Sonatype Nexus 2.x: Using the REST API to clean-up your repository

Sonatype provides Nexus. An extensive artifact Repository Manager. It can hold large amounts of stored artifacts and still requests get processed quickly. Also it has an extensive easy to use API which is a definite asset. When a project has been running for a longer period (say years), the repository often gets filled with large numbers of artifacts. This can become especially troublesome if artifacts are quite large in size such as for example JSF EAR files. These artifacts might not even have been released (be part of a deployed release). Nexus provides the option to remove artifacts older than a specific date. This however might also remove artifacts which are dependencies of other artifacts (older releases) which you might want to keep. When those other artifacts are build, the build might break because the artifacts it refers to, have been removed. In order to allow more fine grained control over what to remove, I've created the following script. The script uses only the releases repository (snapshots are not taken into account. not sure what the script does there) Disclaimer: first test if this script does what you want in your situation. It is provided as is without any warranties.

Sonatype Nexus 3.0. Using the new Groovy API

Sonatype Nexus 3.0 does not have the REST API which was available in Nexus 2.x (see the discussion here). This provides a challenge in case you want to automate certain tasks. Nexus 3 does provide a Groovy API however which allows you to write your own scripts and upload them to Nexus. You can then call your scripts and use the JSON result. In order to get this working however, several things need to be done. First the script needs to be developed (during which code completion comes in handy). Next the script needs to be condensed to a single line and put in a JSON request. After that, the JSON request needs to be send to a specific endpoint. You can imagine this can be cumbersome. Sonatype has provided Groovy scripts to deploy their Groovy scripts. See here. I've created something similar using Python so you do not require a download of dependencies, a JVM and a Groovy installation to perform this task. This makes it more easy to do this from for example a build-server.

Oracle NoSQL Database 4.x and the Node.js driver 3.x

There are two ways you can access Oracle NoSQL database from a Node.js application. These are illustrated below. You can use the nosqldb-oraclejs driver and you can use Oracle REST Data Services.

In my previous blog post I illustrated how you can access Oracle NoSQL database by using the nosqldb-oraclejs driver. I encountered an issue when using the NoSQL database version 12R1.4.0.9 with the currently newest available Node.js driver for NoSQL database nosqldb-oraclejs 3.3.15.

Node.js and Oracle NoSQL Database

Oracle NoSQL Database is an interesting option to consider when you want a schemaless, fast, scale-able database which can provide relaxed (eventual) consistency. Oracle provides a Node.js driver for this database. In this blog I'll describe how to install Oracle NoSQL database and how to connect to it from a Node.js application.

The Node.js driver provided by Oracle is currently in preview version 3.3.7. It uses NoSQL client version 12.1.3.3.4 which does not work with 4.x versions of NoSQL database, so I downloaded Oracle NoSQL Database, Enterprise Edition 12cR1 (12.1.3.3.5) from here (the version number was closest to the version number of the client software).

Application Container Cloud: Node.js hosting with enterprise-grade features

Oracle's Application Container Cloud allows you to run Java SE, Node.js and PHP applications (and more is coming) in a Docker container hosted in the Oracle Public Cloud (OPC). Node.js can crash when applications do strange things. You can think of incorrect error handling, blocking calls or strange memory usage. In order to host Node.js in a manageable, stable and robust way in an enterprise application landscape, certain measures need to be taken. Application Container Cloud provides many of those measures and makes hosting Node.js applications easy. In this blog article I'll describe why you would want to use Oracle Application Container Cloud. I'll illustrate this with examples of my experience with the product.

Node.js: My first SOAP service

I created a simple HelloWorld SOAP service running on Node.js. Why did I do that? I wanted to try if Node.js was a viable solution to use as middleware layer in an application landscape. Not all clients can call JSON services. SOAP is still very common. If Node.js is to be considered for such a role, it should be possible to host SOAP services on it. My preliminary conclusion is that it is possible to host SOAP services on Node.js but you should carefully consider how you want to do this.

I tried to create the SOAP service in two distinct ways.

• xml2js. This Node.js module allows transforming XML to JSON and back. The JSON which is created can be used to easily access content with JavaScript. This module is fast and lightweight, but does not provide specific SOAP functionality.
• soap. This Node.js module provides some abstractions and features which make working with SOAP easier. The module is specifically useful when calling SOAP services (when Node.js is the client). When hosting SOAP services, the means to control the specific response to a call are limited (or undocumented)

Using both modules, I encountered some challenges which I will describe and how (and if) I solved them. You can find my sample code here.

Node.js: A simple pattern to increase perceived performance

The asynchronous nature of code running on Node.js provides many interesting options for service orchestration. In this example I will call two translation services (Google and SYSTRAN). I will call both of them quickly after each other (milliseconds). The first answer to be returned, will be the answer returned to the caller. The second answer will be ignored. I've used a minimal set of Node modules for this; http, url, request. Also I wrapped the translation API's to provide a similar interface which allows me to call them with the same request objects. You can download the code here. In the below picture this simple scenario is illustrated. I'm not going to talk about the event loop and the call stack. Watch this presentation for a nice elaboration on those.