Downloaded 15 times
![Value types and encodings
zenoh supports different value types.
Each has an encoding described by its mime-type:
from zenoh import Zenoh
import json
z = Zenoh({})
workspace = z.workspace()
# - String
workspace.put('/demo/example/String', 'Hello World!')
# - Integer
workspace.put('/demo/example/Integer', 3)
# - Float
workspace.put('/demo/example/Float', 3.14)
# - Properties (as a Dictionary with str only)
workspace.put('/demo/example/Properties', {'p1': 'v1', 'p2': 'v2'})
# - Json (str format)
workspace.put('/demo/example/Json',
Value.Json(json.dumps(['foo', {'bar': ('baz', None, 1.0, 2)}])))
# - Raw ('application/octet-stream' encoding by default)
workspace.put('/demo/example/Raw', b'x48x69x21')
# - Custom
workspace.put('/demo/example/Custom',
Value.Custom('my_encoding', b'x48x69x21'))](https://image.slidesharecdn.com/2021-210212163031/85/Zenoh-Tutorial-14-320.jpg)
Uploaded byAngelo Corsaro
Zenoh Tutorial
This document provides an overview of Zenoh, an open-source distributed data-centric middleware. It summarizes Zenoh's key features including pub/sub, storage/query, compute capabilities and how these can be used in peer-to-peer, routed, and geo-distributed communication patterns. It also describes how to install and use Zenoh in Python and Docker, configure routers and backends, and interact with the system using its REST API.
More Related Content
![[Container Plumbing Days 2023] Why was nerdctl made?](https://cdn.slidesharecdn.com/ss_thumbnails/containerplumbing2023whywasnerdctlmade-230323115340-794fba85-thumbnail.jpg?width=640&height=640&fit=bounds)
Zenoh Tutorial
- 1. Zero Overhead Pub/Sub Store/Query Compute Advanced TechnologyOffice Angelo Corsaro, PhD Chief Technology Officer Luca Cominardi, PhD Senior Technologist Gabriele Baldoni Technologist Julien Enoch Senior Technologist Olivier Hecart Senior Technologist
- 2.
- 3. in Python Requires Python3.6 minimum. Latest version (stable): • Available on pypi.org (https://pypi.org/project/eclipse-zenoh) • Binary wheels for x86_64, i686 and aarch64 • For other platforms: source distribution requiring Rust toolchain (https://www.rust-lang.org/tools/install) pip install eclipse-zenoh Version in development (master): • https://github.com/eclipse-zenoh/zenoh-python • Requires Rust toolchain (https://www.rust-lang.org/tools/install) pip install https://github.com/eclipse-zenoh/zenoh-python/zipball/master Code examples: • https://github.com/eclipse-zenoh/zenoh-python/tree/master/examples/zenoh
- 4. router - inDocker Latest version (stable): docker pull eclipse/zenoh:latest Version in development (master): docker pull eclipse/zenoh:master Usage: docker run --init eclipse/zenoh --help docker run --init -p 7447:7447/tcp -p 7447:7447/udp -p 8000:8000/tcp eclipse/zenoh
- 5. router - native Latestversion (stable): • https://download.eclipse.org/zenoh/zenoh/latest • Files: eclipse-zenoh-<version>-<platform>.tgz (or .zip) Version in development (master): • https://download.eclipse.org/zenoh/zenoh/master • Files: eclipse-zenoh-<version>-<platform>.tgz (or .zip) zenohd --help RUST_LOG=info zenohd Usage:
- 6.
- 7. Peer-to-peer Peer Peer Peer Peer Peer • Multicast discovery •Unicast “neighbour to neighbour” discovery • Unicast “reference point” discovery from zenoh import Zenoh z = Zenoh({"mode": "peer"}) Clique Peer Peer Peer Peer Peer Available soon !!! Mesh Peer init in Python:
- 8. Routed communication Client Client Client Client Router from zenohimport Zenoh z = Zenoh({ "mode": "client", "peer": "tcp/127.0.0.1:7447" }) Client init in Python: zenohd Single router startup:
- 9.
- 10. Routers network Clique Mesh Availablesoon !!! Router Router Router Router Router Router Router Router Router Router zenohd -e tcp/<host1>:7447 -e tcp/<host2>:7447 ... Connected router startup:
- 11. Full picture Peer Peer Peer Peer Peer Peer Peer Peer Peer PeerClient Client Client Router Router Router
- 12.
