Zenoh API Reference¶

[Zenoh](https://zenoh.io) /zeno/ is a stack that unifies data in motion, data at rest and computations. It elegantly blends traditional pub/sub with geo distributed storage, queries and computations, while retaining a level of time and space efficiency that is well beyond any of the mainstream stacks.

Before delving into the examples, we need to introduce few Zenoh concepts. First off, in Zenoh you will deal with Resources, where a resource is made up of a key and a value. The other concept you’ll have to familiarize yourself with are key expressions, such as robot/sensor/temp, robot/sensor/*, robot/**, etc. As you can gather, the above key expression denotes set of keys, while the * and ** are wildcards representing respectively (1) a single chunk (non-empty sequence of characters that doesn’t contain /), and (2) any amount of chunks (including 0).

Below are some examples that highlight these key concepts and show how easy it is to get started with.

Quick start examples:¶

Publish a key/value pair onto Zenoh¶

>>> import zenoh
>>> z = zenoh.open()
>>> z.put('/demo/example/hello', 'Hello World!')

Get keys/values from zenoh¶

>>> import zenoh
>>> z = zenoh.open()
>>> for response in z.get('/demo/example/**', zenoh.Queue()):
>>>     response = response.ok
>>>     print(f"{response.key_expr} => {response.payload.decode('utf-8')}")

module zenoh¶

zenoh.init_logger()¶

Initialize the logger used by the Rust implementation of this API.

Once initialized, you can configure the logs displayed by the API using the RUST_LOG environment variable. For instance, start python with the debug logs available:

$ RUST_LOG=debug python

More details on the RUST_LOG configuration on https://docs.rs/env_logger/latest/env_logger

zenoh.open(*args, **kwargs)¶

Open a zenoh-net Session.

Parameters:	config (Config) – The configuration of the zenoh-net session
Return type:	Session
Example:

>>> import zenoh
>>> s = zenoh.open(zenoh.Config())

zenoh.scout(handler: Union[zenoh.closures.IHandler[zenoh.value.Hello, typing.Any, typing.Any][zenoh.value.Hello, Any, Any], zenoh.closures.IClosure[zenoh.value.Hello, typing.Any][zenoh.value.Hello, Any], Tuple[zenoh.closures.IClosure, Any], Tuple[Callable[[zenoh.value.Hello], Any], Callable[[], None], Any], Tuple[Callable[[zenoh.value.Hello], Any], Callable[[], None]], Callable[[zenoh.value.Hello], Any]] = None, what: str = None, config: zenoh.config.Config = None, timeout=None)¶

Scout for routers and/or peers.

This spawns a task that periodically sends scout messages for a specified duration and returns a list of received Hello messages.

Parameters:	what – The kind of zenoh process to scout for config – The configuration to use for scouting timeout – the duration of scout (in seconds) handler –
Return type:	list of `Hello`
Example:

>>> import zenoh
>>> for hello in zenoh.scout(what = "peer|router", timeout=1.0).receiver():
...     print(hello)

Hello¶

class zenoh.Hello¶

Represents a single Zenoh node discovered through scouting.

locators¶: The locators through which this node may be adressed.

whatami¶: The node’s type, returning either None, ‘peer’, ‘router’, or ‘client’.

zid¶: The node’s Zenoh UUID.

Config¶

class zenoh.Config¶

static from_file(filename: str)¶: Reads the configuration from a file. The file’s extension must be json, json5 or yaml.

static from_json5(json: str)¶

Reads the configuration from a JSON5 string.

JSON5 is a superset of JSON, so any JSON string is a valid input for this function.

static from_obj(obj)¶: Reads the configuration from obj as if it was a JSON file.

get_json(path: str) → str¶: Returns the part of the configuration at path, in a JSON-serialized form.

insert_json5(path: str, value: str) → str¶: Inserts the provided value (read from JSON) at the given path in the configuration.

Session¶

class zenoh.Session¶

A Zenoh Session, the core interraction point with a Zenoh network.

Note that most applications will only need a single instance of Session. You should _never_ construct one session per publisher/subscriber, as this will significantly increase the size of your Zenoh network, while preventing potential locality-based optimizations.

close()¶

Attempts to close the Session.

The session will only be closed if all publishers, subscribers and queryables based on it have been undeclared, and there are no more python references to it.

config() → zenoh.config.Config¶

Returns a configuration object that can be used to alter the session’s configuration at runtime.

