[[deployment]]
== Deploying Spring Boot applications

[partintro]
--
Spring Boot's flexible packaging options provide a great deal of choice when it comes to
deploying your application. You can easily deploy Spring Boot applications to a variety
of cloud platforms, to a container images (such as Docker) or to virtual/real machines.

This section covers some of the more common deployment scenarios.
--



[[cloud-deployment]]
== Deploying to the cloud

Spring Boot's executable jars are ready-made for most popular cloud PaaS
(platform-as-a-service) providers. These providers tend to require that you
"`bring your own container`"; they manage application processes (not Java applications
specifically), so they need some intermediary layer that adapts _your_ application to the
_cloud's_ notion of a running process.

Two popular cloud providers, Heroku and Cloud Foundry, employ a "`buildpack`" approach.
The buildpack wraps your deployed code in whatever is needed to _start_ your
application: it might be a JDK and a call to `java`, it might be an embedded webserver,
or it might be a full-fledged application server. A buildpack is pluggable, but ideally
you should be able to get by with as few customizations to it as possible.
This reduces the footprint of functionality that is not under your control. It minimizes
divergence between development and production environments.

Ideally, your application, like a Spring Boot executable jar, has everything that it needs
to run packaged within it.

In this section we'll look at what it takes to get the
<<getting-started.adoc#getting-started-first-application, simple application that we
developed>> in the "`Getting Started`" section up and running in the Cloud.



[[cloud-deployment-cloud-foundry]]
=== Cloud Foundry
Cloud Foundry provides default buildpacks that come into play if no other buildpack is
specified. The Cloud Foundry https://github.com/cloudfoundry/java-buildpack[Java buildpack]
has excellent support for Spring applications, including Spring Boot.  You can deploy
stand-alone executable jar applications, as well as traditional `.war` packaged
applications.

Once you've built your application (using, for example, `mvn clean package`) and
http://docs.cloudfoundry.org/devguide/installcf/install-go-cli.html[installed the `cf`
command line tool], simply deploy your application using the `cf push` command as follows,
substituting the path to your compiled `.jar`. Be sure to have
http://docs.cloudfoundry.org/devguide/installcf/whats-new-v6.html#login[logged in with your
`cf` command line client] before pushing an application.

[indent=0,subs="verbatim,quotes,attributes"]
----
	$ cf push acloudyspringtime -p target/demo-0.0.1-SNAPSHOT.jar
----

See the http://docs.cloudfoundry.org/devguide/installcf/whats-new-v6.html#push[`cf push`
documentation] for more options. If there is a Cloud Foundry
http://docs.cloudfoundry.org/devguide/deploy-apps/manifest.html[`manifest.yml`]
file present in the same directory, it will be consulted.

NOTE: Here we are substituting `acloudyspringtime` for whatever value you give `cf`
as the name of your application.

At this point `cf` will start uploading your application:

[indent=0,subs="verbatim,quotes,attributes"]
----
	Uploading acloudyspringtime... *OK*
	Preparing to start acloudyspringtime... *OK*
	-----> Downloaded app package (*8.9M*)
	-----> Java Buildpack source: system
	-----> Downloading Open JDK 1.7.0_51 from .../x86_64/openjdk-1.7.0_51.tar.gz (*1.8s*)
	       Expanding Open JDK to .java-buildpack/open_jdk (*1.2s*)
	-----> Downloading Spring Auto Reconfiguration from  0.8.7 .../auto-reconfiguration-0.8.7.jar (*0.1s*)
	-----> Uploading droplet (*44M*)
	Checking status of app 'acloudyspringtime'...
	  0 of 1 instances running (1 starting)
	  ...
	  0 of 1 instances running (1 down)
	  ...
	  0 of 1 instances running (1 starting)
	  ...
	  1 of 1 instances running (1 running)

	App started
----

Congratulations! The application is now live!

