spring-cloud-zookeeper

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image::https://travis-ci.org/spring-cloud/spring-cloud-zookeeper.svg?branch=master[Build Status, link=https://travis-ci.org/spring-cloud/spring-cloud-zookeeper]

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:sc-ext: java
:project-full-name: Spring Cloud Zookeeper

This project provides Zookeeper integrations for Spring Boot applications through
autoconfiguration and binding to the Spring Environment and other Spring programming model
idioms. With a few annotations, you can quickly enable and configure the common patterns
inside your application and build large distributed systems with Zookeeper based
components. The provided patterns include Service Discovery and Configuration. Integration
with Spring Cloud Netflix provides Intelligent Routing (Zuul), Client Side Load Balancing
(Ribbon), and Circuit Breaker (Hystrix).

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:sc-ext: java
:project-full-name: Spring Cloud Zookeeper

== Zookeeper overview

ZooKeeper is a centralized service for maintaining configuration information, naming,
providing distributed synchronization, and providing group services. See the
https://zookeeper.apache.org[Zookeeper site] for more information. Spring Cloud Zookeeper
also builds on the https://curator.apache.org[Apache Curator] project, which started life
at Netflix.

== Spring Cloud Zookeeper Features

Spring Cloud Zookeeper includes the following features:

• Spring Cloud DiscoveryClient implementation (supports Ribbon and Zuul)
• Zookeeper-based PropertySource loaded during the 'bootstrap' phase

== Running the Sample

. https://zookeeper.apache.org/doc/current/zookeeperStarted.html#sc_Download[Install
zookeeper] (On a mac with homebrew, use brew install zookeeper).
. https://zookeeper.apache.org/doc/current/zookeeperStarted.html#sc_InstallingSingleMode[Start
zookeeper].
. https://zookeeper.apache.org/doc/current/zookeeperStarted.html#sc_ConnectingToZooKeeper[Verify
zookeeper is running].
. Run mvn --settings .settings.xml package.
Doing so brings in the required Spring Cloud Maven repositories and Build.
. Run java -jar spring-cloud-zookeeper-sample/target/spring-cloud-zookeeper-sample-1.2.0.BUILD-SNAPSHOT.jar.
. Visit http://localhost:8080 to verify that {"serviceId":"testZookeeperApp","host":"<yourhost>","port":8080} works.
. Run java -jar spring-cloud-zookeeper-sample/target/spring-cloud-zookeeper-sample-1.2.0.BUILD-SNAPSHOT.jar --server.port=8081
. Visit http://localhost:8080 again to verify that {"serviceId":"testZookeeperApp","host":"<yourhost>","port":8081} eventually shows up in the results in a round-robin fashion. (It may take a minute or so.)

== Building

:jdkversion: 1.7

=== Basic Compile and Test

To build the source you will need to install JDK {jdkversion}.

Spring Cloud uses Maven for most build-related activities, and you
should be able to get off the ground quite quickly by cloning the
project you are interested in and typing

$ ./mvnw install

NOTE: You can also install Maven (>=3.3.3) yourself and run the mvn command
in place of ./mvnw in the examples below. If you do that you also
might need to add -P spring if your local Maven settings do not
contain repository declarations for spring pre-release artifacts.

NOTE: Be aware that you might need to increase the amount of memory
available to Maven by setting a MAVEN_OPTS environment variable with
a value like -Xmx512m -XX:MaxPermSize=128m. We try to cover this in
the .mvn configuration, so if you find you have to do it to make a
build succeed, please raise a ticket to get the settings added to
source control.

For hints on how to build the project look in .travis.yml if there
is one. There should be a "script" and maybe "install" command. Also
look at the "services" section to see if any services need to be
running locally (e.g. mongo or rabbit). Ignore the git-related bits
that you might find in "before_install" since they're related to setting git
credentials and you already have those.

The projects that require middleware generally include a
docker-compose.yml, so consider using
https://docs.docker.com/compose/[Docker Compose] to run the middeware servers
in Docker containers. See the README in the
https://github.com/spring-cloud-samples/scripts[scripts demo
repository] for specific instructions about the common cases of mongo,
rabbit and redis.

NOTE: If all else fails, build with the command from .travis.yml (usually
./mvnw install).

=== Documentation

The spring-cloud-build module has a "docs" profile, and if you switch
that on it will try to build asciidoc sources from
src/main/asciidoc. As part of that process it will look for a
README.adoc and process it by loading all the includes, but not
parsing or rendering it, just copying it to ${main.basedir}
(defaults to ${basedir}, i.e. the root of the project). If there are
any changes in the README it will then show up after a Maven build as
a modified file in the correct place. Just commit it and push the change.

