Spring Cloud Stream supports general configuration options as well as configuration for bindings and binders. Some binders allow additional binding properties to support middleware-specific features.
Configuration options can be provided to Spring Cloud Stream applications via any mechanism supported by Spring Boot. This includes application arguments, environment variables, and YAML or .properties files.
The number of deployed instances of an application. Must be set for partitioning and if using Kafka.
Default: 1.
0 to instanceCount-1.
Used for partitioning and with Kafka.
Automatically set in Cloud Foundry to match the application’s instance index.A list of destinations that can be bound dynamically (for example, in a dynamic routing scenario). If set, only listed destinations can be bound.
Default: empty (allowing any destination to be bound).
Binding properties are supplied using the format spring.cloud.stream.bindings.<channelName>.<property>=<value>.
The <channelName> represents the name of the channel being configured (e.g., output for a Source).
In what follows, we indicate where we have omitted the spring.cloud.stream.bindings.<channelName>. prefix and focus just on the property name, with the understanding that the prefix will be included at runtime.
The following binding properties are available for both input and output bindings and
must be prefixed with spring.cloud.stream.bindings.<channelName>..
The consumer group of the channel. Applies only to inbound bindings. See Consumer Groups.
Default: null (indicating an anonymous consumer).
The content type of the channel. //See ???.
Default: null (so that no type coercion is performed).
The binder used by this binding. See Section 4.4, “Multiple Binders on the Classpath” for details.
Default: null (the default binder will be used, if one exists).
The following binding properties are available for input bindings only and must be prefixed with spring.cloud.stream.bindings.<channelName>.consumer..
The concurrency of the inbound consumer.
Default: 1.
Whether the consumer receives data from a partitioned producer.
Default: false.
When set to raw, disables header parsing on input.
Effective only for messaging middleware that does not support message headers natively and requires header embedding.
Useful when inbound data is coming from outside Spring Cloud Stream applications.
Default: embeddedHeaders.
The number of attempts of re-processing an inbound message. Currently ignored by Kafka.
Default: 3.
The backoff initial interval on retry. Currently ignored by Kafka.
Default: 1000.
The maximum backoff interval. Currently ignored by Kafka.
Default: 10000.
The backoff multiplier.
Default: 2.0.
The following binding properties are available for output bindings only and must be prefixed with spring.cloud.stream.bindings.<channelName>.producer..
A SpEL expression that determines how to partition outbound data.
If set, or if partitionKeyExtractorClass is set, outbound data on this channel will be partitioned, and partitionCount must be set to a value greater than 1 to be effective.
The two options are mutually exclusive.
See Section 2.5, “Partitioning Support”.
Default: null.
A PartitionKeyExtractorStrategy implementation.
If set, or if partitionKeyExpression is set, outbound data on this channel will be partitioned, and partitionCount must be set to a value greater than 1 to be effective.
The two options are mutually exclusive.
See Section 2.5, “Partitioning Support”.
Default: null.
A PartitionSelectorStrategy implementation.
Mutually exclusive with partitionSelectorExpression.
If neither is set, the partition will be selected as the hashCode(key) % partitionCount, where key is computed via either partitionKeyExpression or partitionKeyExtractorClass.
Default: null.
A SpEL expression for customizing partition selection.
Mutually exclusive with partitionSelectorClass.
If neither is set, the partition will be selected as the hashCode(key) % partitionCount, where key is computed via either partitionKeyExpression or partitionKeyExtractorClass.
Default: null.
The number of target partitions for the data, if partitioning is enabled. Must be set to a value greater than 1 if the producer is partitioned. On Kafka, interpreted as a hint; the larger of this and the partition count of the target topic is used instead.
Default: 1.
When set to raw, disables header embedding on output.
Effective only for messaging middleware that does not support message headers natively and requires header embedding.
Useful when producing data for non-Spring Cloud Stream applications.
Default: embeddedHeaders.