rust_rabbit/
consumer.rs

1use crate::{
2    connection::ConnectionManager,
3    error::{RabbitError, Result},
4    metrics::RustRabbitMetrics,
5    publisher::{CustomExchangeDeclareOptions, CustomQueueDeclareOptions, Publisher},
6    retry::{DelayedMessageExchange, RetryPolicy},
7};
8use async_trait::async_trait;
9use futures::StreamExt;
10use lapin::{
11    message::Delivery,
12    options::{
13        BasicAckOptions, BasicConsumeOptions, BasicNackOptions, BasicPublishOptions,
14        ExchangeDeclareOptions, QueueBindOptions, QueueDeclareOptions as LapinQueueDeclareOptions,
15    },
16    types::FieldTable,
17    BasicProperties, Channel, ExchangeKind,
18};
19use serde::de::DeserializeOwned;
20use std::sync::Arc;
21use tokio::sync::Semaphore;
22use tracing::{debug, error, info, warn};
23
24/// Message handler trait for processing consumed messages
25#[async_trait]
26pub trait MessageHandler<T>: Send + Sync + 'static
27where
28    T: DeserializeOwned + Send + Sync,
29{
30    /// Handle a received message
31    async fn handle(&self, message: T, context: MessageContext) -> MessageResult;
32}
33
34/// Context information for a received message
35#[derive(Debug, Clone)]
36pub struct MessageContext {
37    pub message_id: Option<String>,
38    pub correlation_id: Option<String>,
39    pub reply_to: Option<String>,
40    pub delivery_tag: u64,
41    pub redelivered: bool,
42    pub exchange: String,
43    pub routing_key: String,
44    pub headers: FieldTable,
45    pub timestamp: Option<u64>,
46    pub retry_count: u32,
47}
48
49/// Result of message processing
50#[derive(Debug)]
51pub enum MessageResult {
52    /// Message processed successfully
53    Ack,
54    /// Message processing failed, should be retried
55    Retry,
56    /// Message processing failed permanently, should be rejected
57    Reject,
58    /// Message processing failed, should be requeued
59    Requeue,
60}
61
62/// Consumer options
63#[derive(Debug, Clone)]
64pub struct ConsumerOptions {
65    /// Queue name to consume from
66    pub queue_name: String,
67
68    /// Consumer tag (optional)
69    pub consumer_tag: Option<String>,
70
71    /// Number of concurrent message processors
72    pub concurrency: usize,
73
74    /// Prefetch count (QoS)
75    pub prefetch_count: Option<u16>,
76
77    /// Auto-declare queue before consuming
78    pub auto_declare_queue: bool,
79
80    /// Queue declaration options
81    pub queue_options: CustomQueueDeclareOptions,
82
83    /// Auto-declare exchange and bind to queue
84    pub auto_declare_exchange: bool,
85
86    /// Exchange name (if not provided, uses queue_name as exchange name)
87    pub exchange_name: Option<String>,
88
89    /// Exchange declaration options
90    pub exchange_options: CustomExchangeDeclareOptions,
91
92    /// Routing key for binding queue to exchange (default: queue_name)
93    pub routing_key: Option<String>,
94
95    /// Retry policy for failed messages
96    pub retry_policy: Option<RetryPolicy>,
97
98    /// Dead letter exchange for failed messages
99    pub dead_letter_exchange: Option<String>,
100
101    /// Auto-ack messages (not recommended for production)
102    pub auto_ack: bool,
103
104    /// Consumer exclusive mode
105    pub exclusive: bool,
106
107    /// Consumer arguments
108    pub arguments: FieldTable,
109}
110
111impl ConsumerOptions {
112    /// Create a new consumer options builder
113    pub fn builder<S: Into<String>>(queue_name: S) -> ConsumerOptionsBuilder {
114        ConsumerOptionsBuilder::new(queue_name.into())
115    }
116}
117
118/// Builder for ConsumerOptions
119#[derive(Debug, Clone)]
120pub struct ConsumerOptionsBuilder {
121    queue_name: String,
122    consumer_tag: Option<String>,
123    concurrency: usize,
124    prefetch_count: Option<u16>,
125    auto_declare_queue: bool,
126    queue_options: CustomQueueDeclareOptions,
127    auto_declare_exchange: bool,
128    exchange_name: Option<String>,
129    exchange_options: CustomExchangeDeclareOptions,
130    routing_key: Option<String>,
131    retry_policy: Option<RetryPolicy>,
132    dead_letter_exchange: Option<String>,
133    auto_ack: bool,
134    exclusive: bool,
135    arguments: FieldTable,
136}
137
138impl ConsumerOptionsBuilder {
139    /// Create a new builder with default values
140    pub fn new(queue_name: String) -> Self {
141        Self {
142            queue_name,
143            consumer_tag: None,
144            concurrency: 1,
145            prefetch_count: Some(10),
146            auto_declare_queue: false,
