Overview of Maven and its concepts Maven, and the future of Maven 3.x Maven and its ecosystem Good and bad practices Usecases

1. Apache Maven – LorraineJUG
June 1st, 2010
Arnaud Héritier
eXo Platform
Software Factory Manager

2. Arnaud Héritier
• Software Factory Manager
eXo platform
» In charge of tools and methods
• Committer since 2004 and
member of the Project
Management Committee
• Coauthor of « Apache Maven »
published by Pearson (in French)
• Contact me :
» http://aheritier.net
» Twitter : @aheritier
» Skype : aheritier
2

3. Apache Maven
CHOOSE YOUR MENU

4. Overview
• Definition • Maven or not Maven,
History
•
that is the question !
• Concepts
» Conventions » Maven, the project
» POM choice
» Reactor and Modules » Maven, the corporate
» Inheritance
» Artifact Repository
choice
» Dependency » Competitors
» Version
» Profiles
» Build Lifecycle And Plugins
4

5. Back to the future
• Maven 2.x
• Maven 3.x
• Community
5

6. Ecosystem
• Repository Managers • Continuous Integration
• Quality Management • IDE
» Tests Automation » Eclipse
» Quality Metrics Reports » Idea IntelliJ
» Project Reports » Netbeans
» Sonar
6

7. Good & Bad Practices
• K.I.S.S.
• Project Organization
• POM
• Development
7

8. Usecases
• Secure your credentials
• Build a part of your project using reactor
options
• Automate your release process
» (at least the technical part)
• Setup a global mirror
8

9. Apache Maven
OVERVIEW

10. Definition
• Apache Maven is a software project
management and comprehension tool.
• Based on the concept of a project object model
(POM)
» Maven can manage a project's build, binaries,
reporting and documentation from a central piece of
information.
10

11. History
• Initiated
in 2001 by Jason Van Zyl in Alexandria,
an Apache Jakarta project,
• Moved to Turbine few months after,
• Became a Top Level Project in 2003.
• Maven 2.0 released in September 2005
• Maven 3.0 … coming soon !!!
11

12. Apache Maven
CONCEPTS
12

13. Conventions
• 1 project = 1 artifact (pom, jar, war, ear, …)
• Standardized
» project descriptor (POM)
» build lifecycle
» directories layout
• *.java to compile in
src/[main|test]/java
• *.xml, *.properties needed
in classpath and to bundle
in archive in src/[main|test]/resources
• target directory for generated stuffs (sources, classes, …)
• …
13

14. POM
• An XML file (pom.xml) <?xml version="1.0" encoding="UTF-8"?>!
<project>!
<modelVersion>4.0.0</modelVersion>!
<groupId>net.aheritier.samples</groupId>!
• Describing <artifactId>simple-webapp</artifactId>!
<version>1.1-SNAPSHOT</version>!
» Project identification <packaging>war</packaging>!
<name>Simple webapp</name>!
» Project version <inceptionYear>2007</inceptionYear>!
<dependencies>!
» Project description <dependency>!
<groupId>org.springframework</groupId>!
» Build settings <artifactId>spring-struts</artifactId>!
» Dependencies
<version>2.0.2</version>!
</dependency>!
» … ...!
</dependencies>!
</project>!
14

15. Reactor
• Split your project in
sub-modules <project>!
...!
• Maven computes the
<modules>!
build order from <module>moduleA</module>
!
dependencies <module>moduleB</module>
!
between sub- <module>moduleC</module>
!
modules. <module>moduleD</module>
!
<module>moduleE</module>
!
• Modules have to be <module>moduleF</module>
!
defined in the POM </modules>!
...!
» No auto-discovery for </project>!
performance reasons
15

16. Inheritance
• Share settings between
projects/modules
• By default the parent
project is supposed to
be in the parent
directory (../)
<parent>!
<groupId>net.aheritier.sample</groupId>!
<artifactId>my-parent</artifactId>!
<version>1.0.0-SNAPSHOT<version>!
</parent>!
16

17. Inheritance
Use a technical inheritance to organize sub-modules
Use assembly to package batchs
Insert README in all artifacts
Use clirr to validate backward compatibility
17

