Below you will find a brief overview of each subdir in the source tree in alphabetical order.
/control_plane
:
Local control plane. Functions to start, configure and stop pageserver and postgres instances running as a local processes. Intended to be used in integration tests and in CLI tools for local installations.
/docs
:
Documentation of the Zenith features and concepts. Now it is mostly dev documentation.
/monitoring
:
TODO
/pageserver
:
Zenith storage service. The pageserver has a few different duties:
- Store and manage the data.
- Generate a tarball with files needed to bootstrap ComputeNode.
- Respond to GetPage@LSN requests from the Compute Nodes.
- Receive WAL from the WAL service and decode it.
- Replay WAL that's applicable to the chunks that the Page Server maintains
For more detailed info, see /pageserver/README
/proxy
:
Postgres protocol proxy/router. This service listens psql port, can check auth via external service and create new databases and accounts (control plane API in our case).
/test_runner
:
Integration tests, written in Python using the pytest
framework.
/vendor/postgres
:
PostgreSQL source tree, with the modifications needed for Neon.
/vendor/postgres/contrib/neon
:
PostgreSQL extension that implements storage manager API and network communications with remote page server.
/vendor/postgres/contrib/neon_test_utils
:
PostgreSQL extension that contains functions needed for testing and debugging.
/safekeeper
:
The zenith WAL service that receives WAL from a primary compute nodes and streams it to the pageserver. It acts as a holding area and redistribution center for recently generated WAL.
For more detailed info, see /safekeeper/README
/workspace_hack
:
The workspace_hack crate exists only to pin down some dependencies.
We use cargo-hakari for automation.
/zenith
Main entry point for the 'zenith' CLI utility. TODO: Doesn't it belong to control_plane?
/libs
:
Unites granular neon helper crates under the hood.
/libs/postgres_ffi
:
Utility functions for interacting with PostgreSQL file formats. Misc constants, copied from PostgreSQL headers.
/libs/utils
:
Generic helpers that are shared between other crates in this repository.
A subject for future modularization.
/libs/metrics
:
Helpers for exposing Prometheus metrics from the server.
Note that Debian/Ubuntu Python packages are stale, as it commonly happens, so manual installation of dependencies is not recommended.
A single virtual environment with all dependencies is described in the single Pipfile
.
- Install Python 3.9 (the minimal supported version) or greater.
- Our setup with poetry should work with newer python versions too. So feel free to open an issue with a
c/test-runner
label if something doesn't work as expected. - If you have some trouble with other version you can resolve it by installing Python 3.9 separately, via pyenv or via system package manager e.g.:
# In Ubuntu sudo add-apt-repository ppa:deadsnakes/ppa sudo apt update sudo apt install python3.9
- Our setup with poetry should work with newer python versions too. So feel free to open an issue with a
- Install
poetry
- Exact version of
poetry
is not important, see installation instructions available at poetry's website`.
- Exact version of
- Install dependencies via
./scripts/pysync
.- Note that CI uses specific Python version (look for
PYTHON_VERSION
here) so if you have different version some linting tools can yield different result locally vs in the CI. - You can explicitly specify which Python to use by running
poetry env use /path/to/python
, e.g.poetry env use python3.9
. This may also disable theThe currently activated Python version X.Y.Z is not supported by the project
warning.
- Note that CI uses specific Python version (look for
Run poetry shell
to activate the virtual environment.
Alternatively, use poetry run
to run a single command in the venv, e.g. poetry run pytest
.
We force code formatting via yapf
and type hints via mypy
.
Run the following commands in the repository's root (next to setup.cfg
):
poetry run yapf -ri . # All code is reformatted
poetry run mypy . # Ensure there are no typing errors
WARNING: do not run mypy
from a directory other than the root of the repository.
Otherwise it will not find its configuration.
Also consider:
- Running
flake8
(or a linter of your choice, e.g.pycodestyle
) and fixing possible defects, if any. - Adding more type hints to your code to avoid
Any
.
To add new package or change an existing one you can use poetry add
or poetry update
or edit pyproject.toml
manually. Do not forget to run poetry lock
in the latter case.
More details are available in poetry's documentation.