# spring-cloud-config

**Repository Path**: wang_shenbing/spring-cloud-config

## Basic Information

- **Project Name**: spring-cloud-config
- **Description**: No description available
- **Primary Language**: Java
- **License**: Not specified
- **Default Branch**: 1.0.0.M2
- **Homepage**: None
- **GVP Project**: No

## Statistics

- **Stars**: 0
- **Forks**: 0
- **Created**: 2021-11-19
- **Last Updated**: 2021-11-19

## Categories & Tags

**Categories**: Uncategorized

**Tags**: None

## README

// Do not edit this file (e.g. go instead to src/main/asciidoc)

Spring Cloud Config provides server and client-side support for externalized configuration in a distributed system. With the Config Server you have a central place to manage external properties for applications across all environments. The concepts on both client and server map identically to the Spring `Environment` and `PropertySource` abstractions, so they fit very well with Spring applications, but can be used with any application running in any language. As an application moves through the deployment pipeline from dev to test and into production you can manage the configuration between those environments and be certain that applications have everything they need to run when they migrate. The default implementation of the server storage backend uses git so it easily supports labelled versions of configuration environments, as well as being accessible to a wide range of tooling for managing the content.  It is easy to add alternative implementations and plug them in with Spring configuration.


== Features

=== Spring Cloud Config Server

* HTTP, resource-based API for external configuration (name-value pairs, or equivalent YAML content)
* Encrypt and decrypt property values (symmetric or asymmetric)
* Embeddable easily in a Spring Boot application using `@EnableConfigServer`

=== Spring Cloud Config Client

Specifically for Spring applications:

* Bind to the Config Server and initialize Spring `Environment` with remote property sources
* Encrypt and decrypt property values (symmetric or asymmetric)
* `@RefreshScope` for Spring `@Beans` that want to be re-initialized when configuration changes
* Management endpoints:
** `/env` for updating `Environment` and rebinding `@ConfigurationProperties` and log levels
** `/refresh` for refreshing the `@RefreshScope` beans
** `/restart` for restarting the Spring context (disabled by default)
** `/pause` and `/resume` for calling the `Lifecycle` methods (`stop()` and `start()` on the `ApplicationContext`)
* Bootstrap appplication context: a parent context for the main application that can be trained to do anything (by default it binds to the Config Server, and decrypts property values)

== Quick Start

Start the server:

----
$ cd spring-cloud-config-server
$ mvn spring-boot:run
----

The server is a Spring Boot application so you can build the jar file
and run that (`java -jar ...`) or pull it down from a Maven
repository. Then try it out as a client:

----
$ curl localhost:8888/foo/development
{"name":"development","label":"master","propertySources":[
  {"name":"https://github.com/scratches/config-repo/foo-development.properties","source":{"bar":"spam"}},
  {"name":"https://github.com/scratches/config-repo/foo.properties","source":{"foo":"bar"}}
]}
----

The default strategy for locating property sources is to clone a git
repository (at "spring.cloud.config.server.uri") and use it to
initialize a mini `SpringApplication`. The mini-application's
`Environment` is used to enumerate property sources and publish them
via a JSON endpoint. The service has resources in the form:

----
/{application}/{profile}[/{label}]
/{application}-{profile}.yml
/{label}/{application}-{profile}.yml
/{application}-{profile}.properties
/{label}/{application}-{profile}.properties
----

where the "application" is injected as the "spring.config.name" in the
`SpringApplication` (i.e. what is normally "application" in a regular
Spring Boot app), "profile" is an active profile (or comma-separated
list of properties), and "label" is an optional git label (defaults to
"master".) The YAML and properties forms are coalesced into a single
map, even if the origin of the values (reflected in the
"propertySources" of the "standard" form) has multiple sources.

=== Client Side Usage

To use these features in an application, just build it as a Spring
Boot application that depends on spring-cloud-config-client (e.g. see
the test cases for the config-client, or the sample app). The most
convenient way to add the dependency is via a Spring Boot starter
`org.springframework.cloud:spring-cloud-starter`. There is also a
parent pom and BOM (`spring-cloud-starters`) for Maven users and a
Spring IO version management properties file for Gradle and Spring CLI
users. Example Maven configuration:

[source,xml,indent=0]
.pom.xml
----
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.1.7.RELEASE</version>
        <relativePath /> <!-- lookup parent from repository -->
    </parent>

	<dependencyManagement>
		<dependencies>
			<dependency>
				<groupId>org.springframework.cloud</groupId>
				<artifactId>spring-cloud-starters</artifactId>
				<version>1.0.0.BUILD-SNAPSHOT</version>
				<type>pom</type>
				<scope>import</scope>
			</dependency>
		</dependencies>
	</dependencyManagement>