18. Artifact Repository
18

19. Artifact Repository
• By default Maven
downloads artifacts
required by the project
or itself from central
• Downloaded artifacts
are stored in the local
repository
• Used to store :
» Project’s binaries
» Project’s dependencies
» Maven and plug-ins
binaries
19

20. Dependencies
Without Maven With Maven
20

21. Dependencies
• Declaratives
» groupId + artifactId + version (+ classifier)
» Type (packaging) : jar, war, pom, ear, …
• Transitives
» Lib A needs Lib B
» Lib B needs Lib C
» Thus Lib A needs Lib C
21

22. Dependencies
• Scope
» Compile (by default) : Required to build and run the application
» Runtime : not required to build the application but needed at
runtime
• Ex : taglibs
» Provided : required to build the application but not needed at
runtime (provided by the container)
• Ex : Servlet API, Driver SGBD, …
» Test : required to build and launch tests but not needed by the
application itself to build and run
• Ex : Junit, TestNG, DbUnit, …
» System : local library with absolute path
• Ex : software products
22

23. Dependencies
• Define all dependencies you are using
» and no more !
• If you have optional dependencies
» Perhaps you should have optional modules instead
• Cleanup your dependencies with
» mvn dependency:analyze!
• Study your dependencies with
» mvn dependency:tree!
» mvn dependency:list!
23

24. Versions
• Project and dependency versions
• Two different version variants
» SNAPSHOT version
• The version number ends with –SNAPSHOT
• The project is in development
• Deliveries are changing over the time and are overridden
after each build
• Artifacts are deployed with a timestamp on remote repositories
» RELEASE version
• The version number doesn’t end with –SNAPSHOT
• Binaries won’t change
24

25. Versions
25

26. Versions
• About SNAPSHOT dependencies
» Maven allows the configuration of an update policy. The
update policy defines the recurrence of checks if there
is a new SNAPSHOT version available on the remote
repository :
• always
• daily (by default)
• interval:X (a given period in minutes)
• never
» Must not be used in a released project
• They can change thus the release also 
• The release plugin will enforce it 
26

27. Versions
• Range
» From … to …
» Maven automatically searches for the
corresponding version (using the update policy for
released artifacts)
» To use with caution
• Risk of non reproducibility of the build
• Risk of side effects on projects depending on yours.
27

28. Versions
• Usethe versions plugin to update all versions
of your project and its modules
mvn versions:set –DnewVersion=A.B.C-SNAPSHOT!
28

29. Profiles
• Allow to modify the default behavior of Maven
by overriding/adding some settings
• Use mvn help:active-profiles to debug
• Explicit activation or deactivation
mvn <phases or goals> !
-PprofileId1,-profileId2 !
-P!profileId3!
29

30. Profiles
● activeByDefault = If no other profile is activated
● Activation through Maven settings
<settings>!
...!
<activeProfiles>!
<activeProfile>profile-1</activeProfile>!
</activeProfiles>!
...!
</settings>!
30

31. Profiles
• Activation based on environment variables
<profiles>!
<profiles>!
<profile>!
<profile>!
<activation>!
<activation>!
<property>!
<property>!
<name>run-its</name>!
<name>!skip-enforce</name>!
<value>true</value>!
</property>!
</property>!
</activation>!
</activation>!
...!
...!
</profile>!
</profile>!
</profiles>!
</profiles>!
31

32. Profiles
• OS / Java settings
<profiles>!
<profile>!
<profiles>! <activation>!
<os>!
<profile>!
<name>Windows XP</name>!
<activation>!
<family>Windows</family>!
<jdk>[1.3,1.6)</jdk>!
<arch>x86</arch>!
</activation>!
<version>5.1.2600</version>!
...!
</os>!
</profile>!
</activation>!
</profiles>! ...!
</profile>!
</profiles>!
32

33. Profiles
• Activation on present or missing files
<profiles>!
<profile>!
<activation>!
<file>!
<missing>${project.build.directory}/generated-sources/
axistools/wsdl2java/</missing>!
</file>!
</activation>!
...!
</profile>!
</profiles>!
33

