Nimble OSGi

So I just sent a rather cryptic twitter message with the instructions:

posh -kc "repos -l springdm;add org.springframework.osgi.samples.simplewebapp@active"

I figure it's probably worth a short note to explain what this is doing given the narrowband aspect of twitter communications.

This command is running an instance of the posh (sh)ell which ships with Nimble. There are two switch parameters parsed to the shell:

-c: Tells posh to execute the command passed in from the unix shell in the posh (sh)ell environment
-k: Tells posh to remain running after the command has completed and open a tty session for user input

Now we come to the actual commands:

repos -l springdm: tells posh to load the spring dm repository index into the nimble resolver

add org.springframework.osgi.samples.simplewebapp@active: tells nimble to resolve all dependencies for the spring simplewebapp from it's configured repositories.

The interesting thing about nimble resolution is that it doesn't just figure out the bundles that need to be installed. It also figures out what state these bundles should be in. If you look at the bundles in the nimble container using the command lsb you will see that not only are all the bundles installed but certain key bundles have also been activated:

lsb
*nimble/com.paremus.util.cmds-1.0.4.jar                           00:00    59Kb
0  ACTIVE    org.eclipse.osgi:3.5.1.R35x_v20090827
1  ACTIVE    com.paremus.posh.runtime:1.0.4
2  ACTIVE    com.paremus.posh.shell:1.0.4
3  RESOLVED  com.paremus.util.types:1.0.4
4  ACTIVE    com.paremus.nimble.core:1.0.4
5  ACTIVE    com.paremus.nimble.repos:1.0.4
6  ACTIVE    com.paremus.nimble.cli:1.0.4
7  RESOLVED  javax.servlet:2.5.0.v200806031605
8  RESOLVED  com.springsource.slf4j.api:1.5.6
9  RESOLVED  com.springsource.slf4j.nop:1.5.6
10  RESOLVED  com.springsource.net.sf.cglib:2.1.3
11  RESOLVED  com.springsource.edu.emory.mathcs.backport:3.1.0
12  RESOLVED  org.springframework.osgi.log4j.osgi:1.2.15.SNAPSHOT
13  RESOLVED  com.springsource.org.aopalliance:1.0.0
14  RESOLVED  org.springframework.osgi.jsp-api.osgi:2.0.0.SNAPSHOT
15  RESOLVED  com.springsource.slf4j.org.apache.commons.logging:1.5.6
16  RESOLVED  osgi.cmpn:4.2.0.200908310645
17  RESOLVED  org.mortbay.jetty.util:6.1.9
18  RESOLVED  org.springframework.osgi.jstl.osgi:1.1.2.SNAPSHOT
19  RESOLVED  org.springframework.core:2.5.6.A
20  RESOLVED  org.springframework.osgi.commons-el.osgi:1.0.0.SNAPSHOT
21  RESOLVED  org.mortbay.jetty.server:6.1.9
22  ACTIVE    org.springframework.osgi.samples.simplewebapp:0.0.0
23  RESOLVED  org.springframework.beans:2.5.6.A
24  RESOLVED  org.springframework.osgi.io:1.2.0
25  RESOLVED  org.springframework.osgi.jasper.osgi:5.5.23.SNAPSHOT
26  RESOLVED  org.springframework.aop:2.5.6.A
27  RESOLVED  org.springframework.osgi.catalina.osgi:5.5.23.SNAPSHOT
28  RESOLVED  org.springframework.context:2.5.6.A
29  ACTIVE    org.springframework.osgi.catalina.start.osgi:1.0.0
30  RESOLVED  org.springframework.osgi.core:1.2.0
31  RESOLVED  org.springframework.web:2.5.6.A
32  RESOLVED  org.springframework.osgi.web:1.2.0
33  ACTIVE    org.springframework.osgi.web.extender:1.2.0
34  ACTIVE    com.paremus.posh.readline:1.0.4
35  ACTIVE    com.paremus.util.cmds:1.0.4

This listing also demonstates another key feature of nimble. Typing lsb resulted in the following log line:

*nimble/com.paremus.util.cmds-1.0.4.jar                           00:00    59Kb

This demonstrates that the nimble container resolved the lsb command from its repository index and installed it on the fly. In fact if you look at the Nimble download it is only 55K in size. All of the extra functionality is automatically downloaded based on information provided via the nimble index files and traversing package and service level dependencies!

To complete this blog post you can browse the simple web app running from nimble by opening:

http://localhost:8080/simple-web-app/

Nimble is available for download here.