adding transcoding example

Signed-off-by: gabrik <gabriele.baldoni@gmail.com>

README.md

@@ -44,3 +44,11 @@ The purpose of this example is to demonstrate how Zenoh-Flow can handle a
 complex dataflow graph, like a robotic application.
 
 Go to the [README](./montblanc/README.md) for instructions on how to run it.
+
+
+#### Transcoding
+
+The purpose of this example is to demonstrate how Zenoh-Flow can handle be used within a Zenoh
+router to transcode live data.
+
+Go to the [README](./transcoding/README.md) for instructions on how to run it.

transcoding/README.md

@@ -0,0 +1,119 @@
+
+# Zenoh-Flow for data transcoding.
+
+This document will guide you in building, installing and configuring Zenoh-Flow together with Zenoh for data transcoding.
+
+Note: this guide has been tested on Ubuntu 22.04 LTS
+## Prerequisites
+
+In order to be able to build and run Zenoh-Flow the following dependencies are needed:
+
+- build-essentials
+- python3-dev
+- python3-pip
+- python3-venv
+- clang
+- libclang-dev
+- rust
+- pkg-config
+
+Please make sure those dependencies are installed before proceeding.
+
+## Build Zenoh and Zenoh-Flow
+
+Clone the repositories and build:
+```
+cd ~
+
+git clone https://github.com/eclipse-zenoh/zenoh -b 0.7.2-rc
+cd zenoh
+cargo build --release --all-targets --features shared-memory
+
+cd ..
+git clone https://github.com/eclipse-zenoh/zenoh-flow -b v0.5.0-alpha.1
+cd zenoh-flow
+cargo build --release --all-targets
+
+cd ..
+git clone https://github.com/eclipse-zenoh/zenoh-flow-python -b v0.5.0-alpha.1
+cd zenoh-flow-python
+cargo build --release --all-targets
+
+cd zenoh-flow-python
+
+python3 -m venv venv
+source venv/bin/activate
+pip3 install -r requirements-dev.txt
+maturin build --release
+deactivate
+```
+
+## Install 
+
+Install Zenoh and Zenoh-Flow
+
+```
+cd ~
+
+sudo mkdir -p /etc/zenoh/
+sudo mkdir -p /var/zenoh-flow/python
+sudo mkdir -p /var/zenoh-flow/flows
+sudo mkdir -p /etc/zenoh-flow/extensions.d
+
+sudo cp zenoh/target/release/zenohd /usr/bin/
+sudo cp zenoh/target/release/libzenoh_plugin_*.so /usr/lib/
+
+sudo cp zenoh-flow/target/release/libzenoh_plugin_zenoh_flow.so /usr/lib/
+sudo cp zenoh-flow/target/release/zfctl /usr/bin/
+sudo cp zenoh-flow-python/target/release/libzenoh_flow_python_*_wrapper.so /var/zenoh-flow/python
+sudo cp zenoh-flow-python/01-python.zfext /etc/zenoh-flow/extensions.d/
+sudo cp zenoh-flow/zfctl/.config/zfctl-zenoh.json /etc/zenoh-flow/
+
+pip3 install ./zenoh-flow-python/target/wheels/eclipse_zenoh_flow-0.5.0a1-cp37-abi3-manylinux_2_34_x86_64.whl
+```
+
+## Start Runtime
+
+Copy the `zenoh-config.json` from this folder to `/etc/zenoh/zenoh.json`.
+
+Now you can start the Zenoh router with the Zenoh-Flow plugin.
+Open a terminal and run: `RUST_LOG=debug zenohd -c /etc/zenoh/zenoh.json`
+
+Then on another terminal run: `zfctl list runtimes`
+
+You should get an output similar to this:
+```
++----------------------------------+--------------------+--------+
+| UUID                             | Name               | Status |
++----------------------------------+--------------------+--------+
+| bb4a456d6c0948bfae21a6e8c9051d6b | protoc-client-test | Ready  |
++----------------------------------+--------------------+--------+
+```
+
+This means that the zenoh-flow runtime is was loaded and it is ready.
+
+## The transcoding application.
+
+Copy the content of this folder in: `/var/zenoh-flow/flows` and run `pip3 install -r /var/zenoh-flow/flows/requirements.txt`.
+
+
+On a terminal start the publisher side: `cd /var/zenoh-flow/flows && python3 pub-proto.py`
+On a new terminal start the subscriber side: `cd /var/zenoh-flow/flows && python3 pub-cdr.py`
+
+The subscriber will not receive any data as the transcoding is not yet deployed.
+
+On a 3rd terminal instruct zenoh-flow to launch the transcoding flow: `zfctl launch /var/zenoh-flow/flows/dataflow.yml` it will return the instance id.
+
+Now you should see the data being transcoded and received by your subscriber.
+
+Once you are done you can list the current running flow instances: `zfctl list instances` and delete the running one with `zfctl destroy <instance uuid>`.
+
+Once the instance is delete you will see that the subscriber is not going to receive any data.
+
+
+
+
+
+
+
+