34. Build Lifecycle And Plugins
• Plugin based
architecture for a great
extensibility
• Standardized lifecycle
to build all types of
archetypes
34

35. Build Lifecycle And Plugins
Default Lifecycle Clean Lifecycle Site Lifecycle
validate pre-clean pre-site
initialize
clean site
generate-sources post-clean post-site
process-sources
site-deploy
generate-resources
process-resources
compile
process-classes
generate-test-sources
process-test-sources
generate-test-resources
process-test-resources
test-compile
process-test-classes
test
prepare-package
package
pre-integration-test
integration-test
post-integration-test
verify
install
deploy
35

36. Build Lifecycle And Plugins
• Many plugins
» Packaging
» Reporting
» IDE integration
» Miscellaneous tools integration
• Many locations
» maven.apache.org
» mojo.codehaus.org
» code.google.com
» …
Take care while selecting them !!!
36

37. Apache Maven
MAVEN OR NOT MAVEN,
THAT IS THE QUESTION !
37

38. Maven, the project’s choice
• Application’s architecture
» The project has the freedom to divide the application in
modules
» Maven doesn’t limit the evolution of the application
architecture
• Dependencies management
» Declarative : Maven automatically downloads them and
builds the classpath
» Transitive : We define only what the module needs itself
38

39. Maven, the project’s choice
• Centralizesand » Builds
automates all » Tests
development facets » Packages
(build, tests, releases) » Deploys
» Documents
• Onething it cannot do » Checks and reports
for you : to develop  about the quality of
developments
39

40. Maven, the corporate’s choice
• Widely adopted and known
» Many developers
• Developments are standardized
• Decrease of costs
» Reuse of knowledge
» Reuse of configuration fragments
» Reuse of process and code fragments
• Product quality improvement
» Reports and monitoring
40

41. Competitors
• Ant + Ivy, Easy Ant, Gant, Gradle, Buildr…
• Script oriented
» You can do what you want !
• Reuse many of Maven conventions (directories layout,
…) and services (repositories) but without enforcing
them
• The risk for them : Not being able to evolve due to the
too high level of customization proposed to the user.
» We tried on Maven 1 and it died because of that. It was
impossible to create a set of tests to cover all usages.
» It’s like providing a framework without public API 
41

42. With scripts oriented builds
You can have But often you have
(if you have good skills) (moreover after years …)
42

43. With Maven
We dream to deliver But today we have too often
(Maven 3.x) (Maven 2.x)
43

44. Apache Maven
BACK TO THE FUTURE

45. Apache Maven
PRODUCT
45

46. Apache Maven 2.0.x
• bugs fix
• Last release : 2.0.11
• No other release of 2.0.x in the future
46

47. Apache Maven 2.x
• Evolutions, new features
• Several important new features in 2.1 like
» Parallel downloads
» Encrypted passwords
» Reactor command line options
• Last release : 2.2.1
47

48. Apache Maven 3.x
• Do not be afraid !!!!!
• Full compatibility with maven 2.x projects
» Or at least at 99,99999%
• Availability in 2010 (2nd half)
48

49. Apache Maven 3.x – Why ?
» To build new foundations for the future
» The major part of the code was reviewed / rewritten
• How POMs are constructed
• How the lifecycle is executed
• How the plugin manager executes
• How artifacts are resolved
• How it can be embedded
• How dependency injection is done
• …
49

50. Apache Maven 3.x - robustness
• Error & integrity reporting
» Much improved error reporting where we will provide
links to each identifiable problem we know of. There are
currently 42 common things that can go wrong.
» Don't allow builds where versions come from non-
project sources like local settings and CLI parameters
» Don't allow builds where versions come from profiles
that have to be activated manually
• Backward compatibility
» Several thousands of integration tests
50

51. Apache Maven 3.x - performances
• Many optimizations
• New support of parallel builds of modules
• New incremental (partial) build
» To improve IDE integration
51

52. Apache Maven 3.x – new features
• Any-source POM
» If you don’t like XML, choose another DSL
• Versionless parent elements
» If you don’t use versions or release plugins to
automatically update them
• Mixins
» a compositional form of Maven POM configuration
• Global excludes
52

