Developers' Best Practices¶

It is time for D-Net development teams to find a strategy to improve our developement work!

The introduction of Jenkins and Nexus helped a lot in terms of code management, but now it is time to establish a set of guidelines to better co-ordinate our teams.
The following best practices are inspired by CNR developers' common sense, so we do not assume they are written in stones and applies as they are also in your cases.

So, you are strongly invited to comment/update this wiki page, so that we can reach a consensus.

Coding¶

Most of the D-Net modules have been migrated to from the old build system ant to maven. This implies some changes to the module directories and files, here's the migration guide:
http://ci.research-infrastructures.eu/public/docbook/MavenMigration.html

Maven compliant D-Net module structure:

.
├── pom.xml
├── src
│   ├── main
│   │   ├── java
│   │   │   └── eu
│   │   │       └── dnetlib
│   │   └── resources
│   │       └── eu
│   │           └── dnetlib
│   └── test
│       ├── java
│       │   └── eu
│       │       └── dnetlib
│       └── resources
│           └── eu
│               └── dnetlib
└── target
    └── classes

Hint: consider to define the svn:ignore property, set on the module root

cd <MODULE_NAME>
svn pe svn:ignore .

.classpath
.project
.settings
target 

Branching¶

It is always recommended to create a new branch when performing heavy changes to a module, rather than directly into trunk.

Use CI: trust Jenkins!¶

The developer should clean the .m2/repository/eu local repository from time to time to be sure that there are no modules installed locally.

Modules should be downloaded from Nexus in order to properly resolve dependencies.

Maven dependencies¶

For information about version conflict resolution with Maven3:

• http://docs.codehaus.org/display/MAVEN/Versioning
• https://cwiki.apache.org/confluence/display/MAVEN/Maven+3.x+Compatibility+Notes

Generally speaking, we suggest to use the keyword LATEST to refer to the last available artifact (snapshot or release) for a module.
Keep in mind that Maven3 considers:
1.0-alpha-1 < 1.0-beta-1 < 1.0-SNAPSHOT < 1.0 < 1.1-SNAPSHOT

How to change the version number of a snapshot?¶

Depending on the kind of changes you can decide to increase the artifact version according to the following guidelines:

• BIG CHANGES impact the MAJOR version number. Ex. 0.0.1 --> 1.0.0
  • Examples of big changes are: updates to service interfaces, shared libraries, new functionalities.
• MINOR CHANGES impact the MINOR version number. Ex. 1.2.5 --> 1.3.0
  • Examples of minor changes are: service internals, non-shared code and libraries, important bug fixes.
• BUG FIXES impact the BUILD version number. Ex. 1.4.2 --> 1.4.3
  • Examples are small bug fixes that do not affect other components

Release Best Practices¶

When/Why releasing a module?¶

• Generally speaking a developer should release a module when the code is mature enough to be used by others.
• An early release should be available in case others are relying on a module that is currently under heavy development (i.e., frequent commits that imply frequent snapshot updates), in order to avoid blocking other development activities.
• Before updating an interface (e.g., service interfaces) or library (e.g., common and utilities modules) a developer MUST ENSURE there is a release of the current version.

How to release?¶

These are the steps for the release of a module, given that developer has a fresh checkout of the module to be released.

1. Add the following at the beginning of your @~/.m2/settings.xml:
   

   <servers>
    <server>
         <id>dnet4-releases</id>
         <username>your LDAP username</username>
         <password>your LDAP password</password>
      </server>
   </servers>
   

2. Add the SCM info (change {project.name} with the actual name of the project):
   

   <scm>
      <developerConnection>scm:svn:https://svn.driver.research-infrastructures.eu/driver/dnet40/modules/{project.name}/trunk</developerConnection>
   </scm>
   

3. Set the parent to a released parent. Example:
   

   <parent>
      <groupId>eu.dnetlib</groupId>
      <artifactId>dnet-parent</artifactId>
      <version>1.0.0</version>
   </parent>
   

4. Ensure there are no snapshots included as dependencies. Snapshot dependencies won't be resolved anymore by maven because released parents have visibility only on the released repository (dnet4-releases). For example, if your module currently depends on
   

   <dependency>
       <groupId>eu.dnetlib</groupId>
       <artifactId>cnr-misc-utils</artifactId>
       <version>[1.0.0-SNAPSHOT,2.0.0-SNAPSHOT)</version>
   </dependency>
   

   
   You should change the dependency as follows:
   

   <dependency>
       <groupId>eu.dnetlib</groupId>
       <artifactId>cnr-misc-utils</artifactId>
       <version>[1.0.0,2.0.0)</version>
   </dependency>
   

   
   Note that this implies that the dependency module (e.g. cnr-misc-utils) must have been released.
5. Run mvn release:prepare and answer the questions. Default answers are usually fine. This will:
   • copy your trunk into another svn folder (tags)
   • update the versions in trunk and tags
6. Run mvn release:perform. This will deploy the artifact on Nexus in the release repository dnet4-releases.

If you experience any issue, open a ticket to CNR or write to dnet-team@isti.cnr.it