Common components are integrated in dd-trace-php by importing the source code from the libdatadog repository. As stated in the contributing file the code is imported by using git submodules which downloads the sources into libdatadog folder located at the project’s root directory.
The rust sources are compiled to assemble a static library named libddtrace_php.a, this library contains the necessary functionality to:
- Sidecar initialization and communication.
- Sending telemetry.
- Common functionality like container identification and runtime id generation.
The compilation process is handled by a compile script which is instantiated from the Makefile generated from config.m4. Once the library is assembled its contents are linked in ddtrace.so which is the main objective in the Makefile. This library is the extension which the PHP engine will load at runtime in order to provide all tracing functionality.
Upon adding new modules in the libdatadog repository there is the need to create the neccessary glue code in the php side to use those new modules. For that purpose you'll need to follow the next steps:
- Modify the project file in components-rs to add the new dependency.
- Add the necessary code in components-rs to expose the functionality.
- Modify the compile script if any new configuration needs to be added to the compilation process.
- Add the new module to the
RUST_FILESvariable in the Makefile.