147            queue_options: CustomQueueDeclareOptions::default(),
148            auto_declare_exchange: false,
149            exchange_name: None,
150            exchange_options: CustomExchangeDeclareOptions::default(),
151            routing_key: None,
152            retry_policy: None,
153            dead_letter_exchange: None,
154            auto_ack: false,
155            exclusive: false,
156            arguments: FieldTable::default(),
157        }
158    }
159
160    /// Set consumer tag
161    pub fn consumer_tag<S: Into<String>>(mut self, tag: S) -> Self {
162        self.consumer_tag = Some(tag.into());
163        self
164    }
165
166    /// Set concurrency level
167    pub fn concurrency(mut self, concurrency: usize) -> Self {
168        self.concurrency = concurrency;
169        self
170    }
171
172    /// Set prefetch count
173    pub fn prefetch_count(mut self, count: u16) -> Self {
174        self.prefetch_count = Some(count);
175        self
176    }
177
178    /// Disable prefetch limit
179    pub fn no_prefetch_limit(mut self) -> Self {
180        self.prefetch_count = None;
181        self
182    }
183
184    /// Enable auto-declare queue
185    pub fn auto_declare_queue(mut self) -> Self {
186        self.auto_declare_queue = true;
187        self
188    }
189
190    /// Enable auto-declare exchange and bind to queue
191    pub fn auto_declare_exchange(mut self) -> Self {
192        self.auto_declare_exchange = true;
193        self
194    }
195
196    /// Set exchange name (if not set, uses queue_name)
197    pub fn exchange_name<S: Into<String>>(mut self, name: S) -> Self {
198        self.exchange_name = Some(name.into());
199        self
200    }
201
202    /// Set exchange options
203    pub fn exchange_options(mut self, options: CustomExchangeDeclareOptions) -> Self {
204        self.exchange_options = options;
205        self
206    }
207
208    /// Set routing key for binding (default: queue_name)
209    pub fn routing_key<S: Into<String>>(mut self, key: S) -> Self {
210        self.routing_key = Some(key.into());
211        self
212    }
213
214    /// Set queue options
215    pub fn queue_options(mut self, options: CustomQueueDeclareOptions) -> Self {
216        self.queue_options = options;
217        self
218    }
219
220    /// Set retry policy
221    pub fn retry_policy(mut self, policy: RetryPolicy) -> Self {
222        self.retry_policy = Some(policy);
223        self
224    }
225
226    /// Set dead letter exchange
227    pub fn dead_letter_exchange<S: Into<String>>(mut self, exchange: S) -> Self {
228        self.dead_letter_exchange = Some(exchange.into());
229        self
230    }
231
232    /// Enable auto-ack (not recommended for production)
233    pub fn auto_ack(mut self) -> Self {
234        self.auto_ack = true;
235        self
236    }
237
238    /// Enable manual ack (recommended for production)
239    pub fn manual_ack(mut self) -> Self {
240        self.auto_ack = false;
241        self
242    }
243
244    /// Enable exclusive mode
245    pub fn exclusive(mut self) -> Self {
246        self.exclusive = true;
247        self
248    }
249
250    /// Configure for high throughput
251    pub fn high_throughput(mut self) -> Self {
252        self.concurrency = 20;
253        self.prefetch_count = Some(50);
254        self.auto_ack = false;
255        self
256    }
257
258    /// Configure for reliability (lower throughput but safer)
259    pub fn reliable(mut self) -> Self {
260        self.concurrency = 1;
261        self.prefetch_count = Some(1);
262        self.auto_ack = false;
263        self
264    }
265
266    /// Configure for development (simpler settings)
267    pub fn development(mut self) -> Self {
268        self.concurrency = 1;
269        self.prefetch_count = Some(1);
270        self.auto_ack = true;
271        self.auto_declare_queue = true;
272        self.auto_declare_exchange = true; // Auto-declare exchange in development
273        self
274    }
275
276    /// Configure for minutes exponential retry (1min, 2min, 4min, 8min, 16min - max 5 retries)
277    /// This preset automatically sets up:
278    /// - Auto declare queue and exchange
279    /// - Retry policy with minutes exponential backoff
280    /// - Dead letter exchange/queue based on queue name
281    /// - Reliable processing settings
282    pub fn minutes_retry(mut self) -> Self {
283        let queue_name = self.queue_name.clone();
284
285        self.auto_declare_queue = true;
286        self.auto_declare_exchange = true;
