e71cf28c1a
This commit adds a default, empty suppression configuration file needed to set up Checkstyle. Resolves #463
200 lines
8.2 KiB
Plaintext
200 lines
8.2 KiB
Plaintext
////
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DO NOT EDIT THIS FILE. IT WAS GENERATED.
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Manual changes to this file will be lost when it is generated again.
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Edit the files in the src/main/asciidoc/ directory instead.
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////
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:branch: master
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image::https://travis-ci.org/spring-cloud/spring-cloud-function.svg?branch={branch}[Build Status, link=https://travis-ci.org/spring-cloud/spring-cloud-function]
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== Introduction
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Spring Cloud Function is a project with the following high-level goals:
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* Promote the implementation of business logic via functions.
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* Decouple the development lifecycle of business logic from any specific runtime target so that the same code can run as a web endpoint, a stream processor, or a task.
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* Support a uniform programming model across serverless providers, as well as the ability to run standalone (locally or in a PaaS).
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* Enable Spring Boot features (auto-configuration, dependency injection, metrics) on serverless providers.
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It abstracts away all of the transport details and
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infrastructure, allowing the developer to keep all the familiar tools
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and processes, and focus firmly on business logic.
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Here's a complete, executable, testable Spring Boot application
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(implementing a simple string manipulation):
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[source,java]
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----
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@SpringBootApplication
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public class Application {
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@Bean
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public Function<Flux<String>, Flux<String>> uppercase() {
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return flux -> flux.map(value -> value.toUpperCase());
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}
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public static void main(String[] args) {
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SpringApplication.run(Application.class, args);
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}
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}
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----
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It's just a Spring Boot application, so it can be built, run and
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tested, locally and in a CI build, the same way as any other Spring
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Boot application. The `Function` is from `java.util` and `Flux` is a
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https://www.reactive-streams.org/[Reactive Streams] `Publisher` from
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https://projectreactor.io/[Project Reactor]. The function can be
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accessed over HTTP or messaging.
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Spring Cloud Function has 4 main features:
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In the nutshell Spring Cloud Function provides the following features:
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1. Wrappers for `@Beans` of type `Function`, `Consumer` and
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`Supplier`, exposing them to the outside world as either HTTP
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endpoints and/or message stream listeners/publishers with RabbitMQ, Kafka etc.
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* _Choice of programming styles - reactive, imperative or hybrid._
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* _Function composition and adaptation (e.g., composing imperative functions with reactive)._
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* _Support for reactive function with multiple inputs and outputs allowing merging, joining and other complex streaming operation to be handled by functions._
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* _Transparent type conversion of inputs and outputs._
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* _Packaging functions for deployments, specific to the target platform (e.g., Project Riff, AWS Lambda and more)_
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* _Adapters to expose function to the outside world as HTTP endpoints etc._
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* _Deploying a JAR file containing such an application context with an isolated classloader, so that you can pack them together in a single JVM._
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* _Compiling strings which are Java function bodies into bytecode, and then turning them into `@Beans` that can be wrapped as above._
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* _Adapters for https://github.com/spring-cloud/spring-cloud-function/tree/master/spring-cloud-function-adapters/spring-cloud-function-adapter-aws[AWS Lambda], https://github.com/spring-cloud/spring-cloud-function/tree/master/spring-cloud-function-adapters/spring-cloud-function-adapter-azure[Azure], https://github.com/spring-cloud/spring-cloud-function/tree/master/spring-cloud-function-adapters/spring-cloud-function-adapter-openwhisk[Apache OpenWhisk] and possibly other "serverless" service providers._
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== Getting Started
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Build from the command line (and "install" the samples):
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----
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$ ./mvnw clean install
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----
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(If you like to YOLO add `-DskipTests`.)
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Run one of the samples, e.g.
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----
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$ java -jar spring-cloud-function-samples/function-sample/target/*.jar
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----
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This runs the app and exposes its functions over HTTP, so you can
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convert a string to uppercase, like this:
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----
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$ curl -H "Content-Type: text/plain" localhost:8080/uppercase -d Hello
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HELLO
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----
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You can convert multiple strings (a `Flux<String>`) by separating them
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with new lines
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----
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$ curl -H "Content-Type: text/plain" localhost:8080/uppercase -d 'Hello
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> World'
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HELLOWORLD
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----
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(You can use `^Q^J` in a terminal to insert a new line in a literal
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string like that.)