=== Working with the code
If you don't have an IDE preference we would recommend that you use
https://www.springsource.com/developer/sts[Spring Tools Suite] or
https://eclipse.org[Eclipse] when working with the code. We use the
https://eclipse.org/m2e/[m2eclipse] eclipse plugin for maven support. Other IDEs and tools
should also work without issue as long as they use Maven 3.3.3 or better.

==== Importing into eclipse with m2eclipse
We recommend the https://eclipse.org/m2e/[m2eclipse] eclipse plugin when working with
eclipse. If you don't already have m2eclipse installed it is available from the "eclipse
marketplace".

NOTE: Older versions of m2e do not support Maven 3.3, so once the
projects are imported into Eclipse you will also need to tell
m2eclipse to use the right profile for the projects. If you
see many different errors related to the POMs in the projects, check
that you have an up to date installation. If you can't upgrade m2e,
add the "spring" profile to your settings.xml. Alternatively you can
copy the repository settings from the "spring" profile of the parent
pom into your settings.xml.

==== Importing into eclipse without m2eclipse
If you prefer not to use m2eclipse you can generate eclipse project metadata using the
following command:

[indent=0]

$ ./mvnw eclipse:eclipse

The generated eclipse projects can be imported by selecting import existing projects
from the file menu.

== Contributing

:spring-cloud-build-branch: master

Spring Cloud is released under the non-restrictive Apache 2.0 license,
and follows a very standard Github development process, using Github
tracker for issues and merging pull requests into master. If you want
to contribute even something trivial please do not hesitate, but
follow the guidelines below.

=== Sign the Contributor License Agreement
Before we accept a non-trivial patch or pull request we will need you to sign the
https://cla.pivotal.io/sign/spring[Contributor License Agreement].
Signing the contributor's agreement does not grant anyone commit rights to the main
repository, but it does mean that we can accept your contributions, and you will get an
author credit if we do. Active contributors might be asked to join the core team, and
given the ability to merge pull requests.

=== Code of Conduct
This project adheres to the Contributor Covenant https://github.com/spring-cloud/spring-cloud-build/blob/master/docs/src/main/asciidoc/code-of-conduct.adoc[code of
conduct]. By participating, you are expected to uphold this code. Please report
unacceptable behavior to spring-code-of-conduct@pivotal.io.

=== Code Conventions and Housekeeping
None of these is essential for a pull request, but they will all help. They can also be
added after the original pull request but before a merge.

• Use the Spring Framework code format conventions. If you use Eclipse
  you can import formatter settings using the
  eclipse-code-formatter.xml file from the
  https://raw.githubusercontent.com/spring-cloud/spring-cloud-build/master/spring-cloud-dependencies-parent/eclipse-code-formatter.xml[Spring
  Cloud Build] project. If using IntelliJ, you can use the
  https://plugins.jetbrains.com/plugin/6546[Eclipse Code Formatter
  Plugin] to import the same file.
• Make sure all new .java files to have a simple Javadoc class comment with at least an
  @author tag identifying you, and preferably at least a paragraph on what the class is
  for.
• Add the ASF license header comment to all new .java files (copy from existing files
  in the project)
• Add yourself as an @author to the .java files that you modify substantially (more
  than cosmetic changes).
• Add some Javadocs and, if you change the namespace, some XSD doc elements.
• A few unit tests would help a lot as well -- someone has to do it.
• If no-one else is using your branch, please rebase it against the current master (or
  other target branch in the main project).
• When writing a commit message please follow https://tbaggery.com/2008/04/19/a-note-about-git-commit-messages.html[these conventions],
  if you are fixing an existing issue please add Fixes gh-XXXX at the end of the commit
  message (where XXXX is the issue number).

=== Checkstyle

Spring Cloud Build comes with a set of checkstyle rules. You can find them in the spring-cloud-build-tools module. The most notable files under the module are:

.spring-cloud-build-tools/

└── src
   ├── checkstyle
   │   └── checkstyle-suppressions.xml <3>
   └── main
   └── resources
   ├── checkstyle-header.txt <2>
   └── checkstyle.xml <1>

<1> Default Checkstyle rules
<2> File header setup
<3> Default suppression rules

==== Checkstyle configuration

Checkstyle rules are disabled by default. To add checkstyle to your project just define the following properties and plugins.