Note that in Python specifically, the config you passed to the session becomes the result of this function if you passed one, letting you keep using it.

declare_keyexpr(keyexpr: Union[KeyExpr, _KeyExpr, str]) → zenoh.keyexpr.KeyExpr¶

Informs Zenoh that you intend to use the provided Key Expression repeatedly.

This function returns an optimized representation of the passed keyexpr.

It is generally not needed to declare key expressions, as declaring a subscriber, a queryable, or a publisher will also inform Zenoh of your intent to use their key expressions repeatedly.

declare_publisher(keyexpr: Union[KeyExpr, _KeyExpr, str], priority: zenoh.enums.Priority = None, congestion_control: zenoh.enums.CongestionControl = None)¶

Declares a publisher, which may be used to send values repeatedly onto a same key expression.

Written resources that match the given key will only be sent on the network if matching subscribers exist in the system.

Parameters:	keyexpr – The key expression to publish to priority – The priority to use when routing the published data congestion_control – The congestion control to use when routing the published data
Return type:	Publisher
Examples:

>>> import zenoh
>>> s = zenoh.open({})
>>> pub = s.declare_publisher('key/expression')
>>> pub.put('value')

declare_pull_subscriber(keyexpr: Union[KeyExpr, _KeyExpr, str], handler: Union[zenoh.closures.IHandler[zenoh.value.Sample, typing.Any, typing.Any][zenoh.value.Sample, Any, Any], zenoh.closures.IClosure[zenoh.value.Sample, typing.Any][zenoh.value.Sample, Any], Tuple[zenoh.closures.IClosure, Any], Tuple[Callable[[zenoh.value.Sample], Any], Callable[[], None], Any], Tuple[Callable[[zenoh.value.Sample], Any], Callable[[], None]], Callable[[zenoh.value.Sample], Any]], reliability: zenoh.enums.Reliability = None) → zenoh.session.PullSubscriber¶

Declares a pull-mode subscriber, which will receive a single published sample with a key expression intersecting keyexpr any time its pull method is called.

These samples are passed to the handler’s closure as instances of the Sample class. The handler can typically be a queue or a callback. The handler’s receiver is returned as the receiver field of the returned PullSubscriber.

Parameters:	keyexpr – The key expression to subscribe to handler – reliability – the reliability to use when routing the subscribed samples
Return type:	PullSubscriber
Examples:

>>> import zenoh
>>> s = zenoh.open({})
>>> sub = s.declare_pull_subscriber('key/expression', lambda sample:
...     print(f"Received '{sample.key_expr}': '{sample.payload.decode('utf-8')}'"))
...
>>> sub.pull()

declare_queryable(keyexpr: Union[KeyExpr, _KeyExpr, str], handler: Union[zenoh.closures.IHandler[zenoh.queryable.Query, typing.Any, typing.Any][zenoh.queryable.Query, Any, Any], zenoh.closures.IClosure[zenoh.queryable.Query, typing.Any][zenoh.queryable.Query, Any], Tuple[zenoh.closures.IClosure, Any], Tuple[Callable[[zenoh.queryable.Query], Any], Callable[[], None], Any], Tuple[Callable[[zenoh.queryable.Query], Any], Callable[[], None]], Callable[[zenoh.queryable.Query], Any]], complete: bool = None)¶

Declares a queryable, which will receive queries intersecting with keyexpr.

These queries are passed to the handler as instances of the Query class. The handler can typically be a queue or a callback. The handler’s receiver is returned as the receiver field of the returned Queryable. The replies can be sent back by calling the reply`function of the `Query.

Examples:

Using a callback:

>>> import zenoh
>>> s = zenoh.open({})
>>> qabl = s.declare_queryable('key/expression', lambda query:
...     query.reply(zenoh.Sample('key/expression', 'value')))

Using a queue:

>>> import zenoh
>>> s = zenoh.open({})
>>> qabl = s.declare_queryable('key/expression', zenoh.Queue())
>>> while True:
...     query = qabl.receiver.get()
...     query.reply(zenoh.Sample('key/expression', 'value'))
...     del query

IMPORTANT: due to how RAII and Python work, you MUST bind this function’s return value to a variable in order for it to function as expected. This is because as soon as a value is no longer referenced in Python, that value’s destructor will run, which will undeclare your queryable, stopping it immediately.