- 13. pub/sub in Python Publicationsare made via the put() operation: • See https://github.com/eclipse-zenoh/zenoh-python/blob/master/examples/zenoh/z_put.py from zenoh import Zenoh z = Zenoh({}) workspace = z.workspace() workspace.put("/demo/example/hi", "Hello World!") Subscriptions are made via the subscribe() operation: • See https://github.com/eclipse-zenoh/zenoh-python/blob/master/examples/zenoh/z_sub.py from zenoh import Zenoh, ChangeKind def listener(change): print("{} : {} (encoding: {} , timestamp: {})".format(change.path, "DELETED" if change.kind == ChangeKind.DELETE else change.value.get_content(), "none" if change.kind == ChangeKind.DELETE else change.value.encoding_descr(), change.timestamp)) z = Zenoh({}) workspace = z.workspace() workspace.subscribe("/demo/example/**", listener)
- 14. Value types andencodings zenoh supports different value types. Each has an encoding described by its mime-type: from zenoh import Zenoh import json z = Zenoh({}) workspace = z.workspace() # - String workspace.put('/demo/example/String', 'Hello World!') # - Integer workspace.put('/demo/example/Integer', 3) # - Float workspace.put('/demo/example/Float', 3.14) # - Properties (as a Dictionary with str only) workspace.put('/demo/example/Properties', {'p1': 'v1', 'p2': 'v2'}) # - Json (str format) workspace.put('/demo/example/Json', Value.Json(json.dumps(['foo', {'bar': ('baz', None, 1.0, 2)}]))) # - Raw ('application/octet-stream' encoding by default) workspace.put('/demo/example/Raw', b'x48x69x21') # - Custom workspace.put('/demo/example/Custom', Value.Custom('my_encoding', b'x48x69x21'))
- 15.
- 16. Storages Peer Peer Peer Peer Peer Client Client Client Router Router Router zenohd --mem-storage '/a/b/**' --mem-storage'/x/y/**' ... Router with in-memory storages: • Deployed in router • Store publications matching its selector • Replies to queries /a/b/** /x/y/** put(/x/y/1) put(/a/b/2) get(a/b/*) g e t ( / x / y / * )
- 17. pub/store/query in Python Deletionsfrom storage are made via the delete() operation: • See https://github.com/eclipse-zenoh/zenoh-python/blob/master/examples/zenoh/z_delete.py from zenoh import Zenoh z = Zenoh({}) workspace = z.workspace() workspace.delete("/demo/example/hi") Publications are made via the put() operation (seen previously). Queries are made via the get() operation: • See https://github.com/eclipse-zenoh/zenoh-python/blob/master/examples/zenoh/z_get.py from zenoh import Zenoh z = Zenoh({}) workspace = z.workspace() for data in workspace.get("/demo/example/**"): print("{} : {} (encoding: {} , timestamp: {})".format( data.path, data.value.get_content(), data.value.encoding_descr(), data.timestamp))
- 18.
- 19. Compute Peer Peer Peer Peer Peer Client Client Client Router Router Router • Evalfunction declared by zenoh applications that compute a value on demand • Called by queries register_eval(/x/y/z) get(a/b/*) g e t ( / x / y / * ) register_eval(/a/b/c)
- 20. Compute/query in Python Queriesare made via the get() operation (seen previously). Compute are declared via the register_eval() operation: • See https://github.com/eclipse-zenoh/zenoh-python/blob/master/examples/zenoh/z_eval.py import datetime from zenoh import Zenoh def eval_callback(get_request): get_request.reply("/demo/example/eval", "It's {}".format(datetime.datetime.now().time())) z = Zenoh({}) workspace = z.workspace() workspace.register_eval("/demo/example/eval", eval_callback)
- 21.
- 22. REST API Implemented asa plugin. Default port: 8080. The zenoh put/get/delete operations map to the PUT/GET/DELETE HTTP methods. Example using the curl command: # Put a string value in /demo/example/test curl -X PUT -d 'Hello World!' http://localhost:8000/demo/example/test # Put a JSON value in /demo/example/json curl -X PUT -H "Content-Type: application/json" -d '{"value": "Hello World!"}' http://localhost:8000/demo/example/test # Put a Properties value in /demo/example/props curl -X PUT -H 'content-type:application/properties' -d 'k1=v1;k2=v2' http://localhost:8000/demo/example/props # Get the keys/values matching /demo/** curl http://localhost:8000/demo/** # Get the keys/values matching /demo/example/*eval (i.e. the zenoh eval examples) # with property name=Bob curl http://localhost:8000/demo/example/*eval?(name=Bob) # Delete key/value /demo/example/test curl -X DELETE http://localhost:8000/demo/example/test
- 23.