53. Apache Maven 3.x
• What it will change for maven developers ?
» Lifecycle extension points
» Plugin extension points
» Incremental build support
» Queryable lifecycle
» Extensible reporting
» Bye bye Plexus, welcome JSR 330 & Google Guice
» Well defined and documented APIs
53

54. Apache Maven 3.x – New tools
• mvnsh
» A cross-platform shell
dedicated to maven
• Tycho
» Maven ready for OSGI
and Eclipse
developments
54

55. In Apache Maven 3.0 ?
• A backward compatibility near to 100% for
projects and plugins
• A totally new implementation
» A greater robustness with a better reporting and
more readable logs
» Performances improvements and new parallel
builds
» A better integration for others tools like IDE or
continuous integration servers
• No change in current POM format
55

56. Apache Maven
COMMUNITY
56

57. Users Mailing List
• users@maven.apache.org • Blue :
» Traffic statistics cover a » Number of subscribers
total of 1697 days. • Red :
» Current subscribers: 1861 » Number of messages
» Current digest per day
subscribers: 47
» Total posts (1697 days):
80633
» Mean posts per day: 47.52
• http://pulse.apache.org/
57

58. Apache Maven Web Site
58

59. Dowloads
Per month downloads
http://people.apache.org/~vgritsenko/stats/
projects/maven.html
59

60. The team
• 60committers,
• More than 30 active in 2009,
• Several organizations like Sonatype, deliver
resources and professional support,
• A community less isolated : more interactions
with Eclipse, Jetty,
60

61. Commit Statistics
61

62. Apache Maven
ECOSYSTEM

63. Maven’s ecosystem
• Maven alone is nothing
• You can integrate it with many tools
» A large set of plug-ins is already available
» You can define your own plug-ins
63

64. Apache Maven
REPOSITORY MANAGERS
64

65. Repository Managers
• Basic services • Several products
» Search artifacts
» Browse repositories » Sonatype Nexus
» Proxy external repositories (replaced Proximity)
» Host internal repositories » Jfrog Artifactory
» Security » Apache Archiva
65

66. Secure your builds
• Deploy a repository manager to proxy externals
repositories to :
» Avoid external network outages
» Avoid external repository unavailabilities
» To reduce your company’s external network usage
» To increase the speed of artifact downloads
• Additional services offered by such servers :
» Artifacts procurement to filter what is coming from the
outside
» Staging repository to validate your release before
deploying it
66

67. Nexus at eXo for productivity
67

68. Nexus at eXo for collaboration
• Deploy 3rd Party
Artifacts
• Collaborate with
Internal Repositories
• Distribute to the
community with Public
Repositories
• Distribute
to
customers with Private
Repositories
68

69. Nexus at eXo for quality
• Ease the Burden on Central and others remote
repositories
• Gain Predictability and Scalability
• Control and Audit Dependencies and Releases
• Stage releases
69

70. Apache Maven
QUALITY MANAGEMENT
70

71. Tests Automation
• Use automated tests as often as you can
• Many tools are available through Maven
» JUnit, TestNG – unit tests,
» Selenium, Canoo – web GUI test,
» Fitnesse, Greenpepper – functional tests,
» SoapUI – web services tests
» JMeter – performances tests
» And many more frameworks are available to reply
your needs
71

72. Quality Metrics
• Extract quality metrics from your project and monitor
them :
» Code style (CheckStyle)
» Bad practices or potential bugs (PMD, FindBugs, Clirr)
» Tests coverage (Cobertura, Emma, Clover)
» …
• You can use blocking rules
» For example, I break the build if the upward compatibility of
public APIs is broken
• You can use reports
» Reports are available in a web site generated by Maven
» Or in a quality dashboard like Sonar
72

73. Dependency Report
73

74. Sonar, a quality dashboard
74

75. Sonar, analyze your project
75

76. Sonar, Continuous Improvement ?
76

77. Apache Maven
CONTINUOUS INTEGRATION
77

78. Continuous Integration
• Setup a continuous integration server to :
» Have a neutral and unmodified environment to run your
tests
» Quickly react when
• The build fails (compilation failure for example)
• A test fails
• A quality metric is bad
» Continuously improve the quality of your project and
your productivity
• Many products
» Hudson, Bamboo, TeamCity, Continuum, Cruisecontrol,
…
78