287        self.retry_policy = Some(RetryPolicy::minutes_exponential_for_queue(&queue_name));
288        self.concurrency = 1; // Process one at a time for reliable retries
289        self.prefetch_count = Some(1); // One message at a time
290        self.auto_ack = false; // Manual ack for retry support
291        self
292    }
293
294    /// Build the final configuration
295    pub fn build(self) -> ConsumerOptions {
296        ConsumerOptions {
297            queue_name: self.queue_name,
298            consumer_tag: self.consumer_tag,
299            concurrency: self.concurrency,
300            prefetch_count: self.prefetch_count,
301            auto_declare_queue: self.auto_declare_queue,
302            queue_options: self.queue_options,
303            auto_declare_exchange: self.auto_declare_exchange,
304            exchange_name: self.exchange_name,
305            exchange_options: self.exchange_options,
306            routing_key: self.routing_key,
307            retry_policy: self.retry_policy,
308            dead_letter_exchange: self.dead_letter_exchange,
309            auto_ack: self.auto_ack,
310            exclusive: self.exclusive,
311            arguments: self.arguments,
312        }
313    }
314}
315
316impl Default for ConsumerOptions {
317    fn default() -> Self {
318        Self {
319            queue_name: String::new(),
320            consumer_tag: None,
321            concurrency: 1,
322            prefetch_count: Some(10),
323            auto_declare_queue: false,
324            queue_options: CustomQueueDeclareOptions::default(),
325            auto_declare_exchange: false,
326            exchange_name: None,
327            exchange_options: CustomExchangeDeclareOptions::default(),
328            routing_key: None,
329            retry_policy: None,
330            dead_letter_exchange: None,
331            auto_ack: false,
332            exclusive: false,
333            arguments: FieldTable::default(),
334        }
335    }
336}
337
338/// Consumer for receiving messages from RabbitMQ
339pub struct Consumer {
340    #[allow(dead_code)] // Will be used for connection health monitoring
341    connection_manager: ConnectionManager,
342    options: ConsumerOptions,
343    channel: Channel,
344    semaphore: Arc<Semaphore>,
345    metrics: Option<RustRabbitMetrics>,
346    publisher: Publisher,
347}
348
349impl Consumer {
350    /// Create a new consumer
351    pub async fn new(
352        connection_manager: ConnectionManager,
353        options: ConsumerOptions,
354    ) -> Result<Self> {
355        let connection = connection_manager.get_connection().await?;
356        let channel = connection.create_channel().await?;
357
358        // Set QoS if prefetch_count is specified
359        if let Some(prefetch_count) = options.prefetch_count {
360            debug!("Setting prefetch_count: {}", prefetch_count);
361            channel
362                .basic_qos(
363                    prefetch_count,
364                    lapin::options::BasicQosOptions { global: false },
365                )
366                .await
367                .map_err(|e| {
368                    error!("Failed to set QoS prefetch_count={}: {}", prefetch_count, e);
369                    RabbitError::Connection(e)
370                })?;
371            debug!("Successfully set prefetch_count: {}", prefetch_count);
372        }
373
374        // Declare queue if auto_declare is enabled
375        if options.auto_declare_queue {
376            Self::declare_queue_and_exchange(&channel, &options).await?;
377        }
378
379        let semaphore = Arc::new(Semaphore::new(options.concurrency));
380
381        // Setup delayed exchange infrastructure if retry policy is configured
382        if options.retry_policy.is_some() {
383            Self::setup_retry_infrastructure(&connection_manager, &options).await?;
384        }
385
386        let publisher = Publisher::new(connection_manager.clone());
387
388        Ok(Self {
389            connection_manager,
390            options,
391            channel,
392            semaphore,
393            metrics: None,
394            publisher,
395        })
396    }
397
398    /// Set metrics for this consumer
399    pub fn set_metrics(&mut self, metrics: RustRabbitMetrics) {
400        self.metrics = Some(metrics);
401    }
402
403    /// Start consuming messages with the given handler
404    pub async fn consume<T, H>(&self, handler: Arc<H>) -> Result<()>
405    where
406        T: DeserializeOwned + Send + Sync + 'static,
407        H: MessageHandler<T>,
