[Maven 2] Repositories

$Revision: 1.9 $	$Name: $	$Date: 2006/04/13 13:54:09 $	Working with maven 2
$Source: /ppw/training/maven/repository/maven2/src/html/repositories.html,v $

Where Do All the Goodies Come From?

• Things maven needs are downloaded JIT
  • Plugins
  • Dependencies for projects
  • …
• From remote repositories on the ‘net
• Cached in a local repository
  • ~/.m2/repository/

Remote Repositories

• Many repositories
  • Central repository
    • Under control of the maven team
    • Contains all known Java artifacts that they are allowed to distribute
      • Could not be served by Apache because of Apache license politics
    • http://www.ibiblio.org/maven2/
    • Mirrors
      • http://mirrors.dotsrc.org/maven2/
      • http://public.planetmirror.com/pub/maven2/
    • ibiblio is constantly under strain (servers, bandwith)
      • Mirrors are not really fast either
      • Request not to rsync central
      • Special maven-proxy exists
  • 3th party repositories
    • Some providers choose to distribute their artifacts themselves
  • Company-local repositories
    • Own artifacts
    • Private artifacts (access protection)
    • Missing artifacts
      • License issues (access protection)
      • Obscure artifacts
      • Solution to artifact naming problems
• Repositories can be accessed via any protocol supported by Wagon
  • HTTP, HTTPS, FTP, SFTP, SCP, WebDAV, …
    • In principle …
    • HTTP and HTTPS validated by the author
      • HTTPS issue: self-signed certificates
      • Can be configure to do authentification
• Our artifacts are also deployed to remote repositories for others to use
  • Private company release repository
    • Seperate snapshot repository: don‘t annoy other people with development versions
  • Public company release repository
  • Central repository

Typical setup

In practice, at PeopleWare

Project Server Layout

/	server in DMZ
|-- ppw/ | |-- projects/
| | |-- dgt/	directory per client
| | | |-- cvs_repository/	CVS repository root; access via ssh only
| | | | |-- CVSROOT/...
| | | | |-- OSMOT/... | | | | |-- OSMOT2/... | | | | |-- expertPoll/... | | | | `-- expertPollWebapp/...	module per project
| | | |-- public_html/	project web home
| | | | |-- .htaccess	access only for PeopleWare staff and client staff
| | | | |-- index.html | | | | |-- installation.html | | | | |-- contact.html | | | | . | | | | . | | | | .	information for the client
| | | | |-- developer/ | | | | | |-- OSMOT/... | | | | | |-- OSMOT2/.. | | | | | |-- expertPoll/... | | | | | `-- expertPollWebapp/...	maven generated project sites
| | | | `-- maven_repository/ | | | | `-- be/ | | | | `-- peopleware/ | | | | `-- dgt/ | | | | |-- OSMOT/ | | | | | |-- 1.0.0/... | | | | | . | | | | | . | | | | | . | | | | | | | | | |-- OSMOT2/... | | | | |-- expertPoll/... | | | | `-- expertPollWebapp/...	maven release repository for this client
| | | `-- share/ | | | |-- public/...	smb; non-version controlled, private material
| | . . | | . . | | . . . | . |-- sysadmin/... . `-- training/...

• un*x group per client

Configuring Which Repositories to Use

• Most often project-related
  • All developers for a project need same setup
  • Project dependent settings go in pom.xml
• Authentification depends on particular user
  • Access settings (username, password) go in ~/.m2/settings.xml <servers />-element
• Setting up Multiple Repositories

Configuring Mirrors

• Depends on particular user
  • User-dependent settings go in ~/.m2/settings.xml <mirrors />-element
• Using Mirrors for Repositories

Configuring HTTP Proxies

• Depends on particular user
  • User-dependent settings go in ~/.m2/settings.xml <proxies />-element
• Configuring a proxy

Repository Layout

• Directory structure based on groupId
  • s/\./\//
  • Like Java package structure
  • Suggestion to use reverse domain name of issuing entity as part of groupId
    • Like Java package names
  • E.g., groupId=be.peopleware.training.maven2
    • be/peopleware/training/maven2/
• artifactId
  • be/peopleware/training/maven2/helloWorld/
• version
  • be/peopleware/training/maven2/helloWorld/1.2.3/
• Everything for this artifact/version in this directory
  • Artifact
    • be/peopleware/training/maven2/helloWorld/1.2.3/helloWorld-1.2.3.jar
  • Consolidated POM
    • be/peopleware/training/maven2/helloWorld/1.2.3/pom.xml
  • Potentially other assemblies
    • E.g., source zip
  • Checksums for each file
    • MD5
• Have a look at central

Abberations

Maven 1 legacy

• Directory structure based on groupId is new since maven 2
• To be backward compatible, old maven 1 structure is kept too
  • E.g., Apache Jakarta Commons
    • groupId=commons-XXX
    • groupId=org.apache.… ???
  • E.g., Hibernate
    • groupId=hibernate (Hibernate 1-3)
    • groupId=net.sf.hibernate (Hibernate 1-2)
    • groupId=org.hibernate (Hibernate 3)
• Migration is in progress

Standard Sun Specification API‘s

• Package javax.…
• Naming convention
  • Legacy issues
• Some cannot be stored in public repository because of licensing issues
  • Only POM in central
  • Says where to download artifact
  • E.g., javax.mail

    • […]            <distributionManagement>            <downloadUrl>http://java.sun.com/products/javamail/downloads/index.html</downloadUrl>            </distributionManagement>            […]            

• Company missing-artifacts repository
  • Download artifact from given location
  • Install in company missing-artifacts repository, with POM, checksum

Local Installation

Try-out You‘re Own Stuff Locally First

• Run mvn install
  • Last-but-one phase in default build lifecycle
• Artifact is added correctly to local repository
  • With POM
  • With checksum

Solve Repository Problems

• Install artifacts in his local repository directly
• Do it by hand, or
• maven-install-plugin:install-file

  • mvn install:install-file -DgroupId=group-id         -DartifactId=artifact-id         -Dversion=version         -Dpackaging=packaging         -Dfile=fileToInstall        

  • Copies the fileToInstall into the local repository, in the directory structure based on group-id, with file name artifcact-id-version.packaging
• You should provide a POM and checksum too (by hand for now)
• Bad practice in a group effort
  • The problem you are having, other people will encounter too
  • Better do it in a company repository from the start

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This work is licensed under a Creative Commons Attribution 2.0 Belgium License.

Jan Dockx PeopleWare n.v., © 2005