79. Hudson, how the weather is ?
79

80. Hudson : build, test, check
80

81. Apache Maven
IDE
81

82. Eclipse
• Integration from maven (eclipse:eclipse)
» Allow many customizations
» Support many versions/variants of eclipse
» Support many usages (ear …)
» Doesn’t support projects with “pom” packaging
» Few support from dev team
» Many bugs in classpath management
» Asynchronous
• You have to regenerate and reload project each time you
change a POM)
82

83. Eclipse
• Integration from eclipse (m2eclipse)
» Synchronous
» Nice UI and services to edit POMs
» Support projects with “pom” packaging
» Doesn’t support all usages like EAR with WTP
» Doesn’t support very well a large number of
modules
» Slow down eclipse on large projects because of a
lack of support of incremental build in Maven 2.x
and its plugins
83

84. Eclipse (m2eclipse)
84

85. Eclipse (m2eclipse)
85

86. Eclipse (m2eclipse)
86

87. Idea IntelliJ
87

88. Netbeans
88

89. Apache Maven
GOOD & BAD PRACTICES

90. Apache Maven
KISS
90

91. K.I.S.S.
• Keep It Simple, Stupid
• Start from scratch
» Do not copy/paste what you find without understanding
• Use only what you need
» It’s not because maven offers many features that you
need to use them
• Filtering
• Modules
• Profiles
• …
91

92. Apache Maven
PROJECT ORGANIZATION
GOOD & BAD PRACTICES
92

93. Project bad practices
93

94. Project bad practices
• Have too many modules
» Is there a good reason ?
• Technical constraint ?
• Team organization ?
» It increases the build time
• Many more artifacts to generate
• Dependencies resolution more complex
» It involves more complex developments
• More modules to import in your IDE
• More modules to update …
94

95. Project good practices
• Use the default
inheritance :
» The reactor project is
also the parent of its
modules.
» Configuration is
easier :
• No need to redefine SCM
settings, site distribution
settings …
95

96. Apache Maven
POM GOOD & BAD PRACTICES
96

97. POM bad practices
• Dependencies :
» DON’T confuse dependencies and
dependencyManagement
• Plugins :
» DON’T confuse plugins and pluginManagement
» DON’T use AntRun plugin everywhere
» DON’T let Maven choose plugins versions for you
97

98. POM bad practices
• Profiles :
» DON’T create environment dependant builds
» DON’T rely on dependencies coming from profiles
(there is no transitive activation of profiles)
• Reporting and quality
» DON’T activate on an existing project all reports
with default configuration
» DON’T control formatting rules without giving
settings for IDEs.
• DON’T put everything you find in your POM.
98

99. POM good practices
• Set versions of dependencies in project
parent’s dependencyManagement
• Set dependencies (groupId, artifactId, scope) in
each module they are used
• Use the dependency plugin (from apache) and
versions plugin (from mojo) to analyze, cleanup
and update your dependencies.
99

100. Apache Maven
DEVELOPMENT
GOOD & BAD PRACTICES
100

101. Development bad practices
• DON’T spend your time in the terminal,
• DON’T exchange libraries through emails,
• DON’T always use "-Dmaven.test.skip=true”
• DON’T manually do releases
101

102. Development good practices
• Keep up-to-date your version of Maven
» For example in 2.1 the time of dependencies/modules
resolution decreased a lot (Initialization of a project of
150 modules passed from 8 minutes to less than 1)
• Use the reactor plugin (Maven < 2.1) or native
reactor command line options (Maven >= 2.1) to
rebuild only a subpart of your project :
» All modules depending on module XXX
» All modules used to build XXX
• Try to not use Maven features not supported by
your IDE (resources filtering with the plugin
eclipse:eclipse)
102