408    {
409        let consumer_tag = self
410            .options
411            .consumer_tag
412            .clone()
413            .unwrap_or_else(|| format!("rust-rabbit-{}", uuid::Uuid::new_v4()));
414
415        let consume_options = BasicConsumeOptions {
416            no_local: false,
417            no_ack: self.options.auto_ack,
418            exclusive: self.options.exclusive,
419            nowait: false,
420        };
421
422        let mut consumer = self
423            .channel
424            .basic_consume(
425                &self.options.queue_name,
426                &consumer_tag,
427                consume_options,
428                self.options.arguments.clone(),
429            )
430            .await?;
431
432        info!(
433            "Started consuming from queue: {} with tag: {}",
434            self.options.queue_name, consumer_tag
435        );
436
437        while let Some(delivery) = consumer.next().await {
438            let delivery = delivery?;
439            let permit = self
440                .semaphore
441                .clone()
442                .acquire_owned()
443                .await
444                .map_err(|e| RabbitError::Generic(e.into()))?;
445
446            let handler = handler.clone();
447            let retry_policy = self.options.retry_policy.clone();
448            let dead_letter_exchange = self.options.dead_letter_exchange.clone();
449            let channel = self.channel.clone();
450            let publisher = self.publisher.clone();
451            let exchange_name = self
452                .options
453                .exchange_name
454                .clone()
455                .unwrap_or_else(|| self.options.queue_name.clone());
456
457            // Process message in a separate task
458            tokio::spawn(async move {
459                let _permit = permit; // Hold the permit for the duration of processing
460
461                if let Err(e) = Self::process_message::<T, H>(
462                    delivery,
463                    handler,
464                    retry_policy,
465                    dead_letter_exchange,
466                    channel,
467                    publisher,
468                    exchange_name,
469                )
470                .await
471                {
472                    error!("Error processing message: {}", e);
473                }
474            });
475        }
476
477        warn!(
478            "Consumer stream ended for queue: {}",
479            self.options.queue_name
480        );
481        Ok(())
482    }
483
484    /// Process a single message
485    async fn process_message<T, H>(
486        delivery: Delivery,
487        handler: Arc<H>,
488        retry_policy: Option<RetryPolicy>,
489        dead_letter_exchange: Option<String>,
490        channel: Channel,
491        publisher: Publisher,
492        exchange_name: String,
493    ) -> Result<()>
494    where
495        T: DeserializeOwned + Send + Sync,
496        H: MessageHandler<T>,
497    {
498        let context = Self::build_message_context(&delivery);
499
500        // Deserialize message
501        let message: T = match serde_json::from_slice(&delivery.data) {
502            Ok(msg) => msg,
503            Err(e) => {
504                error!("Failed to deserialize message: {}", e);
505                Self::reject_message(&delivery, &channel, false).await?;
506                return Ok(());
507            }
508        };
509
510        // Handle message
511        let result = handler.handle(message, context.clone()).await;
512
513        match result {
514            MessageResult::Ack => {
515                Self::ack_message(&delivery, &channel).await?;
516                debug!("Message acknowledged: {}", delivery.delivery_tag);
517            }
518            MessageResult::Retry => {
519                if let Some(ref policy) = retry_policy {
520                    Self::handle_retry(
521                        &delivery,
522                        &channel,
523                        &context,
524                        policy,
525                        &publisher,
526                        &exchange_name,
527                    )
528                    .await?;
529                } else {
530                    Self::reject_message(&delivery, &channel, true).await?;
531                }
532            }
533            MessageResult::Reject => {
534                if let Some(ref dle) = dead_letter_exchange {
