Build Java Applications with Cache layer and deploy with CI/CD

Abhishek Gupta

Published in

Oracle Developers

4 min readJun 6, 2017

In this blog we will look at:

How to interact with the Application Container Cloud Cache using its (open source) Java SDK
Build an application on top of it
Setup Continuous Integration & Continuous Deployment (CI/CD) using Developer Cloud Service

Application

The application is a simple one which fetches the price of a stock from the cache. It demonstrates other features (in addition to basic caching) such as

Cache loader — if the key (stock name) does not exist in the cache (since it was never searched for or has expired), the cache loader logic kicks in and fetches the price using a REST call to an endpoint
Serializer — Allows us to work with our domain object (Ticker) and takes care of the transformation logic
Expiry — A cache-level expiry is enforced after which the entry is purged from the cache
Metrics — get common metrics such as cache size, hits, misses etc.

Code

Let’s look at some code snippets for our application and each of the features mentioned above

Project is available on Github

Cache operations

This example exposes the get cache operation over a REST endpoint implemented using Jersey (JAX-RS API)

Cache Loader

PriceLoader.java contains the logic to fetch the price from an external source

Serializer

TickerSerializer.java Converts to and from Ticker.java and its String representation

Expiry

Purges the cache entry when this threshold is hit and causes the cache loader invocation is the expired entry is looked up (get) again

Metrics

Many cache metrics can be extracted — common ones are exposed over a REST endpoint

Some of the metrics are global and other are not. Please refer to the CacheMetrics javadoc for details

Setup of Oracle Cloud services

Application Container Cloud

The only setup required is to create the Cache. It’s very simple and can be done quickly using the documentation.

Please make sure that the name of the cache is the same as one used in the code and configuration (Developer Cloud) i.e test-cache. If not, please update the references

Developer Cloud

You would need to configure Developer Cloud for the build as well as Continuous Deployment process. You can refer to previous blogs for the same — some of the details specific to this example will be highlighted here

References

Provide App Container Cloud (configuration) descriptors

The manifest,json provided here will override the one in your zip file (if any) — its not compulsory to provide it here
Providing the deployment.json details is compulsory (in this CI/CD scenario ) since it cannot be included in the zip file

Deployment confirmation in Oracle Developer Cloud

Status in Oracle Application Container Cloud

Application URL has been highlighted

Test the application

Check price

Invoke the REST endpoint (check the application URL) e.g.

curl -X https://acc-cache-dcs-domain007.apaas.us6.oraclecloud.com/price/ORCL

If you try fetching the price of the stock after the expiry (default is 5 seconds), you should see a change in the time attribute (and the price as well — if it has actually changed)

Check cache metrics

Invoke a HTTP GET (use curl or browser) to the REST endpoint (check the application URL) e.g.

curl -X https://acc-cache-dcs-domain007.apaas.us6.oraclecloud.com/metrics

Test the CI/CD flow

Make some code changes and push them to the Developer Cloud service Git repo. This should

Automatically trigger the build, which once successful will
Automatically trigger the deployment process, and
Redeploy the new application version to Application Container Cloud

Don’t forget to…

check out the tutorials for Oracle Application Container Cloud — there is something for every runtime !
other blogs on Application Container Cloud
Github project for ACCS Java Cache SDK
Oracle Developer Cloud documentation

The views expressed in this post are my own and do not necessarily reflect the views of Oracle.