	<dependencies>
		<dependency>
			<groupId>org.springframework.cloud</groupId>
			<artifactId>spring-cloud-starter</artifactId>
		</dependency>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-test</artifactId>
			<scope>test</scope>
		</dependency>
	</dependencies>

	<build>
		<plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
		</plugins>
	</build>

    <!-- repositories also needed for snapshots and milestones -->
----

Then you can create a standard Spring Boot application, like this simple HTTP server:

----
@Configuration
@EnableAutoConfiguration
@RestController
public class Application {

    @RequestMapping("/")
    public String home() {
        return "Hello World!";
    }

    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }

}
----

When it runs it will pick up the external configuration from the
default local config server on port 8888 if it is running. To modify
the startup behaviour you can change the location of the config server
using `bootstrap.properties` (like `application.properties` but for
the bootstrap phase of an application context), e.g.

----
spring.cloud.config.uri: http://myconfigserver.com
----

The bootstrap properties will show up in the `/env` endpoint as a
high-priority property source, e.g.

----
$ curl localhost:8080/env
{
  "profiles":[],
  "configService:https://github.com/scratches/config-repo/bar.properties":{"foo":"bar"},
  "servletContextInitParams":{},
  "systemProperties":{...},
  ...
}
----

(a property source called "configService:<URL of remote
repository>/<file name>" contains the property "foo" with value
"bar" and is highest priority).

=== Sample Application

There is a sample application
https://github.com/spring-cloud/spring-cloud-config/tree/master/spring-cloud-config-sample[here]. It
is a Spring Boot application so you can run it using the usual
mechanisms (for instance "mvn spring-boot:run"). When it runs it will
look for the config server on "http://localhost:8888" by default, so
you could run the server as well to see it all working together.

The sample has a test case where the config server is also started in
the same JVM (with a different port), and the test asserts that an
environment property from the git configuration repo is present. To
change the location of the config server just set
"spring.cloud.config.uri" in "bootstrap.yml" (or via System
properties etc.).

The test case has a `main()` method that runs the server in the same
way (watch the logs for its port), so you can run the whole system in
one process and play with it (e.g. right click on the main in your IDE
and run it). The `main()` method uses `target/config` for the working
directory of the git repository, so you can make local changes there
and see them reflected in the running app.

----
$ curl localhost:8080/env/foo
bar
$ vi target/config/bar.properties
.. change value of "foo", optionally commit
$ curl localhost:8080/refresh
["foo"]
$ curl localhost:8080/env/foo
baz
----

The refresh endpoint reports that the "foo" property changed.

== Building

== Basic Compile and Test

To build the source you will need to install
http://maven.apache.org/run-maven/index.html[Apache Maven] v3.0.6 or above and JDK 1.7.

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

----
$ mvn install -s .settings.xml
----

NOTE: You may need to increase the amount of memory available to Maven by setting
a `MAVEN_OPTS` environment variable with the value `-Xmx512m -XX:MaxPermSize=128m`

The `.settings.xml` is only required the first time (or after updates
to dependencies). It is there to provide repository declarations so
that those do not need to be hard coded in the project poms.

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 will be able git
credentials and you already have those.

If you need mongo, rabbit or redis, see the README in the [scripts
demo repository](https://github.com/spring-cloud-samples/scripts) for
instructions. For example consider using the "fig.yml" with
[Fig](http://www.fig.sh/) to run them in Docker containers.

== 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.

== Pull Requests

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://support.springsource.com/spring_committer_signup[contributor's
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 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 and you follow
  the ``Importing into eclipse'' instructions below you should get project specific
  formatting automatically. You can also import formatter settings using the
  `eclipse-code-formatter.xml` file from the `eclipse` folder. If using IntelliJ, you can
  use the http://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).

=== Working with the code
If you don't have an IDE preference we would recommend that you use
http://www.springsource.com/developer/sts[Spring Tools Suite] or
http://eclipse.org[Eclipse] when working with the code. We use the
http://eclipse.org/m2e/[m2eclipe] eclipse plugin for maven support. Other IDEs and tools
should also work without issue.

=== Importing into eclipse with m2eclipse
We recommend the http://eclipse.org/m2e/[m2eclipe] eclipse plugin when working with
eclipse. If you don't already have m2eclipse installed it is available from the "eclipse
marketplace".

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

[indent=0]
----
	$ mvn eclipse:eclipse
----

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

=== Importing into other IDEs
Maven is well supported by most Java IDEs. Refer to you vendor documentation.