Struct SimpleConsumer

pub struct SimpleConsumer { /* private fields */ }

SimpleConsumer is a lightweight consumer to consume messages from RocketMQ proxy.

If you want to fully control the message consumption operation by yourself, the simple consumer should be your first consideration.

SimpleConsumer is a thin wrapper of internal client struct that shoulders the actual workloads. Most of its methods take shared reference so that application developers may use it at will.

SimpleConsumer is Send and Sync by design, so that developers may get started easily.

Implementations

impl SimpleConsumer

pub fn new( option: SimpleConsumerOption, client_option: ClientOption, ) -> Result<Self, ClientError>

Create a new simple consumer instance

pub async fn start(&mut self) -> Result<(), ClientError>

Start the simple consumer

pub async fn shutdown(self) -> Result<(), ClientError>

pub async fn receive( &self, topic: impl AsRef<str>, expression: &FilterExpression, ) -> Result<Vec<MessageView>, ClientError>

receive messages from the specified topic

Arguments

• topic - the topic for receiving messages
• expression - the subscription for the topic

pub async fn receive_with( &self, topic: impl AsRef<str>, expression: &FilterExpression, batch_size: i32, invisible_duration: Duration, ) -> Result<Vec<MessageView>, ClientError>

receive messages from the specified topic with batch size and invisible duration

Arguments

• topic - the topic for receiving messages
• expression - the subscription for the topic
• batch_size - max message num of server returned
• invisible_duration - set the invisible duration of messages that return from the server, these messages will not be visible to other consumers unless timeout

pub async fn ack( &self, ack_entry: &(impl AckMessageEntry + 'static), ) -> Result<(), ClientError>

Ack the specified message

It is important to acknowledge every consumed message, otherwise, they will be received again after the invisible duration

Arguments

• ack_entry - special message view with handle want to ack

Trait Implementations

impl Debug for SimpleConsumer

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

Formats the value using the given formatter.