# Topology Renderer

`p4_topology_diagram.py` is an optional Python renderer for P4 server topology.
It produces Mermaid, Markdown, AsciiDoc, interactive HTML, and SVG output.
For the built-in pure-Go SVG renderer, see the [main README](../README.md#topology).

The script runs `p4 servers` and `p4 topology -t 2`, then matches the output.
It must be run by a logged-in P4 user with `super` privileges.

## Download

Download [p4_topology_diagram.py](https://swarm.workshop.perforce.com/downloads/guest/perforce_software/p4survey/p4_topology_diagram.py).

## Installation

The script requires Python 3 and `p4python`:

```bash
if ! command -v uv >/dev/null 2>&1; then
    curl -LsSf "https://astral.sh/uv/install.sh" | sh
    export PATH="$HOME/.local/bin:$PATH"
fi
uv python install
uv venv .venv
source .venv/bin/activate
uv pip install p4python
```

`fast-sugiyama` is optional and gives a better automatic SVG layout. Graphviz
enables its named layout engines.

```bash
uv pip install fast-sugiyama
```

## Usage

Run the script with the current `P4PORT` and `P4USER` environment settings:

```bash
./p4_topology_diagram.py
```

It writes JSON, Mermaid, Markdown, AsciiDoc, HTML, and SVG files by default.
To render existing data without contacting P4, use:

```bash
./p4_topology_diagram.py --input-json p4_topology_data.json
```

Use `--layout` to choose `auto`, `sugiyama`, `grid`, or a Graphviz engine such
as `dot` or `sfdp`. Run `./p4_topology_diagram.py --help` for the complete
option reference.

## Example

Produced from [p4_topology.svg](../images/p4_topology.svg):

![Example of a generated SVG diagram that was lightly rearranged and saved](../images/p4_topology.png)