Add Cloud Events support to Spring Integration #10448

cppwfs · 2025-09-26T20:28:11Z

Introduces Cloud Events v1.0 specification support including message converters, transformers, and utilities.

Key components added:

CloudEventMessageConverter for message format conversion
ToCloudEventTransformer for transforming messages to Cloud Events
MessageBinaryMessageReader/Writer for binary format handling
CloudEventProperties for configuration management
Header pattern matching utilities for flexible event mapping
Add reference docs and what's-new paragraph

Introduces Cloud Events v1.0 specification support including message converters, transformers, and utilities. Key components added: - CloudEventMessageConverter for message format conversion - ToCloudEventTransformer for transforming messages to Cloud Events - MessageBinaryMessageReader/Writer for binary format handling - CloudEventProperties for configuration management - Header pattern matching utilities for flexible event mapping - Add reference docs and what's-new paragraph

artembilan

Left some at a glance review.

Thank you!

artembilan · 2025-09-26T21:25:59Z

build.gradle

 }

+project('spring-integration-cloudevents') {
+    description = 'Spring Integration Cloud Events Support'


CloudEvents ?

artembilan · 2025-09-26T21:27:12Z

build.gradle

+        }
+        optionalApi "org.apache.avro:avro:$avroVersion"
+        optionalApi "io.cloudevents:cloudevents-xml:$cloudEventsVersion"
+        optionalApi 'org.jspecify:jspecify'


I don't think this is something we need to specify manually.
It has to come from Spring Core.

artembilan · 2025-09-26T21:28:09Z

build.gradle

+            exclude group: 'org.apache.avro', module: 'avro'
+        }
+        optionalApi "org.apache.avro:avro:$avroVersion"
+        optionalApi "io.cloudevents:cloudevents-xml:$cloudEventsVersion"


Are these all optional deps really necessary for our production code?
Maybe test scope instead?

artembilan · 2025-09-26T21:28:31Z

build.gradle

+        optionalApi "io.cloudevents:cloudevents-xml:$cloudEventsVersion"
+        optionalApi 'org.jspecify:jspecify'
+
+        testImplementation 'org.springframework.amqp:spring-rabbit-test'


Do we really need to test this stuff against RabbitMQ ?

artembilan · 2025-09-26T21:29:31Z

...src/main/java/org/springframework/integration/cloudevents/v1/CloudEventMessageConverter.java

+ * limitations under the License.
+ */
+
+package org.springframework.integration.cloudevents.v1;


I don't think we need a specific v1 package.
How about just aim for v1 as is in the root package?

artembilan · 2025-09-26T21:30:09Z

...src/main/java/org/springframework/integration/cloudevents/v1/CloudEventMessageConverter.java

+ */
+public class CloudEventMessageConverter implements MessageConverter {
+
+	private String cePrefix;


artembilan · 2025-09-26T21:31:32Z

...src/main/java/org/springframework/integration/cloudevents/v1/CloudEventMessageConverter.java

+
+	@Override
+	public Object fromMessage(Message<?> message, Class<?> targetClass) {
+		Assert.state(CloudEvent.class.isAssignableFrom(targetClass), "Target class must be a CloudEvent");


I think we can just ignore the class and state that in the Javadocs.

artembilan · 2025-09-26T21:32:48Z

...g/springframework/integration/cloudevents/v1/transformer/CloudEventMessageConverterTest.java

+import static org.assertj.core.api.Assertions.assertThatIllegalStateException;
+import static org.assertj.core.api.Assertions.catchIllegalStateException;
+
+public class CloudEventMessageConverterTest {


..Tests, please.

artembilan · 2025-09-26T21:33:45Z

src/reference/antora/modules/ROOT/pages/whats-new.adoc

+
+[[x7.0-cloudevents]]
+=== CloudEvents
+The CloudEvent transformer converts Spring Integration messages into CloudEvent compliant messages.


Blank line after title.

artembilan · 2025-09-26T21:34:05Z

src/reference/antora/modules/ROOT/pages/whats-new.adoc

+=== CloudEvents
+The CloudEvent transformer converts Spring Integration messages into CloudEvent compliant messages.
+This transformer provides  support for the CloudEvents specification v1.0 with configurable output formats, header pattern matching, and extension management.
+See xref:cloudevents/cloudevents-transform.adoc[] for more information.


Why it cannot be just top-level cloudevents.adoc ?

artembilan

Sorry for a lengthy review and some doubts I've expressed.

I addition, what are your thoughts about content of this package in Spring Cloud Function: https://github.com/spring-cloud/spring-cloud-function/tree/main/spring-cloud-function-context/src/main/java/org/springframework/cloud/function/cloudevent ?