transcoding/dataflow.yml

@@ -0,0 +1,35 @@
+flow: Transcoder
+vars:
+ BASE_DIR: "/var/zenoh-flow/flows"
+
+operators:
+  - id : Conversion
+    descriptor: "file://{{ BASE_DIR }}/transcoder.yml"
+sources:
+  - id : ZenohSrc
+    configuration:
+      key-expressions:
+        proto: data/proto
+    descriptor: "builtin://zenoh"
+
+sinks:
+  - id : ZenohSink
+    configuration:
+      key-expressions:
+        cdr: data/cdr
+    descriptor: "builtin://zenoh"
+
+links:
+- from:
+    node : ZenohSrc
+    output : proto
+  to:
+    node : Conversion
+    input : in
+
+- from:
+    node : Conversion
+    output : out
+  to:
+    node : ZenohSink
+    input : cdr

transcoding/message.proto

@@ -0,0 +1,6 @@
+syntax = "proto3";
+
+message MyMsg {
+    uint64 u_value = 1;
+    string s_value = 2;
+}

transcoding/pub-proto.py

@@ -0,0 +1,89 @@
+#
+# Copyright (c) 2022 ZettaScale Technology
+#
+# This program and the accompanying materials are made available under the
+# terms of the Eclipse Public License 2.0 which is available at
+# http://www.eclipse.org/legal/epl-2.0, or the Apache License, Version 2.0
+# which is available at https://www.apache.org/licenses/LICENSE-2.0.
+#
+# SPDX-License-Identifier: EPL-2.0 OR Apache-2.0
+#
+# Contributors:
+#   ZettaScale Zenoh Team, <zenoh@zettascale.tech>
+#
+
+import sys
+import time
+import argparse
+import itertools
+import json
+import zenoh
+from zenoh import config
+from message_pb2 import MyMsg
+
+# --- Command line argument parsing --- --- --- --- --- ---
+parser = argparse.ArgumentParser(
+    prog='z_pub',
+    description='zenoh pub example')
+parser.add_argument('--mode', '-m', dest='mode',
+                    choices=['peer', 'client'],
+                    type=str,
+                    help='The zenoh session mode.')
+parser.add_argument('--connect', '-e', dest='connect',
+                    metavar='ENDPOINT',
+                    action='append',
+                    type=str,
+                    help='Endpoints to connect to.')
+parser.add_argument('--listen', '-l', dest='listen',
+                    metavar='ENDPOINT',
+                    action='append',
+                    type=str,
+                    help='Endpoints to listen on.')
+parser.add_argument('--key', '-k', dest='key',
+                    default='data/proto',
+                    type=str,
+                    help='The key expression to publish onto.')
+parser.add_argument('--value', '-v', dest='value',
+                    default='Pub from Python!',
+                    type=str,
+                    help='The value to publish.')
+parser.add_argument("--iter", dest="iter", type=int,
+                    help="How many puts to perform")
+parser.add_argument('--config', '-c', dest='config',
+                    metavar='FILE',
+                    type=str,
+                    help='A configuration file.')
+
+args = parser.parse_args()
+conf = zenoh.Config.from_file(args.config) if args.config is not None else zenoh.Config()
+if args.mode is not None:
+    conf.insert_json5(zenoh.config.MODE_KEY, json.dumps(args.mode))
+if args.connect is not None:
+    conf.insert_json5(zenoh.config.CONNECT_KEY, json.dumps(args.connect))
+if args.listen is not None:
+    conf.insert_json5(zenoh.config.LISTEN_KEY, json.dumps(args.listen))
+key = args.key
+value = args.value
+
+# initiate logging
+zenoh.init_logger()
+
+print("Opening session...")
+session = zenoh.open(conf)
+
+print(f"Declaring Publisher on '{key}'...")
+pub = session.declare_publisher(key)
+
+for idx in itertools.count() if args.iter is None else range(args.iter):
+    time.sleep(1)
+
+    msg = MyMsg(
+        u_value = idx,
+        s_value = value
+    )
+
+    print(f"Putting Data ('{key}': '{msg}')...")
+    pub.put(msg.SerializeToString())
+
+pub.undeclare()
+session.close()

transcoding/requirements.txt

@@ -0,0 +1,3 @@
+grpcio-tools==1.54.2 
+pycdr2==1.0.0
+eclipse-zenoh==0.7.2rc0