103. Apache Maven
USECASES

104. Apache Maven
SECURE YOUR CREDENTIALS
104

105. Secure your credentials
 Generate a private key
-
arnaud@leopard:~$ mvn --encrypt-master-password toto
{dZPuZ74YTJ0HnWHGm4zgfDlruYQNda1xib9vAVf2vvY=}
● We save the private key in ~/.m2/settings-security.xml
<settingssecurity>!
<master>{dZPuZ74YTJ0HnWHGm4zgfDlruYQNda1xib9vAVf2vvY=}</master>!
</settingssecurity>!
105

106. Secure your credentials
● You can move this key to another drive ~/.m2/settings.xml
- <settingsSecurity>
<relocation>/Volumes/ArnaudUsbKey/secure/settings-security.xml</relocation>
</settingsSecurity>!
● You create an encrypted version of your server
password
- arnaud@mbp-arnaud:~$ mvn --encrypt-password titi
{SbC9Fl2jA4oHZtz5Fcefp2q1tMXEtBkz9QiKljPiHss=}!
● You register it in your settings
- <settings>
...
<servers>
...
<server>
<id>mon.server</id>
<username>arnaud</username>
<password>{SbC9Fl2jA4oHZtz5Fcefp2q1tMXEtBkz9QiKljPiHss=}</password>
</server>
...
</servers>
...
</settings>!
106

107. Apache Maven
BUILD A PART OF YOUR PROJECT
107

108. Using Reactor Options
• Options added in maven 2.1
• Available in 2.0.x with the maven-reactor-plugin
» But syntax is longer
• Allow to control what you want to build in your
project
108

109. Using Reactor Options
- arnaud@mbp-arnaud:~$ mvn install
[INFO]
------------------------------------------------
[INFO] Reactor Summary:
[INFO]
[INFO] Project ....................... SUCCESS
[2.132s]
[INFO] ModuleA ....................... SUCCESS
[5.574s]
[INFO] ModuleB ....................... SUCCESS
[0.455s]
[INFO] ModuleC ....................... SUCCESS
[0.396s]
[INFO] ModuleD ....................... SUCCESS
[0.462s]
[INFO] ModuleE ....................... SUCCESS
[0.723s]
[INFO] ModuleF ....................... SUCCESS
[0.404s]!
 Builds everything from A to F
109

110. Using Reactor Options
- arnaud@mbp-arnaud:~$ mvn install –pl
moduleE,moduleB
[INFO] -------------------------------------------
[INFO] Reactor Summary:
[INFO]
[INFO] ModuleB .................. SUCCESS [2.774s]
[INFO] ModuleE .................. SUCCESS [1.008s]
 Builds only modules B and E
 Following dependencies order
 -pl --project-list: Build the
specified reactor projects instead
of all projects
110

111. Using Reactor Options
- arnaud@mbp-arnaud:~$ mvn install –pl moduleD -am
[INFO] ------------------------------------------
[INFO] Reactor Summary:
[INFO]
[INFO] ModuleA ................. SUCCESS [4.075s]
[INFO] ModuleB ................. SUCCESS [0.468s]
[INFO] ModuleC ................. SUCCESS [0.354s]
[INFO] ModuleD ................. SUCCESS [0.384s]
 Builds module D (-pl) and all
modules it uses as dependencies
 -am --also-make: If a project list
is specified, also make projects
that the list depends on
 Usecase : Build all modules
required for a war, ear, …
111

112. Using Reactor Options
- arnaud@mbp-arnaud:~$ mvn install –pl moduleD -amd
[INFO] ------------------------------------------
[INFO] Reactor Summary:
[INFO]
[INFO] ModuleD ................. SUCCESS [4.881s]
[INFO] ModuleE ................. SUCCESS [0.478s]
[INFO] ModuleF ................. SUCCESS [0.427s]
 Builds module D (-pl) and all
modules which depend on it
 -amd --also-make-dependents: If
a project list is specified, also
make projects that depend on
projects on the list
 Usecase : Check that a change in
a module didn’t break others
which are using it
112