It's easy to then verify the status of the deployed application:

[indent=0,subs="verbatim,quotes,attributes"]
----
	$ cf apps
	Getting applications in ...
	OK

	name                 requested state   instances   memory   disk   urls
	...
	acloudyspringtime    started           1/1         512M     1G     acloudyspringtime.cfapps.io
	...
----

Once Cloud Foundry acknowledges that your application has been deployed, you should be
able to hit the application at the URI given, in this case
`http://acloudyspringtime.cfapps.io/`.



[[cloud-deployment-cloud-foundry-services]]
==== Binding to services
By default, metadata about the running application as well as service connection
information is exposed to the application as environment variables (for example:
`$VCAP_SERVICES`). This architecture decision is due to Cloud Foundry's polyglot
(any language and platform can be supported as a buildpack) nature; process-scoped
environment variables are language agnostic.

Environment variables don't always make for the easiest API so Spring Boot automatically
extracts them and flattens the data into properties that can be accessed through
Spring's `Environment` abstraction:

[source,java,indent=0]
----
	@Component
	class MyBean implements EnvironmentAware {

		private String instanceId;

		@Override
		public void setEnvironment(Environment environment) {
			this.instanceId = environment.getProperty("vcap.application.instance_id");
		}

		// ...

	}
----

All Cloud Foundry properties are prefixed with `vcap`. You can use vcap properties to
access application information (such as the public URL of the application) and service
information (such as database credentials). See `VcapApplicationListener` Javadoc for
complete details.

TIP: The http://cloud.spring.io/spring-cloud-connectors/[Spring Cloud Connectors] project
is a better fit for tasks such as configuring a DataSource. Spring Boot includes
auto-configuration support and a `spring-boot-starter-cloud-connectors` starter POM.



[[cloud-deployment-heroku]]
=== Heroku
Heroku is another popular PaaS platform. To customize Heroku builds, you provide a
`Procfile`, which provides the incantation required to deploy an application. Heroku
assigns a `port` for the Java application to use and then ensures that routing to the
external URI works.

You must configure your application to listen on the correct port. Here's the `Procfile`
for our starter REST application:

[indent=0]
----
	web: java -Dserver.port=$PORT -jar target/demo-0.0.1-SNAPSHOT.jar
----

Spring Boot makes `-D` arguments available as properties accessible from a Spring
`Environment` instance. The `server.port` configuration property is fed to the embedded
Tomcat, Jetty or Undertow instance which then uses it when it starts up. The `$PORT`
environment variable is assigned to us by the Heroku PaaS.

Heroku by default will use Java 1.8. This is fine as long as your Maven or Gradle build
is set to use the same version (Maven users can use the java.version property). If you
want to use JDK 1.7, create a new file adjacent to your `pom.xml` and `Procfile`,
called `system.properties`. In this file add the following:

[indent=0]
----
	java.runtime.version=1.7
----

This should be everything you need. The most common workflow for Heroku deployments is to
`git push` the code to production.

[indent=0,subs="verbatim,quotes,attributes"]
----
	$ git push heroku master

	Initializing repository, *done*.
	Counting objects: 95, *done*.
	Delta compression using up to 8 threads.
	Compressing objects: 100% (78/78), *done*.
	Writing objects: 100% (95/95), 8.66 MiB | 606.00 KiB/s, *done*.
	Total 95 (delta 31), reused 0 (delta 0)

	-----> Java app detected
	-----> Installing OpenJDK 1.8... *done*
	-----> Installing Maven 3.3.1... *done*
	-----> Installing settings.xml... *done*
	-----> Executing: mvn -B -DskipTests=true clean install

