maven best practices

8/11/2019 Maven Best Practices

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Apache Maven:Best Practices

Brett Porter - [email protected]

http://www.devzuz.org/blogs/bporter
http://www.devzuz.org/blogs/bporterhttp://www.devzuz.org/blogs/bporterhttp://www.devzuz.org/blogs/bporterhttp://www.devzuz.org/blogs/bportermailto:[email protected]:[email protected]


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Maven without the PAIN

Sometimes unpleasant

You know its for your own good!

Can avoid or alleviate the problems

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3

Apache Maven

developer since 2003

Started the Archiva

project

Co-founder of

DevZuz

Co-author of

Better Builds with Maven

Who am I?


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Getting Ready for Maven

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Why are you using Maven?

Consider this from the beginning

Right tool for the job

Ensure you reap the benefits

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Preparing Your EnvironmentPlanning Ahead

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Development Environment

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Maven is best used in the bigger picture

Plan for the infrastructure you will use

...

...

...

...

...


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Automated Build Servers

Maven is intended to be automated

More than continuous integration

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Repository Management

Centralise storage of artifacts

Store the artifacts you build

Store third-party artifacts you consume

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Repository Servers

Can start with a simple storage

Servers can help manage the artifacts

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Using Repositories

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apache-snapshots Apache Snapshots Repository

http://people.apache.org/repo/m2-snapshot-repository

false

java-net-m1 Java.net Repository

http://download.java.net/maven/1/

legacy false


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apache-snapshots Apache Snapshots Repository

http://people.apache.org/repo/m2-snapshot-repository

false

java-net-m1 Java.net Repository

http://download.java.net/maven/1/

legacy false

codehaus-snapshots Codehaus Snapshots Repository

http://snapshots.repository.codehaus.org/

false

apache-releases Apache Releases Repository

http://people.apache.org/repo/m2-ibiblio-rsync-repository

false

codehaus-releases

Codehaus Releases Repository

http://repository.codehaus.org/

false

Using Repositories

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java-net-m2

Java.net Repository http://download.java.net/maven/2/

false

X


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Using Repositories

Minimise the number of repositories

Only in the POM if you redistribute

Use repository manager to centralise

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Locking Down

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archiva-snapshots-apache

http://reposerver/archiva/repository/snapshots/ apache.snapshots

archiva-snapshots-codehaus http://reposerver/archiva/repository/snapshots/

codehaus.snapshots

...

archiva-default

http://reposerver/archiva/repository/internal/ *
http://localhost:7777/archiva/repository/internal/http://localhost:7777/archiva/repository/internal/http://localhost:7777/archiva/repository/snapshots/http://localhost:7777/archiva/repository/snapshots/http://localhost:7777/archiva/repository/internal/http://localhost:7777/archiva/repository/internal/http://localhost:7777/archiva/repository/snapshots/http://localhost:7777/archiva/repository/snapshots/http://localhost:7777/archiva/repository/snapshots/http://localhost:7777/archiva/repository/snapshots/


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Settings and Installation

Three levels of configuration

project (pom.xml)

user (~/.m2/settings.xml)installation (/conf/settings.xml)

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Creating New ProjectsKeeping it Simple16


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Archetypes

Create new projects quickly

Standard project layouts

Include organisational POM

Facilitates consistency

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Writing the POM

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Write the build like you write code

Utilise conventions

Use multiple modules


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Inheritance

Multi-module inheritance

org.apache.maven maven

2.1-SNAPSHOT

maven-core

Organisational POM hierarchy

org.apache

apache

3

org.apache.maven

maven

2.1-SNAPSHOT

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Dependencies

Specify only what you need

Specify scope

Use dependencyManagementto:

coerce Maven to use a particular version

enforce consistency within a project

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Build Pipeline

Depends on your team

Use profiles for controlling complexity

Applies to testing as well

Key is to keep the build fast

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Scripting

Maven is declarative by design

Integrate scripting if necessary

Consider writing plugins


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Documenting as You GoThe D Word23


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Documentation

Document the build

Developer documentation

separate from product documentation

keep it together with reports

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Sites and Reports

A whole other topic of best practices!

But apply the same principles

set up what youll actually use

set up enforcement checks, not just reports

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Playing with OthersPortability26


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The Goal

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When a new developer builds the project

it works first go

... and it keeps working


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maven.test.skipis evil


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Hard Coding

Dont hard code paths

Dont hard code databases

Dont hard code properties

Dont do it in the testseither

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Profiles

Very useful - but dont abuse them

Document them all

Avoid depending on the environment

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Portable Artifacts

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Xvalue="org.hsqldb.jdbcDriver"value="jdbc:hsqldb:database"


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Portable Artifacts

Artifacts in repository must be unique

Either by classifier, or being portable

Recommend externalising configuration

database

target environmentproperties

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}${Resource Filtering

Use with great care!

Centralisation, not substitution!google.analytics.code=UA-1234567-1

X database.password=reallysecretpword

Useful for once-off alterations

Consider externalising configuration

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Shared Resources

Dont duplicate resources across projects

ZIP and put in the repository

Use the dependency plugin to retrieve

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Ensuring Reproducible BuildsReproducibility35


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Reproducibility

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Important for releases

More important for source releases

Build must be isolated from change

Portability is a pre-requisite


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The Enforcer

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org.apache.maven.plugins maven-enforcer-plugin

1.0-alpha-4

enforce

true

true

...


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The Enforcer

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org.apache.maven.plugins maven-enforcer-plugin

1.0-alpha-4

enforce

true

true

...

true

true


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The Enforcer

Help ensure build will be reproducible

Based on rules

force specific plugin versionsban snapshots

global exclusions

force Maven/Java/OS versioncan write your own

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Release Early, Often and RightReleasing40


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Releases

Set the project version to a -SNAPSHOT

Make them early and often

Use Maven tools to automate

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Brett Porter - [email protected]

Better Builds with Maven, blog at

http://www.devzuz.org/

Questions?
http://www.devzuz.org/http://www.devzuz.org/http://www.devzuz.org/mailto:[email protected]:[email protected]

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