README
¶
Datadog Agent RtLoader
CPython embedding/extending backend with support for multiple Python versions.
Concepts
RtLoader is a C++ wrapper around the CPython API with a C89-compatible public API
that can be used by foreign languages like Go. In order to provide support for
multiple Python versions, RtLoader fully abstracts Python in order to decouple client
applications and CPython. Which Python version to use can be decided at runtime,
RtLoader will dlopen the proper backend libraries accordingly.
Architecture
libdatadog-agent-rtloader
RtLoader exposes its C89-compatible API through include/datadog_agent_rtloader.h. By
using the make2 and make3 functions, the corresponding Python backend will
be loaded at runtime. Under the hood the library provides RtLoader, a C++ interface
that must be implemented by any supported backend, see include/rtloader.h for details.
Two and Three
libdatadog-agent-three and libdatadog-agent-two libraries provide Python support
for extending and embedding by linking different versions of the CPython library.
Common
The common folder contains C/C++ modules that are compiled into both
libdatadog-agent-three and libdatadog-agent-two to avoid code duplication.
Most of the code used to extend the embedded interpreter is there.
Requirements
- C/C++ compiler
- Python 2.7.x development packages
- Python 3.8.x development packages
- Cmake version 3.12 or above
- Go compiler with
cgocapabilities to run the tests
Build
RtLoader can be built using CMake. Run the configurator/generator first:
cmake .
Then just run make to build the project.
Examples
Demo
Examples about how to use RtLoader are provided in form of a C application under demo. The application expects to find a
few things installed in the Python env. To easy development, a virtualenv can be used: the base check
and the Directory check have to be installed before running the demo, if you have a local clone of integrations-core
that should be a matter of pip install /path_to_integrations_core/datadog_checks_base and
pip install /path_to_integrations_core/directory. Then depending on which Python version your virtualenv provides, run:
OSX:
DYLD_LIBRARY_PATH=./three:./two ./demo/demo 2 $VIRTUAL_ENV
Unix
LD_LIBRARY_PATH=./three:./two ./demo/demo 2 $VIRTUAL_ENV
or
OSX
DYLD_LIBRARY_PATH=./three:./two ./demo/demo 3 $VIRTUAL_ENV
Unix
LD_LIBRARY_PATH=./three:./two ./demo/demo 3 $VIRTUAL_ENV
Test
Tests are written in Golang using cgo, run the testsuite from the root folder:
make -C test
Directories