## Publisher

# Struct Publisher

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    pub struct Publisher { /* private fields */ }

Expand description

A `Publisher` sends messages to a specific topic. It manages message batching and sending in a background task.

Publishers are created via a `Client`.

    let client = Client::builder().build().await?;
    let publisher = client.publisher("projects/my-project/topics/my-topic").build();
    let message_id = publisher.publish(PubsubMessage::new().set_data("Hello, World"));

## Implementations§

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### impl Publisher

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#### pub fn publish(&self, msg: PubsubMessage) -> PublishHandle ⓘ

Publishes a message to the topic.

    let message_id = publisher.publish(PubsubMessage::new().set_data("Hello, World")).await?;

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#### pub async fn flush(&self)

Flushes all outstanding messages.

This method sends any messages that have been published but not yet sent, regardless of the configured batching options (`delay_threshold`, etc.).

This method is `async` and returns only after all publish attempts for the messages in the snapshot have completed. A “completed” attempt means the message has either been successfully sent, or has failed permanently after exhausting any applicable retry policies.

After flush()` returns, the final result of each individual publish operation (i.e., a success with a message ID or a terminal error) will be available on its corresponding PublishHandle.

Messages published after `flush()` is called will be buffered for a subsequent batch and are not included in this flush operation.

##### §Example

    // Publish some messages. They will be buffered according to batching options.
    let handle1 = publisher.publish(PubsubMessage::new().set_data("foo".to_string()));
    let handle2 = publisher.publish(PubsubMessage::new().set_data("bar".to_string()));

    // Flush ensures that these messages are sent immediately and waits for
    // the send to complete.
    publisher.flush().await;

    // The results for handle1 and handle2 are available.
    let id1 = handle1.await?;
    let id2 = handle2.await?;

## Trait Implementations§

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### impl Clone for Publisher

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#### fn clone(&self) -> Publisher

Returns a duplicate of the value. Read more
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#### fn clone_from(&mut self, source: &Self)

Performs copy-assignment from `source`. Read more
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### impl Debug for Publisher

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#### fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter. Read more

## Auto Trait Implementations§

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### impl Freeze for Publisher

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### impl RefUnwindSafe for Publisher

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### impl Send for Publisher

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### impl Sync for Publisher

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### impl Unpin for Publisher

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### impl UnwindSafe for Publisher

## Blanket Implementations§

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### impl<T> Any for T
where T: 'static + ?Sized,

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#### fn type_id(&self) -> TypeId

Gets the `TypeId` of `self`. Read more
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### impl<T> Borrow<T> for T
where T: ?Sized,

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#### fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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### impl<T> BorrowMut<T> for T
where T: ?Sized,

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#### fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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### impl<T> CloneToUninit for T
where T: Clone,

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#### unsafe fn clone_to_uninit(&self, dest: *mut u8)

🔬This is a nightly-only experimental API. (`clone_to_uninit`)
Performs copy-assignment from `self` to `dest`. Read more
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### impl<T> From<T> for T

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#### fn from(t: T) -> T

Returns the argument unchanged.

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### impl<T> Instrument for T

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#### fn instrument(self, span: Span) -> Instrumented<Self>

Instruments this type with the provided [`Span`], returning an `Instrumented` wrapper. Read more
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#### fn in_current_span(self) -> Instrumented<Self>

Instruments this type with the current `Span`, returning an `Instrumented` wrapper. Read more
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### impl<T, U> Into<U> for T
where U: From<T>,

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#### fn into(self) -> U

Calls `U::from(self)`.

That is, this conversion is whatever the implementation of `From<T> for U` chooses to do.

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### impl<T> IntoRequest<T> for T

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#### fn into_request(self) -> Request<T>

Wrap the input message `T` in a `tonic::Request`
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### impl<L> LayerExt<L> for L

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#### fn named_layer<S>(&self, service: S) -> Layered<<L as Layer<S>>::Service, S>
where L: Layer<S>,

Applies the layer to a service and wraps it in [`Layered`].
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### impl<T> PolicyExt for T
where T: ?Sized,

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#### fn and<P, B, E>(self, other: P) -> And<T, P>
where T: Policy<B, E>, P: Policy<B, E>,

Create a new `Policy` that returns [`Action::Follow`] only if `self` and `other` return `Action::Follow`. Read more
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#### fn or<P, B, E>(self, other: P) -> Or<T, P>
where T: Policy<B, E>, P: Policy<B, E>,

Create a new `Policy` that returns [`Action::Follow`] if either `self` or `other` returns `Action::Follow`. Read more
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### impl<T> ToOwned for T
where T: Clone,

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#### type Owned = T

The resulting type after obtaining ownership.
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#### fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more
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#### fn clone_into(&self, target: &mut T)

Uses borrowed data to replace owned data, usually by cloning. Read more
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### impl<T, U> TryFrom<U> for T
where U: Into<T>,

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#### type Error = Infallible

The type returned in the event of a conversion error.
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#### fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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### impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

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#### type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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#### fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.
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### impl<V, T> VZip<V> for T
where V: MultiLane<T>,

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#### fn vzip(self) -> V

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### impl<T> WithSubscriber for T

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#### fn with_subscriber<S>(self, subscriber: S) -> WithDispatch<Self>
where S: Into<Dispatch>,

Attaches the provided `Subscriber` to this type, returning a [`WithDispatch`] wrapper. Read more
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#### fn with_current_subscriber(self) -> WithDispatch<Self>

Attaches the current default `Subscriber` to this type, returning a [`WithDispatch`] wrapper. Read more