README.md

Zenoh Python Examples

Get Started

python3 <example.py>

Each example accepts the -h or --help option that provides a description of its arguments and their default values.

If you run the tests against the zenoh router running in a Docker container, you need to add the -e tcp/localhost:7447 option to your examples. That's because Docker doesn't support UDP multicast transport, and therefore the zenoh scouting and discrovery mechanism cannot work with.

Examples description

z_scout

Scouts for zenoh peers and routers available on the network.

Typical usage:

   python3 z_scout.py

z_info

Gets information about the Zenoh session.

Typical usage:

   python3 z_info.py

z_put

Puts a path/payload into Zenoh. The path/payload will be received by all matching subscribers, for instance the z_sub and z_storage examples.

Typical usage:

   python3 z_put.py

or

   python3 z_put.py -k demo/example/test -v 'Hello World'

z_pub

Declares a resource with a path and a publisher on this resource. Then puts a payload using the numerical resource id. The path/payload will be received by all matching subscribers, for instance the z_sub and z_storage examples.

Typical usage:

   python3 z_pub.py

or

   python3 z_pub.py -k demo/example/test -v 'Hello World'

z_sub

Creates a subscriber with a key expression. The subscriber will be notified of each put made on any key expression matching the subscriber's key expression, and will print this notification.

Typical usage:

   python3 z_sub.py

or

   python3 z_sub.py -k 'demo/**'

z_get

Sends a query message for a selector. The queryables with a matching path or selector (for instance z_queryable and z_storage) will receive this query and reply with paths/payloads that will be received by the query callback.

Typical usage:

   python3 z_get.py

or

   python3 z_get.py -s 'demo/**'

z_querier

Continuously sends query messages for a selector. The queryables with a matching path or selector (for instance z_queryable and z_storage) will receive these queries and reply with paths/payloads that will be received by the querier's query callback.

Typical usage:

   python3 z_querier.py

or

   python3 z_get.py -s 'demo/**'

z_queryable

Creates a queryable function with a key expression. This queryable function will be triggered by each call to a get operation on zenoh with a selector that matches the key expression, and will return a payload to the querier.

Typical usage:

   python3 z_queryable.py

or

   python3 z_queryable.py -k demo/example/queryable -v 'This is the result'

z_storage

Trivial implementation of a storage in memory. This examples creates a subscriber and a queryable on the same key expression. The subscriber callback will store the received key/values in an hashmap. The queryable callback will answer to queries with the key/values stored in the hashmap and that match the queried selector.

Typical usage:

   python3 z_storage.py

or

   python3 z_storage.py -k 'demo/**'

z_pub_thr & z_sub_thr

Pub/Sub throughput test. This example allows to perform throughput measurements between a pubisher performing put operations and a subscriber receiving notifications of those puts.

Typical Subscriber usage:

   python3 z_sub_thr.py

Typical Publisher usage:

   python3 z_pub_thr.py 1024