Struct KafkaEventReader 

pub struct KafkaEventReader<'w, 's, T: BusEvent + Event> { /* private fields */ }

Kafka-specific BusEventReader implementation that can optionally perform manual commits and expose consumer lag metrics.

Implementations

impl<'w, 's, T: BusEvent + Event> KafkaEventReader<'w, 's, T>

pub fn read<C: EventBusConfig>(&mut self, config: &C) -> Vec<EventWrapper<T>>

Read all messages for the supplied Kafka configuration. When manual commit is requested (auto commit disabled) the reader ensures the backend has manual commit mode enabled for the consumer group before returning events.

pub fn commit( &mut self, config: &KafkaConsumerConfig, event: &EventWrapper<T>, ) -> Result<(), KafkaReaderError>

Commit the supplied event using Kafka manual offsets. The configuration used to read the event must have auto commit disabled.

pub fn consumer_lag( &self, config: &KafkaConsumerConfig, ) -> Result<HashMap<String, i64>, KafkaReaderError>

Fetch consumer lag per topic for the supplied configuration.

Trait Implementations

impl<'w, 's, T: BusEvent + Event> BusEventReader<T> for KafkaEventReader<'w, 's, T>

fn read<C: EventBusConfig>(&mut self, config: &C) -> Vec<EventWrapper<T>>

Drain the buffered events for the supplied configuration.

impl<T: BusEvent + Event> SystemParam for KafkaEventReader<'_, '_, T>

type State = FetchState<T>

Used to store data which persists across invocations of a system.

type Item<'w, 's> = KafkaEventReader<'w, 's, T>

The item type returned when constructing this system param. The value of this associated type should be Self, instantiated with new lifetimes.

fn init_state(world: &mut World, system_meta: &mut SystemMeta) -> Self::State

Registers any World access used by this SystemParam and creates a new instance of this param’s State.

unsafe fn new_archetype( state: &mut Self::State, archetype: &Archetype, system_meta: &mut SystemMeta, )

For the specified Archetype, registers the components accessed by this SystemParam (if applicable).a

fn apply(state: &mut Self::State, system_meta: &SystemMeta, world: &mut World)

Applies any deferred mutations stored in this SystemParam’s state. This is used to apply Commands during ApplyDeferred.

fn queue( state: &mut Self::State, system_meta: &SystemMeta, world: DeferredWorld<'_>, )

Queues any deferred mutations to be applied at the next ApplyDeferred.

unsafe fn validate_param<'w, 's>( state: &'s Self::State, _system_meta: &SystemMeta, _world: UnsafeWorldCell<'w>, ) -> Result<(), SystemParamValidationError>

Validates that the param can be acquired by the get_param.

unsafe fn get_param<'w, 's>( state: &'s mut Self::State, system_meta: &SystemMeta, world: UnsafeWorldCell<'w>, change_tick: Tick, ) -> Self::Item<'w, 's>

Creates a parameter to be passed into a SystemParamFunction.

impl<'w, 's, T: BusEvent + Event> ReadOnlySystemParam for KafkaEventReader<'w, 's, T>

where Local<'s, Vec<EventWrapper<T>>>: ReadOnlySystemParam, Option<ResMut<'w, DrainedTopicMetadata>>: ReadOnlySystemParam, Local<'s, HashMap<String, usize>>: ReadOnlySystemParam, Option<Res<'w, KafkaCommitQueue>>: ReadOnlySystemParam, Option<Res<'w, KafkaLagCacheResource>>: ReadOnlySystemParam, Option<Res<'w, ProvisionedTopology>>: ReadOnlySystemParam, Local<'s, HashSet<String>>: ReadOnlySystemParam, EventWriter<'w, EventBusError<T>>: ReadOnlySystemParam,