- 24. Backends A zenoh backendis: • a library, loaded on demand by the zenoh router (name: libzbackend_<id>.so) • a factory for zenoh storages • leveraging a speci fi c technology to implement storages Existing backends: • In-memory: built-in in zenoh router • File system: • https://github.com/eclipse-zenoh/zenoh-backend- fi lesystem • RocksDB: • https://github.com/eclipse-zenoh/zenoh-backend-rocksdb • In fl uxDB: • https://github.com/eclipse-zenoh/zenoh-backend-in fl uxdb
- 25. Admin space zenoh adminspace: •A zenoh key/value space with under /@/** •Addressable via zenoh APIs using put/get/delete operations •Each router addressable via its ID, or the "local" keyword for the router an API is connected to /@/router/1a2b3c.../plugin/storages /backend /memory /rocksdb /<beid> /storage /storage /s2 /s1 ... ... /storage /db2 /db1 ... # Get local router's info curl http://localhost:8000/@/router/local # Get all routers' of the system curl http://localhost:8000/@/router/* # Get local router's storages info curl http://localhost:8000/@/router/local/**/storages/** Examples using the REST API:
- 26. Backends/storages management Examples usingthe REST API: # Add a memory storage curl -X PUT -H 'content-type:application/properties' -d 'path_expr=/demo/test/**' http://localhost:8000/@/router/local/plugin/storages/backend/memory/storage/my-test # Add a FileSystem backend (assuming libzbackend_fs.so is available) curl -X PUT -H 'content-type:application/properties' http://localhost:8000/@/router/local/plugin/storages/backend/fs # Add a FileSystem storage curl -X PUT -H 'content-type:application/properties' -d 'path_expr=/demo/example/**;path_prefix=/demo/example;dir=test' http://localhost:8000/@/router/local/plugin/storages/backend/fs/storage/my-test # Add an InfluxDB backend (assuming libzbackend_influxdb.so is available and InfluxDB running at http://localhost:8086) curl -X PUT -H 'content-type:application/properties' -d 'url=http://localhost:8086' http://localhost:8000/@/router/local/plugin/storages/backend/influxdb # Add an InfluxDB storage using the database named "zenoh-example" curl -X PUT -H 'content-type:application/properties' -d 'path_expr=/demo/example/**;db=zenoh-example' http://localhost:8000/@/router/local/plugin/storages/backend/influxdb/storage/my-test
- 27.
- 28. Plugins A zenoh pluginis • a library, loaded at start-up by the zenoh router (name: libzplugin_<id>.so) • similar to zenoh application using the zenoh APIs (in RUST) • using the router's runtime => no transport overhead Existing plugins: • REST plugin (packaged with zenoh deliverable) • Storages plugin (packaged with zenoh deliverable) • WebServer plugin: • https://github.com/eclipse-zenoh/zenoh-plugin-webserver • DDS plugin: • https://github.com/eclipse-zenoh/zenoh-plugin-dds
- 29.
- 30. us-west.zenoh.io /demo/us-west/** us-east.zenoh.io /demo/us-east/** eu.zenoh.io /demo/eu/** ap.zenoh.io /demo/ap/** Example: • Put data:curl -X PUT -d 'Hello World!' http://us-west.zenoh.io:8000/demo/eu/test • Get data: curl http://ap.zenoh.io:8000/demo/*/test
- 31. us-west.zenoh.io /demo/us-west/** us-east.zenoh.io /demo/us-east/** eu.zenoh.io /demo/eu/** ap.zenoh.io /demo/ap/** Example: • Get timeseries: curl http://us-west.zenoh.io:8000/demo/influxdb/**?(stoptime=now()) • Browse /public/**: http://eu.zenoh.io:8080/public File system storage /public/** File system storage /public/** InfluxDB storage /demo/influxdb/** RocksDB storage /demo/rocksdb/** After addition of backends/storages:
- 32.
- 33.