113. Using Reactor Options
- arnaud@mbp-arnaud:~$ mvn install –rf moduleD
[INFO] ------------------------------------------
[INFO] Reactor Summary:
[INFO]
[INFO] ModuleD ................. SUCCESS [9.707s]
[INFO] ModuleE ................. SUCCESS [0.625s]
[INFO] ModuleF ................. SUCCESS [0.679s]
[INFO] Project ................. SUCCESS [2.467s]
 Restarts all the build from module
D (-rf)
 -rf,--resume-from <arg> :
Resume reactor from specified
project
 Usecase : The build failed a 1st
time in module D, you fixed it, and
restart the build were it was to end
it.
113

114. Apache Maven
RELEASE YOUR PROJECT
114

115. Release of a webapp in 2002
• Limited usage of eclipse
» No WTP (Only some features in WSAD),
» No ability to produce WARs
115

116. Release of a webapp in 2002
• Many manual tasks
» Modify settings files
» Package JARs
» Copy libraries (external and internal) in a « lib »
directory
» Package WAR (often with a zip command)
» Tag the code (CVS)
» Send the package on the integration server using
FTP
» Deploy the package with AS console
116

117. Release of a webapp in 2002
• Oneproblem : The are • How long did it take ?
always problems » When everything is ok :
» Error in config files 15 minutes
» Missing dependencies » When there’s a
» Missing file problem : ½ day or
» Last minute fix which created a bug more
» And many other possibilies ..
117

118. Maven Release Plugin
• Automates the release process from tagging
sources to binaries delivery
• Release plugin main goals:
» Prepare : To update maven versions and
information in POMs and tag the code
» Perform : To deploy binaries in a maven repository
• After that you can just automate the deployment
on the AS using cargo for example.
118

119. Maven Release Plugin
119

120. Configuration and Prerequisites
• Project
version (must be a SNAPSHOT version)
• Dependencies and plugins versions mustn’t be
SNAPSHOTs
120

121. Troubleshooting Releases
• Common errors during release:
» Build with release profile was tested before and fails
» Local modifications
» Current version is not a SNAPSHOT
» SNAPSHOTs in dependencies and/or plugins
» Missing some configuration (scm, distribMgt, …)
» Tag already exists
» Unable to deploy project to the Repository
» Connection problems
121

122. SCM configuration
SCM binaries have to be in the PATH
SCM credentials have to already be stored or you
have to pass them in command line with :
–Dusername=XXX –Dpassword=XXX
<scm>!
<connection>scm:svn:http://svn.acme.com/myproject/trunk</connection>!
<developerConnection>scm:svn:https://svn.acme.com/myproject/trunk</developerConnection>!
<url>http://fisheye.acme.com/browse/myproject/trunk</url>!
</scm>!
122

123. Distribution Management
• Where you want to upload released binaries
» The url of a repository dedicated for your project/
corporate maven deliveries in your repository manager
<project>!
<distributionManagement>!
<repository>!
<id>repository.acme.com</id>!
<url>${acme.releases.repo.url}</url>!
This id will be used in user’s
</repository>!
maven settings
. . .! (~/.m2/settings.xml)
</distributionManagement>!
. . . !
<properties>!
<acme.releases.repo.url>http://repo.acme.com/acme-releases</acme.releases.repo.url>!
. . .!
</properties>!
</project>!
Often useful to have a property
to test the release process on a
fake repository, to validate a
repo manager ...
123

124. Repository credentials
• One server entry is required per different repository id in
distribution management of projects
• In a corporate environment, use a unique id for all
repositories hosted on repository managers using same
credentials (corporate LDAP …)
<settings>!
...!
<servers>!
<server>!
<id>repository.acme.com</id>!
<username>aheritier</username>! This id is the one defined in
<password>{ABCDEFGHIJKLMNOPQRSTUVWYZ}</password>! distributionManagement entry of
</server>! the project to release
...!
</servers>!
...!
</settings>!
124

125. Default Release Profile in Super POM
• This profile is used when you generate binaries of
the release with “mvn release:perform”
• By default, generates sources and javadocs jars for
each module.
<profile>!
<id>release-profile</id>!
<activation>!
<property>!
<name>performRelease</name>!
<value>true</value>! This activation could be used in
</property>! profiles you want to activate in
</activation>! the release process
<build>!
<plugins>!
...!
</plugins>! Configuration to generate
</build>! sources and javadoc jars with
</profile>! basic setting
125

