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# Pulsar Python client library

## Requirements

- Python >= 3.7
- A C++ compiler that supports C++11
- CMake >= 3.18
- [Pulsar C++ client library](https://github.com/apache/pulsar-client-cpp)
- [PyBind11](https://github.com/pybind/pybind11)

PyBind11 is a header-only library and a submodule, so you can simply download the submodule so that CMake can find this dependency.

```bash
git submodule update --init
```

You can also download the pybind11 directly like:

```bash
pip3 install pyyaml
export PYBIND11_VERSION=$(./build-support/dep-version.py pybind11)
curl -L -O https://github.com/pybind/pybind11/archive/refs/tags/v${PYBIND11_VERSION}.tar.gz
tar zxf v${PYBIND11_VERSION}.tar.gz
mv pybind11-${PYBIND11_VERSION} pybind11
```

After that, you only need to install the Pulsar C++ client dependency into the system path. You can [install the pre-built binaries](https://pulsar.apache.org/docs/next/client-libraries-cpp/#installation) or [build from source](https://github.com/apache/pulsar-client-cpp#compilation).

## Install the Python wheel

Make sure the PyBind11 submodule has been downloaded and the Pulsar C++ client has been installed. Then run the following commands:

```bash
cmake -B build
cmake --build build 
cmake --install build
python3 ./setup.py bdist_wheel
python3 -m pip install dist/pulsar_client-*.whl --force-reinstall
```

> **NOTE**
>
> 1. Here a separate `build` directory is created to store all CMake temporary files. However, the `setup.py` requires the `_pulsar.so` is under the project directory.
> 2. Add the `--force-reinstall` option to overwrite the existing Python wheel in case your system has already installed a wheel before.
> 3. On Windows, the Python command is `py` instead of `python3`.

## Running examples

You can run `python3 -c 'import pulsar'` to see whether the wheel has been installed successfully. If it failed, check whether dependencies (e.g. `libpulsar.so`) are in the system path. If not, make sure the dependencies are in `LD_LIBRARY_PATH` (on Linux) or `DYLD_LIBRARY_PATH` (on macOS).

Then you can run examples as a simple end-to-end test.

```bash
# In terminal 1
python3 ./examples/consumer.py
```

```bash
# In terminal 2
python3 ./examples/producer.py
```

Before executing the commands above, you must ensure the Pulsar service is running. See [here](https://pulsar.apache.org/docs/getting-started-standalone) for quick start.

## Unit tests

Before running the unit tests, you must run a Pulsar service with all things set up:

```bash
./build-support/pulsar-test-service-start.sh
```

The command above runs a Pulsar standalone in a Docker container. You can run `./build-support/pulsar-test-service-stop.sh` to stop it.

Run all unit tests:

```bash
./tests/run-unit-tests.sh
```

Run a single unit test (e.g. `PulsarTest.test_tls_auth`):

```bash
python3 ./tests/pulsar_test.py 'PulsarTest.test_tls_auth'
```

## Generate API docs

Pulsar Python Client uses [pydoctor](https://github.com/twisted/pydoctor) to generate API docs. To generate by yourself, run the following command in the root path of this repository:

```bash
sudo python3 -m pip install pydoctor
pydoctor --make-html \
  --html-viewsource-base=https://github.com/apache/pulsar-client-python/tree/<release-version-tag> \
  --docformat=numpy --theme=readthedocs \
  --intersphinx=https://docs.python.org/3/objects.inv \
  --html-output=<path-to-apidocs> \
  pulsar
```