535                    Self::send_to_dead_letter(&delivery, dle, &context, &publisher).await?;
536                } else {
537                    Self::reject_message(&delivery, &channel, false).await?;
538                }
539            }
540            MessageResult::Requeue => {
541                Self::reject_message(&delivery, &channel, true).await?;
542            }
543        }
544
545        Ok(())
546    }
547
548    /// Build message context from delivery
549    fn build_message_context(delivery: &Delivery) -> MessageContext {
550        let properties = &delivery.properties;
551
552        MessageContext {
553            message_id: properties.message_id().as_ref().map(|s| s.to_string()),
554            correlation_id: properties.correlation_id().as_ref().map(|s| s.to_string()),
555            reply_to: properties.reply_to().as_ref().map(|s| s.to_string()),
556            delivery_tag: delivery.delivery_tag,
557            redelivered: delivery.redelivered,
558            exchange: delivery.exchange.to_string(),
559            routing_key: delivery.routing_key.to_string(),
560            headers: properties.headers().clone().unwrap_or_default(),
561            timestamp: *properties.timestamp(),
562            retry_count: Self::get_retry_count_from_headers(
563                properties
564                    .headers()
565                    .as_ref()
566                    .unwrap_or(&FieldTable::default()),
567            ),
568        }
569    }
570
571    /// Get retry count from message headers
572    fn get_retry_count_from_headers(headers: &FieldTable) -> u32 {
573        headers
574            .inner()
575            .get("x-retry-count")
576            .and_then(|v| match v {
577                lapin::types::AMQPValue::LongInt(count) => Some(*count as u32),
578                lapin::types::AMQPValue::LongLongInt(count) => Some(*count as u32),
579                _ => None,
580            })
581            .unwrap_or(0)
582    }
583
584    /// Acknowledge a message
585    async fn ack_message(delivery: &Delivery, channel: &Channel) -> Result<()> {
586        channel
587            .basic_ack(delivery.delivery_tag, BasicAckOptions::default())
588            .await?;
589        Ok(())
590    }
591
592    /// Reject a message
593    async fn reject_message(delivery: &Delivery, channel: &Channel, requeue: bool) -> Result<()> {
594        channel
595            .basic_nack(
596                delivery.delivery_tag,
597                BasicNackOptions {
598                    multiple: false,
599                    requeue,
600                },
601            )
602            .await?;
603        Ok(())
604    }
605
606    /// Handle retry logic
607    async fn handle_retry(
608        delivery: &Delivery,
609        channel: &Channel,
610        context: &MessageContext,
611        retry_policy: &RetryPolicy,
612        publisher: &Publisher,
613        exchange_name: &str,
614    ) -> Result<()> {
615        if context.retry_count >= retry_policy.max_retries {
616            warn!(
617                "Max retries exceeded for message: {}",
618                delivery.delivery_tag
619            );
620
621            // Send to dead letter exchange if configured
622            if let Some(ref dle) = retry_policy.dead_letter_exchange {
623                Self::send_to_dead_letter(delivery, dle, context, publisher).await?;
624            } else {
625                Self::reject_message(delivery, channel, false).await?;
626            }
627            return Ok(());
628        }
629
630        // Calculate delay for next retry
631        let delay = retry_policy.calculate_delay(context.retry_count);
632        let delayed_exchange_name = format!("{}.retry", exchange_name);
633
634        // Create retry message with updated headers
635        let mut headers = delivery.properties.headers().clone().unwrap_or_default();
636        headers.insert(
637            "x-retry-count".into(),
638            lapin::types::AMQPValue::LongInt((context.retry_count + 1) as i32),
639        );
640        headers.insert(
641            "x-original-queue".into(),
642            lapin::types::AMQPValue::LongString(context.routing_key.clone().into()),
643        );
644
645        // Build properties with delay header for delayed message exchange
646        let mut properties = BasicProperties::default()
647            .with_content_type("application/json".into())
648            .with_delivery_mode(2)
649            .with_headers(headers);
650
651        // Add delay header for delayed message exchange
