@asyncapi/java-spring-template NPM

AsyncAPI Java Spring Template

Java Spring template for the AsyncAPI Generator.

Attention, AsyncAPI v3 is not currently supported by this template

Usage

Install AsyncAPI CLI, for details follow the guide.

npm install -g @asyncapi/cli

Generate using CLI.

asyncapi generate fromTemplate <asyncapi.yaml> @asyncapi/java-spring-template

You can replace <asyncapi.yaml> with local path or URL pointing to any AsyncAPI document.

AsyncAPI definitions

To have correctly generated code, your AsyncAPI file MUST define operationId for every operation.

In order for the generator to know what names to use for some parameters AsyncAPI specification bindings SHOULD be used.

It is RECOMMENDED to not use anonymous objects in payload and components definition, if changing of data model is not possible, you MAY use $id to set name of element.

Complete example for Kafka is here. Notice information about binding.

channels:
  event.lighting.measured:
    publish:
      bindings:
        kafka:
          groupId: my-group
      message:
        $ref: '#/components/messages/lightMeasured'
    subscribe:
      message:
        $ref: '#/components/messages/lightMeasured'

Complete example for MQTT is here.

Supported parameters

Name	Description	Required	Default
disableEqualsHashCode	Disable generation of equals and hashCode methods for model classes.	No	`false`
inverseOperations	Generate an application that will publish messages to `publish` operation of channels and read messages from `subscribe` operation of channels. Literally this flag will simply swap `publish` and `subscribe` operations in the channels. This flag will be useful when you want to generate a code of mock for your main application. Be aware, generation could be incomplete and manual changes will be required e.g. if bindings are defined only for case of main application.	No	`false`
javaPackage	The Java package of the generated classes. Alternatively you can set the specification extension `info.x-java-package`. If both extension and parameter are used, parameter has more priority.	No	`com.asyncapi`
springBoot2	Generate template files for the Spring Boot version 2. For kafka protocol it will also force to use spring-kafka 2.9.9	No	`false`
maven	Generate pom.xml Maven build file instead of Gradle build.	No	`false`
listenerPollTimeout	Only for Kafka. Timeout in ms to use when polling the consumer.	No	`3000`
listenerConcurrency	Only for Kafka. Number of threads to run in the listener containers.	No	`3`
addTypeInfoHeader	Only for Kafka. Add type information to message header.	No	`true`
connectionTimeout	Only for MQTT. This value, measured in seconds, defines the maximum time interval the client will wait for the network connection to the MQTT server to be established. The default timeout is 30 seconds. A value of 0 disables timeout processing meaning the client will wait until the network connection is made successfully or fails.	No	`30`
disconnectionTimeout	Only for MQTT. The completion timeout in milliseconds when disconnecting. The default disconnect completion timeout is 5000 milliseconds.	No	`5000`
completionTimeout	Only for MQTT. The completion timeout in milliseconds for operations. The default completion timeout is 30000 milliseconds.	No	`30000`
mqttClientId	Only for MQTT. Provides the client identifier for the MQTT server. This parameter overrides the value of the clientId if it's set in the AsyncAPI file.If both aren't provided, a default value is set.	No
asyncapiFileDir	Path where original AsyncAPI file will be stored.	No	`src/main/resources/api/`

Examples

The shortest possible syntax:

asyncapi generate fromTemplate asyncapi.yaml @asyncapi/java-spring-template

Specify where to put the result with -o option and define parameter of poll timeout with -p option:

asyncapi generate fromTemplate asyncapi.yaml @asyncapi/java-spring-template -o ./src -p listenerPollTimeout=5000

Run it

Go to the root folder of the generated code and run this command (you need the JDK 17):

./gradlew bootRun

Development

Clone the repository:

git clone https://github.com/asyncapi/java-spring-template
cd java-spring-template

Download all template dependencies:
```
npm install
```
Make required changes in the template.
Run snapshot tests:
```
npm test
```
If there falling tests examine diff report and make an appropriate changes in template files or snapshots.
Check output generation project. Install AsyncAPI Generator:
```
npm install -g @asyncapi/cli
```

Run generation (assuming you are in template folder):

# for MQTT protocol test with below
asyncapi generate fromTemplate tests/mocks/mqtt.yml ./ -o output
# for Kafka protocol test with below
asyncapi generate fromTemplate tests/mocks/kafka.yml ./ -o output

Explore generated files in output directory. Generated project shouldn't contain syntax or compilation errors. Preferably generated tests should pass.

For local development, you need different variations of this command. First of all, you need to know about three important CLI flags:
--debug enables the debug mode.
--watch-template enables a watcher of changes that you make in the template. It regenerates your template whenever it detects a change.
--install enforces reinstallation of the template.

Missing features

See the list of features that are still missing in the component:

support of Kafka is done based on clear "spring-kafka" library without integration like for mqtt or amqp
generated code for protocol amqp could be out of date. Please have a look to application.yaml and AmqpConfig.java
tests for protocol amqp are not provided
parameters for topics are not supported
server variables are not entirely supported
security schemas are not supported
traits are not supported
Json serializer/deserializer is used always, without taking into account real content type
template generation of docker-compose depending on protocol of server, now the rabbitmq is hardcoded