From bc434fde5cb401f131fc58971d4ac93fffd9a877 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Christian=20K=C3=B6hn?= <christian.koehn@finleap.com>
Date: Fri, 16 Jul 2021 09:54:38 +0200
Subject: [PATCH] Add option to skip exchange declaration

---
 consume.go         | 27 +++++++++++++++------------
 consume_options.go |  9 +++++++++
 2 files changed, 24 insertions(+), 12 deletions(-)

diff --git a/consume.go b/consume.go
index ee393ff..37e828a 100644
--- a/consume.go
+++ b/consume.go
@@ -2,8 +2,9 @@ package rabbitmq
 
 import (
 	"fmt"
-	"github.com/streadway/amqp"
 	"time"
+
+	"github.com/streadway/amqp"
 )
 
 // Consumer allows you to create and connect to queues for data consumption.
@@ -188,17 +189,19 @@ func (consumer Consumer) startGoroutines(
 		if exchange.Name == "" {
 			return fmt.Errorf("binding to exchange but name not specified")
 		}
-		err = consumer.chManager.channel.ExchangeDeclare(
-			exchange.Name,
-			exchange.Kind,
-			exchange.Durable,
-			exchange.AutoDelete,
-			exchange.Internal,
-			exchange.NoWait,
-			tableToAMQPTable(exchange.ExchangeArgs),
-		)
-		if err != nil {
-			return err
+		if exchange.Declare {
+			err = consumer.chManager.channel.ExchangeDeclare(
+				exchange.Name,
+				exchange.Kind,
+				exchange.Durable,
+				exchange.AutoDelete,
+				exchange.Internal,
+				exchange.NoWait,
+				tableToAMQPTable(exchange.ExchangeArgs),
+			)
+			if err != nil {
+				return err
+			}
 		}
 		for _, routingKey := range routingKeys {
 			err = consumer.chManager.channel.QueueBind(
diff --git a/consume_options.go b/consume_options.go
index e8eb1bb..e0f8a3b 100644
--- a/consume_options.go
+++ b/consume_options.go
@@ -55,6 +55,7 @@ func getBindingExchangeOptionsOrSetDefault(options *ConsumeOptions) *BindingExch
 			Internal:     false,
 			NoWait:       false,
 			ExchangeArgs: nil,
+			Declare:      true,
 		}
 	}
 	return options.BindingExchange
@@ -70,6 +71,7 @@ type BindingExchangeOptions struct {
 	Internal     bool
 	NoWait       bool
 	ExchangeArgs Table
+	Declare      bool
 }
 
 // WithConsumeOptionsQueueDurable sets the queue to durable, which means it won't
@@ -151,6 +153,13 @@ func WithConsumeOptionsBindingExchangeArgs(args Table) func(*ConsumeOptions) {
 	}
 }
 
+// WithConsumeOptionsBindingExchangeSkipDeclare returns a function that skips the declaration of the
+// binding exchange. Use this setting if the exchange already exists and you don't need to declare
+// it on consumer start.
+func WithConsumeOptionsBindingExchangeSkipDeclare(options *ConsumeOptions) {
+	getBindingExchangeOptionsOrSetDefault(options).Declare = false
+}
+
 // WithConsumeOptionsBindingNoWait sets the bindings to nowait, which means if the queue can not be bound
 // the channel will not be closed with an error.
 func WithConsumeOptionsBindingNoWait(options *ConsumeOptions) {