declare_subscriber(keyexpr: Union[KeyExpr, _KeyExpr, str], handler: Union[zenoh.closures.IHandler[zenoh.value.Sample, typing.Any, typing.Any][zenoh.value.Sample, Any, Any], zenoh.closures.IClosure[zenoh.value.Sample, typing.Any][zenoh.value.Sample, Any], Tuple[zenoh.closures.IClosure, Any], Tuple[Callable[[zenoh.value.Sample], Any], Callable[[], None], Any], Tuple[Callable[[zenoh.value.Sample], Any], Callable[[], None]], Callable[[zenoh.value.Sample], Any]], reliability: zenoh.enums.Reliability = None) → zenoh.session.Subscriber¶

Declares a subscriber, which will receive any published sample with a key expression intersecting keyexpr.

These samples are provided to the handler as instances of the Sample class. The handler can typically be a queue or a callback. The handler’s receiver is returned as the receiver field of the returned Subscriber.

Parameters:	keyexpr – The key expression to subscribe to handler – reliability – the reliability to use when routing the subscribed samples
Return type:	Subscriber
Examples:

Using a callback:

>>> import zenoh
>>> s = zenoh.open({})
>>> sub = s.declare_subscriber('key/expression', lambda sample:
...     print(f"Received '{sample.key_expr}': '{sample.payload.decode('utf-8')}'")

Using a queue:

>>> import zenoh
>>> s = zenoh.open({})
>>> sub = s.declare_subscriber('key/expression', zenoh.Queue())
>>> for sample in sub.receiver:
>>>     print(f"{sample.key_expr}: {sample.payload.decode('utf-8')}")

IMPORTANT: due to how RAII and Python work, you MUST bind this function’s return value to a variable in order for it to function as expected. This is because as soon as a value is no longer referenced in Python, that value’s destructor will run, which will undeclare your subscriber, deactivating the subscription immediately.

delete(keyexpr: Union[KeyExpr, _KeyExpr, str], priority: zenoh.enums.Priority = None, congestion_control: zenoh.enums.CongestionControl = None)¶

Deletes the values associated with the keys included in keyexpr.

This uses the same mechanisms as session.put, and will be received by subscribers. This operation is especially useful with storages.

Parameters:	keyexpr – The key expression to publish priority – The priority to use when routing the delete congestion_control – The congestion control to use when routing the delete
Examples:

>>> import zenoh
>>> s = zenoh.open({})
>>> s.delete('key/expression')

get(selector: Union[Selector, _Selector, KeyExpr, _KeyExpr, str], handler: Union[zenoh.closures.IHandler[zenoh.value.Reply, typing.Any, ~Receiver][zenoh.value.Reply, Any, Receiver], zenoh.closures.IClosure[zenoh.value.Reply, typing.Any][zenoh.value.Reply, Any], Tuple[zenoh.closures.IClosure, Receiver], Tuple[Callable[[zenoh.value.Reply], Any], Callable[[], None], Receiver], Tuple[Callable[[zenoh.value.Reply], Any], Callable[[], None]], Callable[[zenoh.value.Reply], Any]], consolidation: zenoh.enums.QueryConsolidation = None, target: zenoh.enums.QueryTarget = None, value: Union[zenoh.value.IValue, bytes, str, int, float, object] = None) → Receiver¶

Emits a query, which queryables with intersecting selectors will be able to reply to.

The replies are provided to the given handler as instances of the Reply class. The handler can typically be a queue, a single callback or a pair of callbacks. The handler’s receiver is returned by the get function.

Parameters:	selector – The selection of keys to query handler – consolidation – The consolidation to apply to replies target – The queryables that should be target to this query value – An optional value to attach to this query
Returns:	The receiver of the handler
Return type:	Receiver
Examples:

Using a queue:

>>> import zenoh
>>> s = zenoh.open({})
>>> for reply in s.get('key/expression', zenoh.Queue()):
...     try:
...         print(f"Received '{reply.ok.key_expr}': '{reply.ok.payload.decode('utf-8')}'")
...     except:
...         print(f"Received ERROR: '{reply.err.payload.decode('utf-8')}'")

Using a single callback:

>>> s.get('key/expression', lambda reply:
...     print(f"Received '{reply.ok.key_expr}': '{reply.ok.payload.decode('utf-8')}'")
...     if reply.ok is not None else print(f"Received ERROR: '{reply.err.payload.decode('utf-8')}'"))