126. Custom release profile
<project>!
...!
<build>!
<pluginManagement>!
<plugins>!
<plugin>!
<groupId>org.apache.maven.plugins</groupId>!
<artifactId>maven-release-plugin</artifactId>!
<version>2.0</version>!
<configuration>!
<useReleaseProfile>false</useReleaseProfile>!
<releaseProfiles>myreleaseprofile</releaseProfiles>! Don’t use the default profile
</configuration>!
</plugin>! Use our customized profile
</plugins>!
</pluginManagement>!
</build>!
...!
<profiles>!
<profile>!
<id>myreleaseprofile</id>!
<build>! Our customized profile
...!
</build>! Customize the behavior of
</profile>!
</profiles>!
the build for a release
...! Take care to test is before
</project>! the release !!
126

127. Apache Maven
SETUP A GLOBAL MIRROR
127

128. Why should we setup a global mirror ?
• To simplify users and projects settings
• To control where binaries are coming from
» To not rely on project’s repositories
» To use only the corporate repository manager
• To improve build performances
» By reducing the number of requests to find a
missing artefact
128

129. How should we setup a global mirror ?
<setting>
<mirrors>
<mirror>
<id>global-mirror</id>
<mirrorOf>external:*</mirrorOf>
<url>http://repo.acme.com/public</url>
</mirror>
Send all requests to this url
</mirrors>
<profiles>
<profile>
<id>mirror</id>
<repositories>
<repository>
<id>central</id>
<url>http://central</url>
<releases><enabled>true</enabled></releases>
Use « central » id to override
<snapshots><enabled>true</enabled></snapshots> default maven configuration
</repository>
</repositories> Enable snapshots
<pluginRepositories>
<pluginRepository>
<id>central</id>
<url>http://central</url>
<releases><enabled>true</enabled></releases>
<snapshots><enabled>true</enabled></snapshots>
</pluginRepository>
</pluginRepositories>
</profile>
</profiles>
<activeProfiles>
<activeProfile>mirror</activeProfile>
</activeProfiles>
</settings> ! make the profile active all the
time
129

130. Apache Maven
CONCLUSION
130

131. Conclusion
• Today, Maven is widely adopted in corporate
environments,
• It provides many services,
• It has an important and really active community of
users and developers
• Many resources to learn to use it and a
professional support are available
• A product probably far from being perfect but on
rails for the future. Maven 3.0 is a new start.
• Many things to do
» We need you !
131

132. Apache Maven
QUESTIONS ?
132

133. Licence et copyrights
• Photos and logos belong to their respective
authors/owners
• Content under Creative Commons 3.0
» Attribution — You must attribute the work in the manner specified
by the author or licensor (but not in any way that suggests that they
endorse you or your use of the work).
» Noncommercial — You may not use this work for commercial
purposes.
» Share Alike — If you alter, transform, or build upon this work, you
may distribute the resulting work only under the same or similar license
to this one.
• http://creativecommons.org/licenses/by-nc-sa/3.0/us/
133

134. Apache Maven
TO GO FURTHER …

135. Apache Maven
DOCUMENTATIONS
135

136. Some links
• The main web site :
» http://maven.apache.org
• Project’s team wiki :
» http://docs.codehaus.org/display/MAVEN
• Project’s users wiki :
» http://docs.codehaus.org/display/MAVENUSER
136

137. Books
• NicolasDe loof
Arnaud Héritier
» Published by Pearson
» Collection Référence
» Based on our own
experiences with
Maven.
» From beginners to
experts.
» In French only
137

138. Books
• Sonatype / O’Reilly :
» The Definitive Guide
» http://
www.sonatype.com/
books
» Free download
» Available in several
languages
138

139. Books
• Exist Global
» Better builds with
Maven
» http://
www.maestrodev.com/
better-build-maven
» Free download
139

140. Apache Maven
SUPPORT
140

141. Support
• Mailing lists
» http://maven.apache.org/mail-lists.html
• IRC
» irc.codehaus.org - #maven
• Forums
» http://www.developpez.net/ forum maven
» In French
• Dedicated support
» Sonatype and many others companies
141