[Maven 2] Repositories

larrin 2007-04-13

展开全文

$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./maven2/
  - Mirrors
    - http://mirrors./maven2/
    - http://public./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./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