CRaSH: the shell for the Java Platform

CRaSH
TH E SH EL L FOR TH E J AVA PL ATFOR M
S E P T E M B E R 2 0 1 3
@julienviet
@defrancea

www.exoplatform.com - Copyright 2012 eXo Platform 2
JULIEN VIET
− Contact
− julien@julienviet.com
− @julienviet
− http://github.com/vietj
− Open source for 10 years
− Official mission: deliver enterprise grade portal
server
− Marseille JUG Leader
− Involved in Java Community Process

WHAT IS EXO PLATFORM?
eXo Platform is an open
source social collaboration
software solution designed
for the Enterprise.
It is full featured, standard
based, extensible and has
an amazing design.
eXo Platform is featured in
Gartner's Magic Quadrant
for Horizontal Portal
Products 2012 as a User
eXperience Platform.

ALAIN DEFRANCE
− Contact
− defrancea@gmail.com
− @alaindefrance
− http://github.com/defrancea
− Open source for 3 years
− Contributed to open source projects like
Crash
− Marseille JUG Leader

BITTITAN
− SAAS Products
− MigrationWiz: Email migration
− SMTPLogic: SMTP gateway
− UserActivation: Easy onboarding to Office365
− Our blog
− http://blog.bittitan.com

CRASH PROJECT
− Latest stable 1.2
− Work in progress 1.3
− Licensed under LGPL
− Compatibility
− Java 6+
− Groovy 1.7+

KEY CONCEPTS
− Command Line Interface for JVM
− Create easily and quickly commands
− Compose commands into pipelines
− Connectors provide local or remote access

MODULAR DESIGN
− Core, connectors, plugins
− Only use what you need
− Memory
− Dependencies

CONNECTORS
− Defines shell interactions
− Asynchronous design
− Implemented by
− System.in / System.out
− Telnet
− SSH
− Web
− Attach

PLUGIN ARCHITECTURE
− Keep core small and lightweight
− New features without impacting core
− Current plugins
− Authentication: simple, jaas, key, crowd, …
− Languages: java, groovy, ruby, …
− Services: mail, cron, …

USER INTERFACE
− Interactive Real-Eval-Print-Loop
− SSH asynchronous execution
− Cron based execution (1.3)

POLYGLOT
− Leverage polyglot JVM ecosystem
− Groovy
− Commands
− REPL (1.3)
− Java
− Commands (1.3)
− Ruby work in progress

EXECUTION MODES
− Standalone
− Attach to a running JVM
− Embedded
− Servlet listener
− Spring
− Guice
− Grails
− VisualVM

BASE COMMANDS
− Covers JVM packages
− system
− jdbc
− jndi
− jmx
− Utilities: filter, sort, egrep, sleep

STANDALONE DEMO

JNDI/JDBC/JPA
ATTACH
DEMO

WRITING A COMMAND
public class mycommand {
@Command
@Usage(“the command”)
public void main(
@Usage(“foo option”)
@Option(names=[ “foo”]) String foo,
@Usage(“command arguments”)
@Argument List<String> args) {
…
}
}
% mycommand –foo the_option value1 value2

EMBEDDED
− Trivial to embed
− Programmatic
− Spring
− Guice
− Servlet listener
− Levels
− Embed
− Virtual file system

EMBEDDED BY

SPRING EMDEDDED
TWITTER COMMAND
DEMO

GIT LIKE COMMAND
public class git {
@Command
public void add(…) {…}
@Command
public void commit(…) {…}
…
}
% git add .
% git commit –m “feature implemented”

TYPES
− String, primitive types, enums
− Converter
− properties, jmx object name …
− Completer
− java.io.File
− system property name
− enums
− …

COMMAND PIPE
jmx find
ObjectName Map
jmx get sort

COMMAND PIPE
public class wc {
@Command
public PipeCommand<String, Integer>) main() {
return new PipeCommand<String, Integer>() {
int count = 0;
public void provide(String s) {
count += s.split(“n”).length;
}
public void close() {
context.provide(count);
}
}
}
}

JMX PIPE
DEMO

MAIL/CRON
DEMO

READ-EVAL-PRINT-LOOP
− Feature of 1.3
− Polyglot

REPL
DEMO

WRAP UP
− A multi facet, powerful and extensible tool
for all of us
− Try online : try.crashub.org
− Reach us at
− crashub.org
− @crashub
− crash-users@googlegroups.com

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