I mean transformer does the trick indeed, but only from an integration flow context.
How about the way to be able to construct CloudEvent programmatically?
Or just existing SDK API is enough to deal with?

artembilan · 2025-09-29T13:55:13Z

...src/main/java/org/springframework/integration/cloudevents/v1/CloudEventMessageConverter.java

+		return CloudEventUtils.toReader((CloudEvent) payload).read(new MessageBuilderMessageWriter(headers, this.cePrefix));
+	}
+
+	private MessageReader createMessageReader(Message<?> message) {


Looks like all of methods starting with this has to be static.

artembilan · 2025-09-29T13:55:32Z

...src/main/java/org/springframework/integration/cloudevents/v1/CloudEventMessageConverter.java

+		if (message.containsKey(CloudEventsHeaders.SPEC_VERSION)) {
+			return message.get(CloudEventsHeaders.SPEC_VERSION).toString();
+		}
+		return null;


Looks like @Nullability is not a part of this package yet.

artembilan · 2025-09-29T13:57:25Z

...src/main/java/org/springframework/integration/cloudevents/v1/MessageBinaryMessageReader.java

+ *
+ */
+public class MessageBinaryMessageReader extends BaseGenericBinaryMessageReaderImpl<String, Object> {
+	private final String cePrefix;


Every member of the class has to be surrounded with blank lines.

artembilan · 2025-09-29T14:04:54Z

...pringframework/integration/cloudevents/v1/transformer/ToCloudEventTransformerExtensions.java

+	public ToCloudEventTransformerExtensions(MessageHeaders headers, @Nullable String patterns) {
+		this.cloudEventExtensions = new HashMap<>();
+		headers.keySet().forEach(key -> {
+			Boolean result = HeaderPatternMatcher.categorizeHeader(key, patterns);


I don't think we need this logic here.
We can perform filtering (and categorization) only once in the transformer.
And then push into this extensions only those headers which are really extensions.

From there I don't think it makes sense to make this class as public

artembilan · 2025-09-29T14:06:47Z

...a/org/springframework/integration/cloudevents/v1/transformer/utils/HeaderPatternMatcher.java

+ *
+ * @since 7.0
+ */
+public final class HeaderPatternMatcher {


This class is fully redundant.
Make the pattern property of the transformer as String @Nullable... patterns

artembilan · 2025-09-29T14:10:12Z

...java/org/springframework/integration/cloudevents/v1/transformer/ToCloudEventTransformer.java

+	private Message<String> convertToJsonMessage(CloudEvent cloudEvent, MessageHeaders originalHeaders) {
+		JsonFormat jsonFormat = new JsonFormat();
+		String jsonContent = new String(jsonFormat.serialize(cloudEvent));
+		return buildStringMessage(jsonContent, originalHeaders, "application/json");


Why do we have to convert to String?
Why just byte[] for serialized XML/JSON is not enough?

artembilan · 2025-09-29T14:14:06Z

...java/org/springframework/integration/cloudevents/v1/transformer/ToCloudEventTransformer.java

+
+	@Override
+	public String getComponentType() {
+		return "to-cloud-transformer";


Since this is not in a core module any more, the type has to come with prefix.
So, I believe this one should be like: ce:to-cloudevents-transformer

artembilan · 2025-09-29T14:17:43Z

...in/java/org/springframework/integration/cloudevents/v1/transformer/CloudEventProperties.java

+ *
+ * @since 7.0
+ */
+public class CloudEventProperties {


I'm not sure in this class.
Why all these properties cannot be on the transformer itself?
More over: how about expressions against the request message to determine all these options at runtime?
I think I had expressions in my original PoC: #3246.

artembilan · 2025-09-29T14:20:48Z

...devents/src/main/java/org/springframework/integration/cloudevents/v1/CloudEventsHeaders.java

+ *
+ * @since 7.0
+ */
+public final class CloudEventsHeaders {


I'm not very convinced that we need this class at all.
Especially with the case when we can change the prefix.

artembilan · 2025-09-29T14:23:37Z

src/reference/antora/modules/ROOT/pages/cloudevents/cloudevents-transform.adoc

+
+[[cloudevent-transformer-conversion-default]]
+==== DEFAULT
+The default format produces standard CloudEvent messages using Spring's CloudEvent support.


Blank like after section title.

cppwfs requested a review from artembilan September 26, 2025 20:28

cppwfs force-pushed the SI-cloud-events branch from b377397 to 03d1f51 Compare September 26, 2025 20:36

cppwfs force-pushed the SI-cloud-events branch from 03d1f51 to 02a1329 Compare September 26, 2025 20:47

artembilan requested changes Sep 26, 2025

View reviewed changes

artembilan requested changes Sep 29, 2025

View reviewed changes

Add Cloud Events support to Spring Integration #10448

Are you sure you want to change the base?

Add Cloud Events support to Spring Integration #10448

Uh oh!

Conversation

cppwfs commented Sep 26, 2025

Uh oh!

artembilan left a comment

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

artembilan left a comment

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Uh oh!