
cd docs
make rdocsGenerate Java API rst doc files via:
cd docs
make javadocsGenerate API docs for all languages via:
cd docs
make htmlIf changing existing Python APIs or adding new APIs under existing modules, ensure that references
to the modified APIs are updated in existing docs under docs/source. Note that the Python doc
generation process will automatically produce updated API docs, but you should still audit for
usages of the modified APIs in guides and examples.
If adding a new public Python module, create a corresponding doc file for the module under
docs/source/python_api - see here
for an example.