lunes, septiembre 12, 2011

Questa di Marinella è la storia vera Che scivolò nel fiume a Primavera Ma il vento che la vide così bella Dal fiume la portò sopra una stella (Canzone Di Marinella - Mina)

Most of us use Maven as a build automation tool. One of most important section are those related to dependencies. Typically projects have dependencies to external libraries like Spring, Hibernate, Slf4j, ... which are downloaded from External Maven Repository Servers like mvnrepository, ibiblio or from own Internal Maven Repository Server using JFrog or Nexus. This scenario but does not cover all possible cases.

It is uncommon that your project requires an external library that is not present in any repository, but can occurs, and in these cases are where you use company Internal Maven Repository to upload these artifacts. But this is not always possible, and typical example is when you are writing in a blog about a beta library and it is not present in any repository, and you want to add this library to pom file. Would be perfect if Maven could resolve these dependencies too without packaging them into project. So what can we do?

There are some alternatives:

- packaging .class files of external library into your project, so they are packaged as project files.
- asking library creators to upload Milestones to public repositories.
- create your own public Maven Repository.
- using GitHub?

Using GitHub, YES!!. You can configure your GitHub account as Maven Repository. In my case I always upload sample code to GitHub. Why not creating a GitHub project that acts as a Maven Repository and poms referencing to this repository?

Now I will summarize steps that shall be followed: (assuming that you have already created a project).
  1. Create a GitHub repository.
  2. Initialize local directory as Git repo.
  3. Modify project pom so distribution management tag points to local repository.
  4. Perform deploy goal so artifact is deployed to local repository.
  5. Push changes to GitHub.
  6. Nothing more. Now other project poms can use your repository.

Let's get down to work:

The first thing you should know is that the project I want to upload to Maven Repository is located at /media/share/workspace/github-test and project that will have a dependency will be located at /media/share/workspace/bar.

First step is creating a new GitHub repository. So login to your GitHub account and create a new repository. In my case I have named maven-repository.

Second step is initialize local directory as Git repository.

Third step is adding distributionManagement tag pointing to repository so when project is deployed, artifact is created to Git directory.

See that url tag is pointing to previously created Git directory (local disk).

Fourth Step is running mvn -DperformRelease=true clean deploy. Project is compiled, tested, and packaged. Now go to local repository and see what has appeared.

Fifth Step implies two operations, committing changes and pushing them to GitHub.

See that first command is adding root directory. Then all files are committed to local repository and pushed to GitHub repository.

Sixth Step if you want to call it step, is adding repository tag to project that requires published component. In our case bar project requires it.

This pom represents a project that wants to use github-test module. It is important to note that repository url is special (not showed when you explore GitHub projects with navigator), and is After repository name (in this case maven-repository) you should concatenate /raw/master. raw because you want to access to files without any decoration (no HTML), and master because it is the branch name.

When bar project is being compiled, github-test artifact is downloaded.

I think it is a good approach when you need to upload a Maven artifact temporally, or simply because your project requires a milestone version of artifact that is not uploaded into any repository.

I hope you like this post, and ... MOVE TO GIT.


5 comentarios:

Jens R dijo...

Really cool trick. Thanks sharing it.

Alex dijo...

Hi Jens thank you very much for reading my blog. I like that you found it useful.

Andreas Andreou dijo...

Hosting those to github is fine but if you expect the artifacts to be used by lots of ppl, it's much better to make sure they end up in the central maven repository.

There are a few ways to do that and i advice you to go over

Anónimo dijo...

Hi, interesting blog article. Unfortunately, github changed the raw URLs, now it is not that easy anymore.

Unknown dijo...

You can use as a repo.

It works for me