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INT-4401: Document working with shaded jars

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JIRA: https://jira.spring.io/browse/INT-4401

How to fix up the `spring.factories` etc.

* Polishing
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Gary Russell
2018-02-13 16:19:15 -05:00
committed by Artem Bilan
parent eaa19c8ddb
commit a4130c9e59
1 changed files with 80 additions and 0 deletions
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src/reference/asciidoc/overview.adoc
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@@ -273,6 +273,86 @@ If you need to send a messages during startup, implement `ApplicationListener` a
Alternatively, implement `SmartLifecycle`, put your bean in a late phase, and send the messages from the `start()` method.
[[shaded]]
=== Considerations When using Packaged (e.g. Shaded) Jars
Spring Integration bootstraps certain features using Spring Framework's `SpringFactories` mechanism to load several `IntegrationConfigurationInitializer` classes.
This includes the `-core` jar as well as certain others such as `-http`, `-jmx`, etc.
The information for this process is stored in a file `META-INF/spring.factories` in each jar.
Some developers prefer to repackage their application and all dependencies into a single jar using well-known tools, such as the https://maven.apache.org/plugins/maven-shade-plugin/[Apache Maven Shade Plugin].
By default, the shade plugin will not merge the `spring.factories` files when producing the shaded jar.
In addition to `spring.factories`, there are other `META-INF` files (`spring.handlers`, `spring.schemas`) used for XML configuration.
These also need to be merged.
IMPORTANT: https://docs.spring.io/spring-boot/docs/current/reference/html/executable-jar.html[Spring Boot's executable jar mechanism] takes a different approach in that it nests the jars, thus retaining each `spring.factories` file on the class path.
So, with a Spring Boot application, nothing more is needed, if you use its default executable jar format.
Even if you are not using Spring Boot, you can still use tooling provided by Boot to enhance the shade plugin by adding transformers for the above mentioned files.
The following is an example configuration for the plugin at the time of writing.
You may wish to consult the current https://github.com/spring-projects/spring-boot/blob/master/spring-boot-project/spring-boot-starters/spring-boot-starter-parent/pom.xml[spring-boot-starter-parent pom] to see the current settings that boot uses.
.pom.xml
[source, xml]
----
...
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-shade-plugin</artifactId>
<configuration>
<keepDependenciesWithProvidedScope>true</keepDependenciesWithProvidedScope>
<createDependencyReducedPom>true</createDependencyReducedPom>
</configuration>
<dependencies>
<dependency> <1>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
<version>${spring.boot.version}</version>
</dependency>
</dependencies>
<executions>
<execution>
<phase>package</phase>
<goals>
<goal>shade</goal>
</goals>
<configuration>
<transformers> <2>
<transformer
implementation="org.apache.maven.plugins.shade.resource.AppendingTransformer">
<resource>META-INF/spring.handlers</resource>
</transformer>
<transformer
implementation="org.springframework.boot.maven.PropertiesMergingResourceTransformer">
<resource>META-INF/spring.factories</resource>
</transformer>
<transformer
implementation="org.apache.maven.plugins.shade.resource.AppendingTransformer">
<resource>META-INF/spring.schemas</resource>
</transformer>
<transformer
implementation="org.apache.maven.plugins.shade.resource.ServicesResourceTransformer" />
</transformers>
</configuration>
</execution>
</executions>
</plugin>
</plugins>
...
----
Specifically,
<1> add the `spring-boot-maven-plugin` as a dependency
<2> configure the transformers
Add a property for `${spring.boot.version}` or use a version explicitly there.
[[programming-tips]]
=== Programming Tips and Tricks