# Zenoh

[Zenoh](https://zenoh.io) is a pub/sub/query protocol unifying data in motion, data at rest and computations. You need two pieces - the `eclipse-zenoh` python library and the Zenoh daemon (`zenohd`). Your Python project needs `eclipse-zenoh`, which is already added to OM1's `pyproject.toml`.

#### Mac

Install the Zenoh router:

```bash
$ brew tap eclipse-zenoh/homebrew-zenoh
$ brew install zenoh
```

#### Linux

Install the Zenoh router:

```bash
$ echo "deb [trusted=yes] https://download.eclipse.org/zenoh/debian-repo/ /" | sudo tee -a /etc/apt/sources.list > /dev/null
$ sudo apt update
$ sudo apt install zenoh
```

### Starting/testing the Router

In a separate terminal window, start the router:

```bash
# inside OM1
zenohd -c robot_storage.json5
```

Testing:

```bash
zenohd --help
```

### Installing the Persistent Backend

See <https://github.com/eclipse-zenoh/zenoh-backend-filesystem?tab=readme-ov-file#how-to-install-it>

On Mac, you might need to allow `libzenoh_backend_fs.dylib` to run via `Privacy and Security`. Just try to run it separately - e.g. via the terminal and then `approve` the various popup messages. Once you have run `libzenoh_backend_fs.dylib` once, it will be cached and then `zenoh` can find it the next time. This is good, but can be confusing if you are trying to upgrade `libzenoh_backend_fs.dylib` but it keeps using an older cached version.

The RocksDB database is where ever you set the path to:

```bash
export ZENOH_BACKEND_FS_ROOT=$PWD/zenohdb/
```

The `RocksDB version: 9.9.3` is set up at `ZENOH_BACKEND_FS_ROOT`, where it creates a system of folders. For example, a PUT to `/robot/audio` creates a file at `/zenohdb/robot/audio`, which then contains the most recent value of the `robot/audio` key.

### Using the REST API at ::9500

You can use `curl` to publish and query the **latest** keys/values:

```bash
# Put values that will be stored under ${ZENOH_BACKEND_FS_ROOT}/robot
curl -X PUT -d "HELLO WORLD" http://localhost:9500/robot
curl -X PUT -d "HELLO WORLD A" http://localhost:9500/robot/audio

# Retrieve the values
curl http://localhost:9500/robot
curl http://localhost:9500/robot/audio
```

To be clear, the system only saves the most recent key/value pair.


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://docs.openmind.com/robotics/zenoh.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.