	       [INFO] Scanning for projects...
	       Downloading: http://repo.spring.io/...
	       Downloaded: http://repo.spring.io/... (818 B at 1.8 KB/sec)
			....
	       Downloaded: http://s3pository.heroku.com/jvm/... (152 KB at 595.3 KB/sec)
	       [INFO] Installing /tmp/build_0c35a5d2-a067-4abc-a232-14b1fb7a8229/target/...
	       [INFO] Installing /tmp/build_0c35a5d2-a067-4abc-a232-14b1fb7a8229/pom.xml ...
	       [INFO] ------------------------------------------------------------------------
	       [INFO] *BUILD SUCCESS*
	       [INFO] ------------------------------------------------------------------------
	       [INFO] Total time: 59.358s
	       [INFO] Finished at: Fri Mar 07 07:28:25 UTC 2014
	       [INFO] Final Memory: 20M/493M
	       [INFO] ------------------------------------------------------------------------

	-----> Discovering process types
	       Procfile declares types -> *web*

	-----> Compressing... *done*, 70.4MB
	-----> Launching... *done*, v6
	       http://agile-sierra-1405.herokuapp.com/ *deployed to Heroku*

	To git@heroku.com:agile-sierra-1405.git
	 * [new branch]      master -> master
----

Your application should now be up and running on Heroku.



[[cloud-deployment-openshift]]
=== Openshift
https://www.openshift.com/[Openshift] is the RedHat public (and enterprise) PaaS solution.
Like Heroku, it works by running scripts triggered by git commits, so you can script
the launching of a Spring Boot application in pretty much any way you like as long as the
Java runtime is available (which is a standard feature you can ask for at Openshift).
To do this you can use the
https://www.openshift.com/developers/do-it-yourself[DIY Cartridge] and hooks in your
repository under `.openshift/action_scripts`:

The basic model is to:

1. Ensure Java and your build tool are installed remotely, e.g. using a `pre_build` hook
   (Java and Maven are installed by default, Gradle is not)
2. Use a `build` hook to build your jar (using Maven or Gradle), e.g.
+
[indent=0]
----
	#!/bin/bash
	cd $OPENSHIFT_REPO_DIR
	mvn package -s .openshift/settings.xml -DskipTests=true
----
+
3. Add a `start` hook that calls `java -jar ...`
+
[indent=0]
----
	#!/bin/bash
	cd $OPENSHIFT_REPO_DIR
	nohup java -jar target/*.jar --server.port=${OPENSHIFT_DIY_PORT} --server.address=${OPENSHIFT_DIY_IP} &
----
+
4. Use a `stop` hook (since the start is supposed to return cleanly), e.g.
+
[indent=0]
----
	#!/bin/bash
	source $OPENSHIFT_CARTRIDGE_SDK_BASH
	PID=$(ps -ef | grep java.*\.jar | grep -v grep | awk '{ print $2 }')
	if [ -z "$PID" ]
	then
	    client_result "Application is already stopped"
	else
	    kill $PID
	fi
----
+
5. Embed service bindings from environment variables provided by the platform
in your `application.properties`, e.g.
+
[indent=0]
----
	spring.datasource.url: jdbc:mysql://${OPENSHIFT_MYSQL_DB_HOST}:${OPENSHIFT_MYSQL_DB_PORT}/${OPENSHIFT_APP_NAME}
	spring.datasource.username: ${OPENSHIFT_MYSQL_DB_USERNAME}
	spring.datasource.password: ${OPENSHIFT_MYSQL_DB_PASSWORD}
----

There's a blog on https://www.openshift.com/blogs/run-gradle-builds-on-openshift[running
Gradle in Openshift] on their website that will get you started with a gradle build to
run the app.



[[cloud-deployment-gae]]
=== Google App Engine
Google App Engine is tied to the Servlet 2.5 API, so you can't deploy a Spring Application
there without some modifications. See the <<howto.adoc#howto-servlet-2-5, Servlet 2.5 section>>
of this guide.


[[deployment-service]]
== Installing Spring Boot applications
In additional to running Spring Boot applications using `java -jar` it is also possible
to execute applications directly on Unix systems (Linux, OSX, FreeBSD etc). This makes it
very easy to install and manage Spring Boot applications in common production
environments. As long as you are generating '`fully executable`' jars from your build, and
you are not using a custom `embeddedLaunchScript`, the following techniques can be used.



