The ABCs of Distributing Android Libraries

ABCDistributionFeatureBintray’s central repositories, JCenter and Conan-Center, are binary hubs for public OSS Maven and Conan (C++) packages respectively. They offer a great channel to distribute your public OSS packages. Having been around for a while, JCenter has become one of the most comprehensive sources for public OSS Maven packages, and is the channel-of-choice for many Maven projects. So we weren’t surprised to discover this blog post that describes how easy it is to distribute Android libraries through Bintray and JCenter.

Distributing Android libraries (or any other Maven package for that matter) through JCenter has its advantages. As one of the most popular Maven hubs, it exposes your package to a huge audience, and yet, you retain full ownership and can control how your package evolves. Basically, you upload your package to one of your public Maven repositories and ask for it to be included in JCenter. Once approved by the Bintray team, your package will be searchable on JCenter and freely available for download. You can learn about the details in the blog or look it up in the Bintray User Manual.

So if you’re ready to give your package world-wide fame, go ahead and open an account on Bintray. Bear in mind that since JCenter is a curated repository with trusted content, you need to be on a fully registered OSS or Premium account (as opposed to being on a trial) before you can link your package.

To start with a free OSS account, you can sign up here.

If you’re ready to go Premium (Pro or Enterprise), go here.

And if you want the full Enterprise experience, without committing to it yet, you can start a free trial (just remember to switch to an OSS or Premium account if you want to use JCenter).

Increase your Maven Package’s Exposure by Adding it to JCenter

If you already distribute your Maven packages via Bintray, your packages can gain further exposure by including them in Bintray’s JCenter! (if you are not very familiar with Bintray’s support for Maven, please refer to the user guide and to my previous post).

JCenter is the repository with the biggest collection of Maven artifacts in the world. And it’s on the best software distribution platform around – Bintray. This is where you want your Maven packages to be! CDN speed, user exposure, and live statistics to monitor the use of your artifacts are some of the benefits you get from JCenter. And if you really want to, you can also have your project synced with the older Maven Central repository.

Submit an Inclusion Request to JCenter

To promote sharing of packages within the developer community, once you have uploaded a package to one of your repositories, you can submit a request to the owner of any other repository to have your package included in theirs. If your request is granted, your package can be found just like any other package in that repository. You still maintain full control over the package in your own repository, and any changes you make to it, such as delivering new versions, or even removing it, are automatically synced to the other repository in which it’s included. So to maximize exposure of your Maven package in Bintray, all you need to do is request to have it added to JCenter.
In order to submit a request, just click on the ‘Add to JCenter’ button:

Add Package To JCenter
Once a Bintray moderator approves your request, your package will be available on JCenter, and you will receive a message into your Bintray mailbox. You will also see that your package is now linked to JCenter:
Maven Projects Linked To JCenter

Sync with Maven Central

At this point you can also have JCenter sync your package to Maven Central if you need to serve frameworks still using this repository. All you need to do is click on the ‘Maven Central’ link as shown above. Remember that you need to provide your Sonatype user name to Bintray before the syncing, but don’t worry, Bintray will remind you to do so if you haven’t already added it to your profile under Accounts:
Accounts Sonatype
Bintray takes care of the rest. Please also refer to the step by step instructions for how to sync your artifacts with Maven Central.

Good luck, and keep your package front and JCenter!

Publishing Your Maven Project to Bintray

Bintray gives you everything you need to share your Maven project, and much more: you will be able to monitor downloads and users with the statistics that Bintray keeps for you. You can also share your project via Bintray’s JCenter repository (which is the largest public Maven repository out there), and effortlessly sync it with Maven Central, if you wish.

Just follow these 5 simple steps to upload your Maven project to Bintray:

1. Have your Maven project ready

  • For this use case we will assume we have a maven project with the following groupId: org.jfrog.example.bintray.maven

2. Create a Maven package in Bintray

  • Open a Bintray account if you have not done so before.
  • Use the default Maven repository under your account or create a new one. The is where your Maven files will be hosted.