652        let mut delay_headers = properties.headers().clone().unwrap_or_default();
653        delay_headers.insert(
654            "x-delay".into(),
655            lapin::types::AMQPValue::LongLongInt(delay.as_millis() as i64),
656        );
657        properties = properties.with_headers(delay_headers);
658
659        // Publish to delayed exchange using channel
660        channel
661            .basic_publish(
662                &delayed_exchange_name,
663                &context.routing_key,
664                BasicPublishOptions::default(),
665                &delivery.data,
666                properties,
667            )
668            .await?;
669
670        info!(
671            "Retrying message after {:?} (attempt {})",
672            delay,
673            context.retry_count + 1
674        );
675
676        // Acknowledge the original message since we've republished it
677        Self::ack_message(delivery, channel).await?;
678
679        Ok(())
680    }
681
682    /// Send message to dead letter exchange
683    async fn send_to_dead_letter(
684        delivery: &Delivery,
685        dead_letter_exchange: &str,
686        _context: &MessageContext,
687        publisher: &Publisher,
688    ) -> Result<()> {
689        // Create dead letter message with additional headers
690        let mut headers = delivery.properties.headers().clone().unwrap_or_default();
691        headers.insert(
692            "x-death-reason".into(),
693            lapin::types::AMQPValue::LongString("max-retries-exceeded".into()),
694        );
695        headers.insert(
696            "x-death-time".into(),
697            lapin::types::AMQPValue::LongLongInt(chrono::Utc::now().timestamp_millis()),
698        );
699
700        // Build properties for dead letter message
701        let properties = BasicProperties::default()
702            .with_content_type("application/json".into())
703            .with_delivery_mode(2)
704            .with_headers(headers);
705
706        // Get connection and publish to dead letter exchange
707        let connection = publisher.get_connection().await?;
708        let dlx_channel = connection.create_channel().await?;
709
710        dlx_channel
711            .basic_publish(
712                dead_letter_exchange,
713                "dead-letter", // routing key for dead letter
714                BasicPublishOptions::default(),
715                &delivery.data,
716                properties,
717            )
718            .await?;
719
720        warn!(
721            "Sent message to dead letter exchange: {}",
722            dead_letter_exchange
723        );
724
725        Ok(())
726    }
727
728    /// Stop consuming (close the consumer)
729    pub async fn stop(&self) -> Result<()> {
730        // The consumer will stop when the channel is closed
731        // or when the stream ends
732        info!("Stopping consumer for queue: {}", self.options.queue_name);
733        Ok(())
734    }
735
736    /// Declare queue and optionally exchange with binding
737    async fn declare_queue_and_exchange(
738        channel: &Channel,
739        options: &ConsumerOptions,
740    ) -> Result<()> {
741        // First declare the queue
742        let queue_options = LapinQueueDeclareOptions {
743            passive: options.queue_options.passive,
744            durable: options.queue_options.durable,
745            exclusive: options.queue_options.exclusive,
746            auto_delete: options.queue_options.auto_delete,
747            nowait: false,
748        };
749
750        channel
751            .queue_declare(
752                &options.queue_name,
753                queue_options,
754                options.queue_options.arguments.clone(),
755            )
756            .await?;
757
758        debug!("Declared queue: {}", options.queue_name);
759
760        // Declare exchange and bind if auto_declare_exchange is enabled
761        if options.auto_declare_exchange {
762            let exchange_name = options
763                .exchange_name
764                .as_ref()
765                .unwrap_or(&options.queue_name);
766
767            // Declare exchange
768            let exchange_options = ExchangeDeclareOptions {
769                passive: options.exchange_options.passive,
770                durable: options.exchange_options.durable,
771                auto_delete: options.exchange_options.auto_delete,
772                internal: options.exchange_options.internal,
773                nowait: false,
774            };
775