Using a reply callback and a termination callback:

>>> s.get('key/expression', (
...     lambda reply:
...         print(f"Received '{reply.ok.key_expr}': '{reply.ok.payload.decode('utf-8')}'")
...         if reply.ok is not None else print(f"Received ERROR: '{reply.err.payload.decode('utf-8')}'"),
...     lambda:
...         print("No more replies")))

info()¶: Returns an accessor for informations about this Session

put(keyexpr: Union[KeyExpr, _KeyExpr, str], value: Union[zenoh.value.IValue, bytes, str, int, float, object], encoding=None, priority: zenoh.enums.Priority = None, congestion_control: zenoh.enums.CongestionControl = None, sample_kind: zenoh.enums.SampleKind = None)¶

Sends a value over Zenoh.

Subscribers on an expression that intersect with keyexpr will receive the sample. Storages will store the value if keyexpr is non-wild, or update the values for all known keys that are included in keyexpr if it is wild.

Parameters:	keyexpr – The key expression to publish value – The value to send priority – The priority to use when routing the published data congestion_control – The congestion control to use when routing the published data sample_kind – The kind of sample to send
Examples:

>>> import zenoh
>>> s = zenoh.open({})
>>> s.put('key/expression', 'value')

Info¶

class zenoh.Info(session: _Session)¶

peers_zid() → List[zenoh.value.ZenohId]¶: Returns the neighbooring peers’ identifiers

routers_zid() → List[zenoh.value.ZenohId]¶: Returns the neighbooring routers’ identifiers

zid() → zenoh.value.ZenohId¶: Returns this Zenoh Session’s identifier

KeyExpr¶

class zenoh.KeyExpr¶

Zenoh’s address space is designed around keys which serve as the names of ressources.

Keys are slash-separated lists of non-empty UTF8 strings. They may not contain the following characters: $*#?.

Zenoh’s operations are executed on key expressions, a small language that allows the definition of sets of keys via the use of wildcards:

* is the single-chunk wildcard, and will match any chunk: a/*/c will match a/b/c, a/hello/c, etc…

** is the 0 or more chunks wildcard: a/**/c matches a/c, a/b/c, a/b/hello/c, etc…

$* is the subchunk wildcard, it will match any amount of non-/ characters: a/b$* matches a/b, a/because, a/blue… but not a/c nor a/blue/c

To allow for better performance and gain the property that two key expressions define the same set if and only if they are the same string, the rules of canon form are mandatory for a key expression to be propagated by a Zenoh network:

**/** may not exist, as it could always be replaced by the shorter **,

**/* may not exist, and must be written as its equivalent */** instead,

$* may not exist alone in a chunk, as it must be written * instead.

The KeyExpr.autocanonize constructor exists to correct eventual infrigements of the canonization rules.

A KeyExpr is a string that has been validated to be a valid Key Expression.

static autocanonize(expr: str) → zenoh.keyexpr.KeyExpr¶

This alternative constructor for key expressions will attempt to canonize the passed expression before checking if it is valid.

Raises a zenoh.ZError exception if expr is not a valid key expression.

includes(other: Union[KeyExpr, _KeyExpr, str]) → bool¶: This method returns True if all of the keys defined by other also belong to the set defined by self.

intersects(other: Union[KeyExpr, _KeyExpr, str]) → bool¶: This method returns True if there exists at least one key that belongs to both sets defined by self and other.

undeclare(session: Session)¶: Undeclares a key expression previously declared on the session.

Sample¶

class zenoh.Sample¶

A KeyExpr-Value pair, annotated with the kind (PUT or DELETE) of publication used to emit it and a timestamp.

encoding¶: A shortcut to self.value.encoding

key_expr¶: The sample’s key expression

kind¶: The sample’s kind

payload¶: A shortcut to self.value.payload

timestamp¶: The sample’s timestamp. May be None.

value¶: The sample’s value

SampleKind¶

class zenoh.SampleKind¶

Similar to an HTTP METHOD: only PUT and DELETE are currently supported.

static DELETE() → zenoh.enums.SampleKind¶

static PUT() → zenoh.enums.SampleKind¶

Value¶

class zenoh.Value¶

A Value is a pair of a binary payload, and a mime-type-like encoding string.

