Configuration

Configuration is loaded from the queue: section of application.yaml. Unlike most extension packages, QueueConfig is passed explicitly to QueueModule.configure(config) rather than auto-injected via config_key.

Env-Var Prefix

All keys can be overridden with environment variables using the prefix LEX_QUEUE__:

LEX_QUEUE__BACKENDS__0__DRIVER=redis \
LEX_QUEUE__BACKENDS__0__NAME=cache \
LEX_QUEUE__BACKENDS__0__PRIMARY=true \
LEX_QUEUE__BACKENDS__0__REDIS__URL=redis://localhost:6379/0

Top Level: QueueConfig

Key	Type	Default	Description
backends	list[NamedQueueConfig]	[]	Named queue backend declarations

NamedQueueConfig

Key	Type	Default	Description
name	str	(required)	Unique backend ID, used as Named() DI key
primary	bool	False	Also register under unnamed QueueProtocol binding
driver	str	"memory"	Backend driver: memory, redis, rabbitmq, kafka, sqs, azure_servicebus, gcp_pubsub
delivery_guarantee	str	"at_least_once"	Delivery semantics
max_retries	int	3	Max retries before DLQ routing
redis	RedisDriverConfig | None	None	Redis-specific settings
rabbitmq	RabbitMQDriverConfig | None	None	RabbitMQ-specific settings
kafka	KafkaDriverConfig | None	None	Kafka-specific settings
sqs	SQSDriverConfig | None	None	SQS-specific settings
azure_servicebus	AzureServiceBusDriverConfig | None	None	Azure Service Bus settings
gcp_pubsub	GCPPubSubDriverConfig | None	None	GCP Pub/Sub settings

Driver Configs

RedisDriverConfig

Key	Type	Default	Description
url	str | None	None	Redis URL (redis://host:port/db)
max_connections	int	10	Connection pool size
socket_timeout	float	5.0	Socket timeout in seconds

RabbitMQDriverConfig

Key	Type	Default	Description
url	str | None	None	AMQP URL (amqp://user:pass@host/)
exchange	str	"lexigram"	Exchange name
prefetch_count	int	10	Consumer prefetch count

KafkaDriverConfig

Key	Type	Default	Description
bootstrap_servers	str | None	None	Kafka broker(s) (host:port,host:port)
client_id	str	"lexigram"	Client ID
group_id	str	"lexigram-consumers"	Consumer group ID
auto_offset_reset	str	"latest"	Offset reset: earliest or latest

SQSDriverConfig

Key	Type	Default	Description
region	str	"us-east-1"	AWS region
queue_url	str | None	None	SQS queue URL
visibility_timeout	int	30	Visibility timeout in seconds

AzureServiceBusDriverConfig

Key	Type	Default	Description
connection_str	str | None	None	Service Bus connection string
queue_name	str	""	Queue name
max_message_count	int	10	Max messages per receive call
max_wait_time	float	5.0	Max wait per receive call (seconds)

GCPPubSubDriverConfig

Key	Type	Default	Description
project_id	str | None	None	GCP project ID
topic_id	str	""	Pub/Sub topic ID
subscription_id	str	""	Subscription ID for consuming
max_messages	int	10	Max messages per pull call
max_wait_time	float	5.0	gRPC pull timeout (seconds)

Minimal YAML Example

queue:
  backends:
    - name: default
      driver: memory
      primary: true

Multi-Backend YAML Example

queue:
  backends:
    - name: notifications
      driver: redis
      primary: true
      max_retries: 5
      redis:
        url: "redis://localhost:6379/1"
        max_connections: 20

    - name: events
      driver: kafka
      delivery_guarantee: at_least_once
      kafka:
        bootstrap_servers: "localhost:9092,localhost:9093"
        group_id: order-consumers
        auto_offset_reset: earliest

    - name: audit
      driver: sqs
      sqs:
        region: us-west-2
        queue_url: "https://sqs.us-west-2.amazonaws.com/123456789/audit"

Env-Var Form

LEX_QUEUE__BACKENDS__0__NAME=default \
LEX_QUEUE__BACKENDS__0__DRIVER=redis \
LEX_QUEUE__BACKENDS__0__PRIMARY=true \
LEX_QUEUE__BACKENDS__0__MAX_RETRIES=5 \
LEX_QUEUE__BACKENDS__0__REDIS__URL=redis://localhost:6379/1 \
LEX_QUEUE__BACKENDS__0__REDIS__MAX_CONNECTIONS=20