Create New Maven Repository

  • Under the Maven repository create a new package for your project. The package is merely a logical container that holds metadata about your project and annotates your files to allow Bintray to collect package and version level statistics.
    A good name for your package would be your main artifactId, but any name that logically identifies your project will do just as well.
    In our case, a good example would be: maven-example

3. Add the Bintray distribution URL

Next thing you need to do is to add a distribution section to your project’s pom.xml, and specify the URL from which to distribute your project. We will use our Bintray Maven repository and package as the target for deployment (remember? files in Bintray are always associated with a logical software package).

<distributionManagement>
  <repository>
      <id>bintray-repo-maven-example</id>
      <url>https://api.bintray.com/maven/tamarjfrog/maven-repo/maven-example/;publish=1</url>
  </repository>
</distributionManagement>

For your project to be visible to others, Bintray requires that you publish it. One way to do that is to add the publish directive to the distribution URL as a matrix parameter (;publish=1) as I did in the above example. You can also publish your projects at a later time using  the Bintray UI or via REST.

This block also includes an <id> tag. The id can be any string, but it should match the id in the settings.xml file described in the next step.

4. Provide your credentials to Bintray

In order to work with Bintray you need to provide your Bintray username and API Key as upload credentials in the username and password tags of your Maven settings.xml file. The API Key can be found when editing your Bintray profile page.

<server>
  <id>bintray-repo-maven-example</id>
  <username>tamarjfrog</username>
  <password>***my-top-secret-api-key***</password>
</server>

5. Time to deploy!

You are almost there. This is the time to run

mvn deploy

The project will be built, uploaded to the the Bintray repository target URL you provided, and published. You can now see your files in your Maven package in Bintray.

Maven Package Files List.
At this point, you can add your project to JCenter, the most comprehensive public Maven repository, so your project is well exposed. To read more about that, stay tuned for my next post.

A sample project similar to what I used in this post can be found in GitHub: bintray-examples/maven-examples.

Good Luck!

Download stats and logs – now with deep user insights

Ever wondered who exactly downloaded your software? I don’t mean just “someone from the United States.” I’m talking about getting down to the organization level in terms of “someone from Acme Corp. NY office”.

Now you can get this information, from Bintray:
Bintray Live Download Feed

This information is available for any package type for Bintray Premium users, but that’s not all. It is also available, for free, for every OSS package in JCenter!!! This means that if you own a package that is linked to JCenter you already have this information available today!

And not only can you get rich live logs of your downloads, you can retrieve fully parsable logs in CSV or Apache common format! Just use the REST API, or click the preferred log format link:
Bintray Download Logs

Log format options include the Apache-style logs, which can be analyzed by dozens of tools out there, or you can download the logs as CSV files. CSV files are usually easier to understand, and actually contain more data, such as ZIP code, geolocation etc. Download the CSV log and hack on! Or, you can even open it in Excel and show it to your boss:
Bintray Logs in CSV Format
Excel jokes aside, that’s the most powerful downloads analytics one can get and it’s there at your fingertips.

With Live Logs and Download Logs you get much more detail about activity within your repositories. This can be very helpful in analyzing peaks as it provides immediate feedback on the popularity of your software, and how this popularity is distributed by version, geo-location and organization. Naturally, it can also be used to direct you to where you should be focusing your marketing efforts.

It’s time to learn about your users!

Another one bites the Maven Central dust (and saved by Bintray)

Today, I encountered another very detailed blog post on the woes of publishing on Maven Central. Jose Maria Arranz (@jmarranz) explains why he doesn’t like Maven in general and publishing to Maven Central in particular (I am with him on a lot of valid points).

I can’t help quoting:

Fortunately when searching for how-to articles and commenting in Twitter, @jbaruch an employee of JFrog contacts with me offering Bintray.com alternative to publish to Maven Central, the people behind JCenter, I read the article “The easy way to maven central” and I was sold. Bintray provides a GUI to upload and self sign your artifacts if you provides your public and private GnuPG keys, and with a simple UI action you are published in JCenter repository, and providing the Sontaype user and password you can finally easily publish in Maven Central.

Bintray helped me to break the wall of Sonatype process. I’m saved!!