When constructed with encoding==None, the encoding will be selected depending on the payload’s type.

static autoencode(value: Union[zenoh.value.IValue, bytes, str, int, float, object]) → zenoh.value.Value¶: Automatically encodes the value based on its type

Encoding¶

class zenoh.Encoding¶

static APP_CUSTOM() → zenoh.enums.Encoding¶

static APP_FLOAT() → zenoh.enums.Encoding¶

static APP_INTEGER() → zenoh.enums.Encoding¶

static APP_JSON() → zenoh.enums.Encoding¶

static APP_OCTET_STREAM() → zenoh.enums.Encoding¶

static APP_PROPERTIES() → zenoh.enums.Encoding¶

static APP_SQL() → zenoh.enums.Encoding¶

static APP_XHTML_XML() → zenoh.enums.Encoding¶

static APP_XML() → zenoh.enums.Encoding¶

static APP_X_WWW_FORM_URLENCODED() → zenoh.enums.Encoding¶

static EMPTY() → zenoh.enums.Encoding¶

static IMAGE_GIF() → zenoh.enums.Encoding¶

static IMAGE_JPEG() → zenoh.enums.Encoding¶

static IMAGE_PNG() → zenoh.enums.Encoding¶

static TEXT_CSS() → zenoh.enums.Encoding¶

static TEXT_CSV() → zenoh.enums.Encoding¶

static TEXT_HTML() → zenoh.enums.Encoding¶

static TEXT_JAVASCRIPT() → zenoh.enums.Encoding¶

static TEXT_JSON() → zenoh.enums.Encoding¶

static TEXT_PLAIN() → zenoh.enums.Encoding¶

static TEXT_XML() → zenoh.enums.Encoding¶

append(s: str)¶

static from_str(s: str) → zenoh.enums.Encoding¶

Publisher¶

class zenoh.Publisher(p: _Publisher)¶

Use Publisher (constructed with Session.declare_publisher) when you want to send values often for the same key expression, as declaring them informs Zenoh that this is you intent, and optimizations will be set up to do so.

delete()¶: An optimised version of session.delete(self.key_expr)

key_expr¶: This Publisher’s key expression

put(value: Union[zenoh.value.IValue, bytes, str, int, float, object], encoding: zenoh.enums.Encoding = None)¶: An optimised version of session.put(self.key_expr, value, encoding=encoding)

undeclare()¶: Stops the publisher.

CongestionControl¶

class zenoh.CongestionControl¶

Defines the network’s behaviour regarding a message when heavily congested.

static BLOCK() → zenoh.enums.CongestionControl¶: Prevents the message from being dropped at all cost. In the face of heavy congestion on a part of the network, this could result in your publisher node blocking.

static DROP() → zenoh.enums.CongestionControl¶: Allows the message to be dropped if all buffers are full.

Priority¶

class zenoh.Priority¶

The priority of a sending operation.

They are ordered à la Linux priority: Priority.REAL_TIME() < Priority.INTERACTIVE_HIGH() < Priority.INTERACTIVE_LOW() < Priority.DATA() < Priority.BACKGROUND()

static BACKGROUND() → zenoh.enums.Priority¶

static DATA() → zenoh.enums.Priority¶

static DATA_HIGH() → zenoh.enums.Priority¶

static DATA_LOW() → zenoh.enums.Priority¶

static INTERACTIVE_HIGH() → zenoh.enums.Priority¶

static INTERACTIVE_LOW() → zenoh.enums.Priority¶

static REAL_TIME() → zenoh.enums.Priority¶

Subscriber¶

class zenoh.Subscriber(s: _Subscriber, receiver=None)¶

A handle to a subscription.

Its main purpose is to keep the subscription active as long as it exists.

When constructed through Session.declare_subscriber(session, keyexpr, handler), it exposes handler’s receiver through self.receiver.

undeclare()¶: Undeclares the subscription

PullSubscriber¶

class zenoh.PullSubscriber(s: _PullSubscriber, receiver=None)¶

A handle to a pull subscription.

Its main purpose is to keep the subscription active as long as it exists.

When constructed through Session.declare_pull_subscriber(session, keyexpr, handler), it exposes handler’s receiver through self.receiver.

Calling self.pull() will prompt the Zenoh network to send a new sample when available.

pull()¶: Prompts the Zenoh network to send a new sample if available. Note that this sample will not be returned by this function, but provided to the handler’s callback.

undeclare()¶: Undeclares the subscription

Reliability¶

class zenoh.Reliability¶

Used by subscribers to inform the network of the reliability it wishes to obtain.

static BEST_EFFORT() → zenoh.enums.CongestionControl¶: Informs the network that dropping some messages is acceptable

static RELIABLE() → zenoh.enums.CongestionControl¶

Informs the network that this subscriber wishes for all publications to reliably reach it.

