fix(inputs.amqp_consumer): Avoid deprecations when handling defaults (#12818)

plugins/inputs/amqp_consumer/amqp_consumer.go

@@ -23,10 +23,6 @@ import (
 //go:embed sample.conf
 var sampleConfig string
 
-const (
-	defaultMaxUndeliveredMessages = 1000
-)
-
 type empty struct{}
 type semaphore chan empty
 
@@ -80,23 +76,46 @@ func (a *externalAuth) Response() string {
 	return "\000"
 }
 
-const (
-	DefaultAuthMethod = "PLAIN"
-
-	DefaultBroker = "amqp://localhost:5672/influxdb"
-
-	DefaultExchangeType       = "topic"
-	DefaultExchangeDurability = "durable"
-
-	DefaultQueueDurability = "durable"
-
-	DefaultPrefetchCount = 50
-)
-
 func (*AMQPConsumer) SampleConfig() string {
 	return sampleConfig
 }
 
+func (a *AMQPConsumer) Init() error {
+	// Defaults
+	if a.URL != "" {
+		a.Brokers = append(a.Brokers, a.URL)
+	}
+	if len(a.Brokers) == 0 {
+		a.Brokers = []string{"amqp://localhost:5672/influxdb"}
+	}
+
+	if a.AuthMethod == "" {
+		a.AuthMethod = "PLAIN"
+	}
+
+	if a.ExchangeType == "" {
+		a.ExchangeType = "topic"
+	}
+
+	if a.ExchangeDurability == "" {
+		a.ExchangeDurability = "durable"
+	}
+
+	if a.QueueDurability == "" {
+		a.QueueDurability = "durable"
+	}
+
+	if a.PrefetchCount == 0 {
+		a.PrefetchCount = 50
+	}
+
+	if a.MaxUndeliveredMessages == 0 {
+		a.MaxUndeliveredMessages = 1000
+	}
+
+	return nil
+}
+
 func (a *AMQPConsumer) SetParser(parser parsers.Parser) {
 	a.parser = parser
 }
@@ -190,9 +209,6 @@ func (a *AMQPConsumer) Start(acc telegraf.Accumulator) error {
 
 func (a *AMQPConsumer) connect(amqpConf *amqp.Config) (<-chan amqp.Delivery, error) {
 	brokers := a.Brokers
-	if len(brokers) == 0 {
-		brokers = []string{a.URL}
-	}
 
 	p := rand.Perm(len(brokers))
 	for _, n := range p {
@@ -454,14 +470,6 @@ func (a *AMQPConsumer) Stop() {
 
 func init() {
 	inputs.Add("amqp_consumer", func() telegraf.Input {
-		return &AMQPConsumer{
+		return &AMQPConsumer{}
-			URL:                    DefaultBroker,
-			AuthMethod:             DefaultAuthMethod,
-			ExchangeType:           DefaultExchangeType,
-			ExchangeDurability:     DefaultExchangeDurability,
-			QueueDurability:        DefaultQueueDurability,
-			PrefetchCount:          DefaultPrefetchCount,
-			MaxUndeliveredMessages: defaultMaxUndeliveredMessages,
-		}
 	})
 }