Writing REST Services in Java: Part 7 Moving To Production

Previous Post : Part Six: Security & Authorization
Get the Code: https://github.com/iainporter/rest-java

This post will discuss the steps needed to configure the project to deploy it in a staging or production environment.
It is only of interest if you wish to use the code and deploy it beyond the in-memory defaults.

Database Configuration

The project makes use of Spring's active profiles.

Profiles can be set with a System property or, when running gradle by setting the property in gradle.properties
Choices are dev | local | staging | production

When running the dev profile the database is an in-memory H2 database.

The first step is to test that the application will run against a real database. The local profile can be used for this purpose.

The configuration file is at 

src/main/resources/META-INF/spring/data-context.xml

You can change the properties to suit your local environment.

Test the application by setting the active profile to local and executing:

gradle clean build integrationTest

If the build is successful there should now be test data in the database.

Adding indexes and Message Store tables

On start up if the tables do not exist they will be created. The next step is to add the relevant indexes by executing the script in:

src/main/resources/schema/indexes.sql

Finally we need to add the tables used by Spring Integration to persist messages on the queues. There are scripts for various database types that ship with the Spring source code in the spring-integration-jdbc.jar
A default script for MySql is available in

src/main/resources/schema/message_store.sql

There are placeholders in data-context.xml for adding the staging and production profile database configurations. Repeat the above steps for each of these environments.

Email Configuration

Both the dev and local profiles use a MockJavaMailSender which does not deliver any messages but stores them in a HashMap. When you are ready to send real mail messages then you will have to configure the mail properties in

src/main/resources/META-INF/spring/email-template-context.xml

As discussed in Part Three you can choose from a variety of different mail services. The simplest is to use a gmail or yahoo account. There are also many useful bulk mail services that you would want to use in production such as CritSend, MailJet, MailChimp, etc.

One final configuration point to mention is that the mail service is backed by several message queues implemented in Spring Integration. These queues have a backing message store to which to temporarily persist messages until they are delivered. When running with the dev or local profiles the message store is a simple in-memory store which will not survive a crash or restart. For staging and production the messages are persisted to the datastore configured for that profile, hence the requirement for the sql script mentioned above to create those tables.

Additional Configuration

There are a few other properties that you can set in

src/main/resources/properties/app.properties

Here you can change how long session tokens should remain active, which authorization method to use, set email preferences, etc. See the comments in that file for full details

The next post will discuss how to write new services and the final post will discuss deploying to the cloud.