Note that if a publisher puts a sample with the CongestionControl.DROP() option, this reliability requirement may be infringed to prevent slow readers from blocking the network.

Query¶

class zenoh.Query¶

decode_parameters() → Dict[str, str]¶

Decodes the value selector into a dictionary.

Raises a ZError if duplicate keys are found, as they might otherwise be used for HTTP Parameter Pollution like attacks.

key_expr¶: The query’s targeted key expression

parameters¶: The query’s value selector. If you’d rather not bother with parsing it yourself, use self.decode_parameters() instead.

reply(sample: zenoh.value.Sample)¶: Allows you to reply to a query. You may send any amount of replies to a single query, including 0.

selector¶: The query’s selector as a whole.

value¶: The query’s value.

Selector¶

class zenoh.Selector¶

A selector is the combination of a [Key Expression](crate::prelude::KeyExpr), which defines the set of keys that are relevant to an operation, and a parameters, a set of key-value pairs with a few uses:

specifying arguments to a queryable, allowing the passing of Remote Procedure Call parameters

filtering by value,

filtering by metadata, such as the timestamp of a value,

When in string form, selectors look a lot like a URI, with similar semantics:

the key_expr before the first ? must be a valid key expression.

the parameters after the first ? should be encoded like the query section of a URL:

key-value pairs are separated by &,

the key and value are separated by the first =,

in the absence of =, the value is considered to be the empty string,

both key and value should use percent-encoding to escape characters,

defining a value for the same key twice is considered undefined behavior.

Zenoh intends to standardize the usage of a set of keys. To avoid conflicting with RPC parameters, the Zenoh team has settled on reserving the set of keys that start with non-alphanumeric characters.

This document will summarize the standardized keys for which Zenoh provides helpers to facilitate coherent behavior for some operations.

Queryable implementers are encouraged to prefer these standardized keys when implementing their associated features, and to prefix their own keys to avoid having conflicting keys with other queryables.

Here are the currently standardized keys for Zenoh:

_time: used to express interest in only values dated within a certain time range, values for this key must be readable by the [Zenoh Time DSL](zenoh_util::time_range::TimeRange) for the value to be considered valid.

_filter: TBD Zenoh intends to provide helper tools to allow the value associated with this key to be treated as a predicate that the value should fulfill before being returned. A DSL will be designed by the Zenoh team to express these predicates.

decode_parameters() → Dict[str, str]¶

Decodes the value selector part of the selector.

Raises a ZError if some keys were duplicated: duplicated keys are considered undefined behaviour, but we encourage you to refuse to process incoming messages with duplicated keys, as they might be attempting to use HTTP Parameter Pollution like exploits.

key_expr¶: The key expression part of the selector.

parameters¶: The value selector part of the selector.

set_parameters¶: The value selector part of the selector.

QueryTarget¶

class zenoh.QueryTarget¶

QueryConsolidation¶

class zenoh.QueryConsolidation¶

Reply¶

class zenoh.Reply¶

A reply to a query (Session.get).

A single query can result in multiple replies from multiple queryables.

err¶

The reply’s error value.

Raises a ZError if the self is actually an ok reply.

ok¶

The reply’s inner data sample.

Raises a ZError if the self is actually an err reply.

replier_id¶: The reply’s sender’s id.

Queryable¶

class zenoh.Queryable(inner: _Queryable, receiver)¶

A handle to a queryable.

Its main purpose is to keep the queryable active as long as it exists.

When constructed through Session.declare_queryable(session, keyexpr, handler), it exposes handler’s receiver through self.receiver.

undeclare()¶: Stops the queryable.

ZenohId¶

class zenoh.ZenohId¶: A Zenoh UUID

Timestamp¶

class zenoh.Timestamp¶

A timestamp taken from the Zenoh HLC (Hybrid Logical Clock).

These timestamps are guaranteed to be unique, as each machine annotates its perceived time with a UUID, which is used as the least significant part of the comparison operation.

seconds_since_unix_epoch¶

Returns the number of seconds since the Unix Epoch.