.pom.xml

<reporting>
    <plugins>
        <plugin> <5>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-checkstyle-plugin</artifactId>
        </plugin>
    </plugins>
</reporting>

If you need to suppress some rules (e.g. line length needs to be longer), then it's enough for you to define a file under ${project.root}/src/checkstyle/checkstyle-suppressions.xml with your suppressions. Example:

.projectRoot/src/checkstyle/checkstyle-suppresions.xml

It's advisable to copy the ${spring-cloud-build.rootFolder}/.editorconfig and ${spring-cloud-build.rootFolder}/.springformat to your project. That way, some default formatting rules will be applied. You can do so by running this script:

$ curl https://raw.githubusercontent.com/spring-cloud/spring-cloud-build/master/.editorconfig -o .editorconfig
$ touch .springformat

=== IDE setup

==== Intellij IDEA

In order to setup Intellij you should import our coding conventions, inspection profiles and set up the checkstyle plugin.
The following files can be found in the https://github.com/spring-cloud/spring-cloud-build/tree/master/spring-cloud-build-tools[Spring Cloud Build] project.

.spring-cloud-build-tools/

└── src
   ├── checkstyle
   │   └── checkstyle-suppressions.xml <3>
   └── main
   └── resources
   ├── checkstyle-header.txt <2>
   ├── checkstyle.xml <1>
   └── intellij
      ├── Intellij_Project_Defaults.xml <4>
      └── Intellij_Spring_Boot_Java_Conventions.xml <5>

<1> Default Checkstyle rules
<2> File header setup
<3> Default suppression rules
<4> Project defaults for Intellij that apply most of Checkstyle rules
<5> Project style conventions for Intellij that apply most of Checkstyle rules

.Code style

image::https://raw.githubusercontent.com/spring-cloud/spring-cloud-build/{spring-cloud-build-branch}/docs/src/main/asciidoc/images/intellij-code-style.png[Code style]

Go to File -> Settings -> Editor -> Code style. There click on the icon next to the Scheme section. There, click on the Import Scheme value and pick the Intellij IDEA code style XML option. Import the spring-cloud-build-tools/src/main/resources/intellij/Intellij_Spring_Boot_Java_Conventions.xml file.

.Inspection profiles

image::https://raw.githubusercontent.com/spring-cloud/spring-cloud-build/{spring-cloud-build-branch}/docs/src/main/asciidoc/images/intellij-inspections.png[Code style]

Go to File -> Settings -> Editor -> Inspections. There click on the icon next to the Profile section. There, click on the Import Profile and import the spring-cloud-build-tools/src/main/resources/intellij/Intellij_Project_Defaults.xml file.

.Checkstyle

To have Intellij work with Checkstyle, you have to install the Checkstyle plugin. It's advisable to also install the Assertions2Assertj to automatically convert the JUnit assertions

image::https://raw.githubusercontent.com/spring-cloud/spring-cloud-build/{spring-cloud-build-branch}/docs/src/main/asciidoc/images/intellij-checkstyle.png[Checkstyle]

Go to File -> Settings -> Other settings -> Checkstyle. There click on the + icon in the Configuration file section. There, you'll have to define where the checkstyle rules should be picked from. In the image above, we've picked the rules from the cloned Spring Cloud Build repository. However, you can point to the Spring Cloud Build's GitHub repository (e.g. for the checkstyle.xml : https://raw.githubusercontent.com/spring-cloud/spring-cloud-build/master/spring-cloud-build-tools/src/main/resources/checkstyle.xml). We need to provide the following variables:

• checkstyle.header.file - please point it to the Spring Cloud Build's, spring-cloud-build-tools/src/main/resources/checkstyle-header.txt file either in your cloned repo or via the https://raw.githubusercontent.com/spring-cloud/spring-cloud-build/master/spring-cloud-build-tools/src/main/resources/checkstyle-header.txt URL.
• checkstyle.suppressions.file - default suppressions. Please point it to the Spring Cloud Build's, spring-cloud-build-tools/src/checkstyle/checkstyle-suppressions.xml file either in your cloned repo or via the https://raw.githubusercontent.com/spring-cloud/spring-cloud-build/master/spring-cloud-build-tools/src/checkstyle/checkstyle-suppressions.xml URL.
• checkstyle.additional.suppressions.file - this variable corresponds to suppressions in your local project. E.g. you're working on spring-cloud-contract. Then point to the project-root/src/checkstyle/checkstyle-suppressions.xml folder. Example for spring-cloud-contract would be: /home/username/spring-cloud-contract/src/checkstyle/checkstyle-suppressions.xml.

IMPORTANT: Remember to set the Scan Scope to All sources since we apply checkstyle rules for production and test sources.