776            // Handle delayed message exchange if needed
777            let mut arguments = options.exchange_options.arguments.clone();
778            if matches!(options.exchange_options.exchange_type, ExchangeKind::Custom(ref kind) if kind == "x-delayed-message")
779            {
780                arguments.insert(
781                    "x-delayed-type".into(),
782                    lapin::types::AMQPValue::LongString(
783                        match options.exchange_options.original_type {
784                            ExchangeKind::Direct => "direct".into(),
785                            ExchangeKind::Fanout => "fanout".into(),
786                            ExchangeKind::Topic => "topic".into(),
787                            ExchangeKind::Headers => "headers".into(),
788                            ExchangeKind::Custom(ref s) => s.clone().into(),
789                        },
790                    ),
791                );
792            }
793
794            channel
795                .exchange_declare(
796                    exchange_name,
797                    options.exchange_options.exchange_type.clone(),
798                    exchange_options,
799                    arguments,
800                )
801                .await?;
802
803            debug!("Declared exchange: {}", exchange_name);
804
805            // Bind queue to exchange
806            let routing_key = options.routing_key.as_ref().unwrap_or(&options.queue_name);
807
808            channel
809                .queue_bind(
810                    &options.queue_name,
811                    exchange_name,
812                    routing_key,
813                    QueueBindOptions::default(),
814                    FieldTable::default(),
815                )
816                .await?;
817
818            debug!(
819                "Bound queue '{}' to exchange '{}' with routing key '{}'",
820                options.queue_name, exchange_name, routing_key
821            );
822        }
823
824        Ok(())
825    }
826
827    /// Setup retry infrastructure (delayed exchange) if retry policy is configured
828    async fn setup_retry_infrastructure(
829        connection_manager: &ConnectionManager,
830        options: &ConsumerOptions,
831    ) -> Result<()> {
832        if let Some(ref retry_policy) = options.retry_policy {
833            // Create delayed exchange name
834            let delayed_exchange_name = format!(
835                "{}.retry",
836                options
837                    .exchange_name
838                    .as_ref()
839                    .unwrap_or(&options.queue_name)
840            );
841
842            // Create DelayedMessageExchange instance and setup infrastructure
843            let delayed_exchange = DelayedMessageExchange::new(
844                connection_manager.clone(),
845                delayed_exchange_name.clone(),
846                retry_policy.clone(),
847            );
848
849            // Setup the delayed exchange and dead letter infrastructure
850            delayed_exchange.setup().await?;
851
852            // Setup queue binding for retry mechanism
853            delayed_exchange
854                .setup_queue_retry(&options.queue_name)
855                .await?;
856
857            debug!(
858                "Setup retry infrastructure for queue: {} with delayed exchange: {}",
859                options.queue_name, delayed_exchange_name
860            );
861        }
862
863        Ok(())
864    }
865}
866
867// Example message handler implementation
868pub struct SimpleMessageHandler<F, T>
869where
870    F: Fn(T, MessageContext) -> MessageResult + Send + Sync,
871    T: DeserializeOwned + Send + Sync,
872{
873    handler_fn: F,
874    _phantom: std::marker::PhantomData<T>,
875}
876
877impl<F, T> SimpleMessageHandler<F, T>
878where
879    F: Fn(T, MessageContext) -> MessageResult + Send + Sync + 'static,
880    T: DeserializeOwned + Send + Sync + 'static,
881{
882    pub fn new(handler_fn: F) -> Self {
883        Self {
884            handler_fn,
885            _phantom: std::marker::PhantomData,
886        }
887    }
888}
889
890#[async_trait]
891impl<F, T> MessageHandler<T> for SimpleMessageHandler<F, T>
892where
893    F: Fn(T, MessageContext) -> MessageResult + Send + Sync + 'static,
894    T: DeserializeOwned + Send + Sync + 'static,
895{
896    async fn handle(&self, message: T, context: MessageContext) -> MessageResult {
897        (self.handler_fn)(message, context)
898    }
899}
rust_rabbit/consumer.rs

rust_rabbit/
consumer.rs