=== Unix/Linux services
Spring Boot application can be easily started as Unix/Linux services using either `init.d`
or `systemd`.



==== Installation as a init.d (System V) service
The default executable script that is embedded into Spring Boot executable jars will act
as an `init.d` script when it is symlinked to `/etc/init.d`. The standard `start`, `stop`,
`restart` and `status` commands can be used. The script supports the following features:

* Starts the services as the user that owns the jar file
* Tracks application PIDs using `/var/run/<appname>/<appname>.pid`
* Writes console logs to `/var/log/<appname>.log`

Assuming that you have a Spring Boot application installed in `/var/myapp`, to install a
Spring Boot application as an `init.d` service simply create a symlink:

[indent=0,subs="verbatim,quotes,attributes"]
----
	$ sudo link -s /var/myapp/myapp.jar /etc/init.d/myapp
----

TIP: It is advisable to create a specific user account to run you application. Ensure
that you have set the owner of the jar file using `chown` before installing your service.

Once installed, you can start and stop the service in the usual way. You can also flag the
application to start automatically using your standard operating system tools. For example,
if you use Debian:

[indent=0,subs="verbatim,quotes,attributes"]
----
	$ update-rc.d myapp defaults <priority>
----

=== Running a JAR as a regular (not service) script

The script accepts the following parameters as environment variables, so you can change the
default behaviour in a script or on the command line:

* `MODE` - the "mode" of operation. The default depends on the way the jar was built, but
will usually be "auto" (meaning it tries to guess if it is an init script by checking if
it is a symlink in a directory called "init.d"). You can explicitly set it to "service"
so that the "stop|start|status|restart" commands work, or to "run" if you just want to
run the script and not in the background.

* `PID_FOLDER` - the root name of the pid folder (`/var/run` by default).

* `LOG_FOLDER` - the name of the folder to put log files in (`/var/log` by default).

* `APP_NAME` - the name of the app. If the jar is run from a symlink the script guesses the 
app name, but if it is not a symlink, or you want to explicitly set the app name this can be
useful.

* `JAVA_HOME` - the location of the `java` executable is discovered by using the `PATH` by 
default, but you can set it explicitly if there is an executable file at `$JAVA_HOME/bin/java`.

* `JARFILE` - the explicit location of the jar file, in case the script is being used to launch
a jar that it is not actually embedded in.

* `DEBUG` - if not empty will set the `-x` flag on the shell process, making it easy to
see the logic in the script.


==== Installation as a systemd service
Systemd is the successor to `init.d` scripts, and now being used by many many modern Linux
distributions. Although you can continue to use `init.d` script with `systemd`, it is also
possible to launch Spring Boot applications using `systemd` '`service`' scripts.

For example, to run a Spring Boot application installed in `var/myapp` you can add the
following script in `/etc/systemd/system/myapp.service`:

[indent=0]
----
	[Unit]
	Description=myapp
	After=syslog.target

	[Service]
	ExecStart=/var/myapp/myapp.jar

	[Install]
	WantedBy=multi-user.target
----

TIP: Remember to change the `Description` and `ExecStart` fields for your application.



[[deployment-whats-next]]
== What to read next
Check out the http://www.cloudfoundry.com/[Cloud Foundry], https://www.heroku.com/[Heroku]
and https://www.openshift.com[Openshift] web sites for more information about the kinds of
features that a PaaS can offer. These are just three of the most popular Java PaaS
providers, since Spring Boot is so amenable to cloud-based deployment you're free to
consider other providers as well.

The next section goes on to cover the _<<spring-boot-cli.adoc#cli, Spring Boot CLI>>_;
or you can jump ahead to read about
_<<build-tool-plugins.adoc#build-tool-plugins, build tool plugins>>_.