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== Building
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:jdkversion: 1.7
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=== Basic Compile and Test
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To build the source you will need to install JDK {jdkversion}.
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Spring Cloud uses Maven for most build-related activities, and you
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should be able to get off the ground quite quickly by cloning the
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project you are interested in and typing
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----
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$ ./mvnw install
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----
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NOTE: You can also install Maven (>=3.3.3) yourself and run the `mvn` command
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in place of `./mvnw` in the examples below. If you do that you also
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might need to add `-P spring` if your local Maven settings do not
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contain repository declarations for spring pre-release artifacts.
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NOTE: Be aware that you might need to increase the amount of memory
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available to Maven by setting a `MAVEN_OPTS` environment variable with
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a value like `-Xmx512m -XX:MaxPermSize=128m`. We try to cover this in
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the `.mvn` configuration, so if you find you have to do it to make a
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build succeed, please raise a ticket to get the settings added to
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source control.
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For hints on how to build the project look in `.travis.yml` if there
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is one. There should be a "script" and maybe "install" command. Also
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look at the "services" section to see if any services need to be
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running locally (e.g. mongo or rabbit). Ignore the git-related bits
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that you might find in "before_install" since they're related to setting git
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credentials and you already have those.
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The projects that require middleware generally include a
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`docker-compose.yml`, so consider using
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https://docs.docker.com/compose/[Docker Compose] to run the middeware servers
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in Docker containers. See the README in the
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https://github.com/spring-cloud-samples/scripts[scripts demo
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repository] for specific instructions about the common cases of mongo,
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rabbit and redis.
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NOTE: If all else fails, build with the command from `.travis.yml` (usually
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`./mvnw install`).
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=== Documentation
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The spring-cloud-build module has a "docs" profile, and if you switch
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that on it will try to build asciidoc sources from
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`src/main/asciidoc`. As part of that process it will look for a
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`README.adoc` and process it by loading all the includes, but not
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parsing or rendering it, just copying it to `${main.basedir}`
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(defaults to `${basedir}`, i.e. the root of the project). If there are
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any changes in the README it will then show up after a Maven build as
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a modified file in the correct place. Just commit it and push the change.
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=== Working with the code
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If you don't have an IDE preference we would recommend that you use
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https://www.springsource.com/developer/sts[Spring Tools Suite] or
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https://eclipse.org[Eclipse] when working with the code. We use the
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https://eclipse.org/m2e/[m2eclipse] eclipse plugin for maven support. Other IDEs and tools
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should also work without issue as long as they use Maven 3.3.3 or better.
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==== Importing into eclipse with m2eclipse
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We recommend the https://eclipse.org/m2e/[m2eclipse] eclipse plugin when working with
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eclipse. If you don't already have m2eclipse installed it is available from the "eclipse
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marketplace".
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NOTE: Older versions of m2e do not support Maven 3.3, so once the
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projects are imported into Eclipse you will also need to tell
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m2eclipse to use the right profile for the projects. If you
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see many different errors related to the POMs in the projects, check
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that you have an up to date installation. If you can't upgrade m2e,
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add the "spring" profile to your `settings.xml`. Alternatively you can
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copy the repository settings from the "spring" profile of the parent
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pom into your `settings.xml`.
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==== Importing into eclipse without m2eclipse
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If you prefer not to use m2eclipse you can generate eclipse project metadata using the
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following command:
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[indent=0]
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----
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$ ./mvnw eclipse:eclipse
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----
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The generated eclipse projects can be imported by selecting `import existing projects`
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from the `file` menu.
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== Contributing
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:spring-cloud-build-branch: master
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Please refer to https://github.com/spring-cloud/spring-cloud-build#contributing[this Spring Cloud documentation]
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to learn more about the licensing, Contributor License Agreement, Code of Conduct, Code Conventions and Checkstyle Configuration.
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