You shouldn’t use this for comparison though, and rely on comparison operators between members of this class.

class zenoh.Queue(bound: int = None)¶

A binding for a Rust multi-producer, single-consumer queue implementation.

When used as a handler, it provides itself as the receiver, and will provide a callback that appends elements to the queue.

Can be bounded by passing a maximum size as bound.

closure¶: The part of the handler that should be passed as a callback to a zenoh function.

get(timeout: float = None)¶

Gets one element from the queue.

Raises a StopIteration exception if the queue was closed before the timeout ran out, this allows using the Queue as an iterator in for-loops. Raises a TimeoutError if the timeout ran out.

get_remaining(timeout: float = None) → List[In]¶

Awaits the closing of the queue, returning the remaining queued values in a list. The values inserted into the queue up until this happens will be available through get.

Raises a TimeoutError if the timeout in seconds provided was exceeded before closing, whose args[0] will contain the elements that were collected before timing out.

put(value)¶

Puts one element on the queue.

Raises a PyBrokenPipeError if the Queue has been closed.

receiver¶: The part of the handler that should be used as the receiver when the handler is channel-like.

class zenoh.ListCollector(timeout=None)¶

A simple collector that aggregates values into a list.

When used as a handler, it provides a callback that appends elements to a list, and provides a function that will await the closing of the callback before returning said list.

closure¶: The part of the handler that should be passed as a callback to a zenoh function.

receiver¶: The part of the handler that should be used as the receiver when the handler is channel-like.

class zenoh.Closure(closure: Union[zenoh.closures.IHandler[~In, ~Out, typing.Any][In, Out, Any], zenoh.closures.IClosure[~In, ~Out][In, Out], Tuple[Callable[[In], Out], Callable[[], None]], Callable[[In], Out]], type_adaptor: Callable[[Any], In] = None, prevent_direct_calls=False)¶

A Closure is a pair of a call function that will be used as a callback, and a drop function that will be called when the closure is destroyed.

call¶: Returns the closure’s call function as a lambda.

drop¶: Returns the closure’s destructor as a lambda.

class zenoh.Handler(input: Union[zenoh.closures.IHandler[~In, ~Out, ~Receiver][In, Out, Receiver], zenoh.closures.IClosure[~In, ~Out][In, Out], Tuple[zenoh.closures.IClosure, Receiver], Tuple[Callable[[In], Out], Callable[[], None], Receiver], Tuple[Callable[[In], Out], Callable[[], None]], Callable[[In], Out]], type_adaptor: Callable[[Any], In] = None, prevent_direct_calls=True)¶

A Handler is a value that may be converted into a callback closure for zenoh to use on one side, while possibly providing a receiver for the data that zenoh would provide through that callback.

Note that the values will be piped onto a Queue before being sent to your handler by another Thread unless either:

input is already an instance of Closure or Handler where input.closure is an instance of Closure
prevent_direct_calls is set to False

closure¶: The part of the handler that should be passed as a callback to a zenoh function.

receiver¶: The part of the handler that should be used as the receiver when the handler is channel-like.

class zenoh.IClosure¶

A Closure is a pair of a call function that will be used as a callback, and a drop function that will be called when the closure is destroyed.

call¶: Returns the closure’s call function as a lambda.

drop¶: Returns the closure’s destructor as a lambda.

class zenoh.IHandler¶

A Handler is a value that may be converted into a callback closure for zenoh to use on one side, while possibly providing a receiver for the data that zenoh would provide through that callback.

closure¶: The part of the handler that should be passed as a callback to a zenoh function.

receiver¶: The part of the handler that should be used as the receiver when the handler is channel-like.

class zenoh.IValue¶

The IValue interface exposes how to recover a value’s payload in a binary-serialized format, as well as that format’s encoding.

encoding¶: The value’s encoding

payload¶: The value itself, as an array of bytes

Zenoh API Reference¶

Quick start examples:¶

Publish a key/value pair onto Zenoh¶

Subscribe to a set of keys with Zenoh¶

Get keys/values from zenoh¶

module zenoh¶

Hello¶

Config¶

Session¶

Info¶

KeyExpr¶

Sample¶

SampleKind¶

Value¶

Encoding¶

Publisher¶

CongestionControl¶

Priority¶

Subscriber¶

PullSubscriber¶

Reliability¶

Query¶

Selector¶

QueryTarget¶

QueryConsolidation¶

Reply¶

Queryable¶

ZenohId¶

Timestamp¶