Currently I’ve released RelProxy on JCenter and Maven Central. For releasing I use Ant calling to Maven tasks to generate the required Maven artifacts and to generate a distribution zip with everything. Everything could be automated, I could add signing and uploading from Ant (or maybe by the POM) without Bintray, but Bintray auto-signing and uploading UI is enough for me, releasing is done from time to time and most of releasing process is already automated, and releasing in JCenter is a plus.

Note: Don’t forget JCenter, for instance Maven Central is no longer pre-configured in Google Android environment.

That’s what I call “success”!

Thanks for the kind words, Jose Maria! I am happy that we managed to help 🙂

Android Studio – Migration from Maven Central to JCenter

This post was originally published in Techno Talkative blog by Paresh Mayani. Feel free to comment here or there.

 

During the android workshop, in the office and in the chat with some of the android developers, I have received some questions around build script and repository:

  • Why earlier versions of android studio were using maven central?
  • Why android project, getting created using android studio, is using jcenter?
  • What are the reasons/benefits/purpose that android studio has gone with JCenter repository?
  • JCenter Vs. Maven Central

I had shared some of the points at that time, but I tried to go into the deep to know more about the migration made from maven central to jcenter. I have found interesting details from the couple of links:

Before going ahead and we discuss about the migration made from maven central to jcenter, here is brief about the repository (in case if you really don’t know!)

What is repository?

In Maven terminology, a repository is a place i.e. directory where all the project jars, library jar, plugins or any other project specific artifacts are stored and can be used by Maven easily.

In build.gradle file, you need to specify which repository to use when resolving dependencies for building your project, so you need to put something like the following in your build.gradle file:

repositories {
    jcenter()
}    

Yes, you need to specify at least one repository before you use any external dependency. Read more about Dependency Management Basics and repositories.

Maven central to jcenter migration

Now, here are the details and interesting points about the jcenter and the transition made from maven central to jcenter:

  • As said earlier, jcenter is the new default repository used with Android’s gradle plugin.
  • jcenter is a Java repository in Bintray, which is the largest repo in the world for Java and Android OSS libraries, packages and components.
  • All the content in jcenter is served over a CDN, with a secure https connection. Back in the time of the migration (Android Studio 0.8) The central maven 2 repository was HTTP only and HTTPS wasn’t supported. Reference: 51.6.2. Maven central repository. (This might be one of the reasons as Google is a fan of HTTPs!).
  • jcenter() is a superset of mavenCentral(), that encompasses many additional repositories and artifacts. Reference: Blog @ Bintray.
  • The jcenter guys claim, that they have a better performance than maven central.
  • Bintray has a different approach to package identification than the legacy Maven Central.
  • If you really need to get your package to Maven Central (for supporting legacy tools) you can do it from Bintray as well, in a click of a button or even automatically.

Regarding performance improvements, couple of android developer advocates had faced/noticed the issue of huge indexing with maven central.

In the words of Tor Norbye:

I ran AndroidStudio with a brand new settings directory, so it went and connected maven central and downloaded an index of the available artifacts.

Then I happened to look at the size of my directory.

My ~/Library/Cache/AndroidStudioPreview is 1.5G, and 1.2G of those are taken by the “Maven” subdirectory.

That’s ridiculous. We barely use the index at all. The primary use for it is the Dependency editor in the Project Structure Dialog, but we really don’t need to have a precomputed index for it. MavenCentral has a fast online JSON search we can use on demand when somebody searches for artifacts. In https://android-review.googlesource.com/#/c/94843/ we added a lint check which checks whether the dependencies are up to date, and the search for a handful of artifacts is near instant.

In short, we really don’t need the cache; it may help with code completion in .gradle and maven .pom files, but that’s not a super important usecase, and certainly not something *all* users should have to sacrifice 1.5G of download speed and diskspace to have the possibility of one day doing.

Read more on: The Maven index is *huge*!

I must say, after this migration from maven cetnral to jcenter, performance of the android studio is noticeable. Earlier loading android studio in even 4GB RAM configuration laptop, was all like:

code-21

Any way, this is not the ending of this study here, I still want to know more about the improvements or strong points (if any). If you know or have played enough with jcenter and maven central, please share your inputs. And also, as this is almost an undocumented point, I am really looking forward to hear about this migration, from the android developers advocates or engineers working in android tools team.