Struct vector_buffers::topology::builder::TopologyBuilder

pub struct TopologyBuilder<T: Bufferable> { /* private fields */ }

Builder for constructing buffer topologies.

Implementations

impl<T: Bufferable> TopologyBuilder<T>

pub fn stage<S>(&mut self, stage: S, when_full: WhenFull) -> &mut Self

where S: IntoBuffer<T> + 'static,

Adds a new stage to the buffer topology.

The “when full” behavior can be optionally configured here. If no behavior is specified, and an overflow buffer is not added to the topology after this, then the “when full” behavior will use a default value of “block”. If a “when full” behavior is specified, and an overflow buffer is added to the topology after this, then the specified “when full” behavior will be ignored and will be set to “overflow” mode.

Callers can configure what to do when a buffer is full by setting when_full. Three modes are available – block, drop newest, and overflow – which are documented in more detail by BufferSender.

Two notes about what modes are not valid in certain scenarios:

• the innermost stage (the last stage given to the builder) cannot be set to “overflow” mode, as there is no other stage to overflow to
• a stage cannot use the “block” or “drop newest” mode when there is a subsequent stage, and must user the “overflow” mode

Any occurrence of either of these scenarios will result in an error during build.

pub async fn build( self, buffer_id: String, span: Span, ) -> Result<(BufferSender<T>, BufferReceiver<T>), TopologyError>

Consumes this builder, returning the sender and receiver that can be used by components.

Errors

If there was a configuration error with one of the stages, an error variant will be returned explaining the issue.

impl<T: Bufferable> TopologyBuilder<T>

pub async fn standalone_memory( max_events: NonZeroUsize, when_full: WhenFull, receiver_span: &Span, ) -> (BufferSender<T>, BufferReceiver<T>)

Creates a memory-only buffer topology.

The overflow mode (i.e. WhenFull) can be configured to either block or drop the newest values, but cannot be configured to use overflow mode. If overflow mode is selected, it will be changed to blocking mode.

This is a convenience method for vector as it is used for inter-transform channels, and we can simplifying needing to require callers to do all the boilerplate to create the builder, create the stage, installing buffer usage metrics that aren’t required, and so on.

Trait Implementations

impl<T: Bufferable> Default for TopologyBuilder<T>

fn default() -> Self

Returns the “default value” for a type.