MANIFEST.MF and feature.xml versioning rules

I'm forever forgetting what the rules are for dependency declarations in MANIFEST.MF and feature.xml for osgi plugins and features. And Googling often results in frustration rather than an answer. So, because today I actually found a concise list of the rules, I thought I'd repost them here, with some minor edits to help clarify.

OSGi Plugin Version Ranges

Dependencies on bundles and packages have an associated version range which is specified using an interval notation: a square bracket “[” or “]” denotes an inclusive end of the range and a round bracket “(” or “)” denotes an exclusive end of the range. Where one end of the range is to be included and the other excluded, it is permitted to pair a round bracket with a square bracket. The examples below make this clear.

If a single version number is used where a version range is required this does not indicate a single version, but the range starting from that version and including all higher versions.

There are four common cases:

• A “strict” version range, such as [1.2.3,1.2.3], which denotes that version and only that version.

• A “half-open” range, such as [1.2.3,2.0.0), which has an inclusive lower limit and an exclusive upper limit, denoting version 1.2.3 and any version after this, up to, but not including, version 2.0.0.

• An “unbounded” version range, such as 1.2.3, which denotes version 1.2.3 and all later versions.

• No version range, which denotes any version will be acceptable. NOT RECOMMENDED.

The complete text of the above snippet can be seen here (or here as PDF).

Example:

Require-Bundle: org.eclipse.core.runtime;bundle-version="[3.4.0,4.0.0)",
 org.eclipse.core.resources;bundle-version="[3.4.0,4.0.0)",
 org.eclipse.ui.ide;bundle-version="[3.4.0,4.0.0)",
 org.eclipse.ui.navigator;bundle-version="3.5.100",
 com.ibm.icu

See also:

• plugin manifest (plugin.xml)
• osgi bundle manifest (MANIFEST.MF)

---

In terms of feature manifest (feature.xml) rules, help.eclipse.org has pretty good documentation, but the most important thing to remember - and what I often have to look up - is how to state the matching rules for required upstream features & plugins. Experience says it's always better to state things explicitly so there's no downstream guesswork needed and anyone reading your manifest knows EXACTLY what version(s) are required for or compatible with your feature. Plus, while YOU might be using PDE UI to build, someone else might be using Tycho and Maven, and every tool can interpret missing metadata their own way.

When in doubt, spell it out.

Valid values and processing are as follows:

• if version attribute is not specified, the match attribute (if specified) is ignored.
• perfect - dependent plug-in version must match exactly the specified version. If "patch" is "true", "perfect" is assumed and other values cannot be set. [1.2.3,1.2.3]
• equivalent - dependent plug-in version must be at least at the version specified, or at a higher service level (major and minor version levels must equal the specified version). [1.2.3,1.3)
• compatible - dependent plug-in version must be at least at the version specified, or at a higher service level or minor level (major version level must equal the specified version). [1.2.3,2.0)
• greaterOrEqual - dependent plug-in version must be at least at the version specified, or at a higher service, minor or major level. 1.2.3

The complete text of the above snippet can be seen here.

Example:

<requires>
  <import feature="org.eclipse.m2e.feature" version="1.0.0" match="compatible"/>
  <import feature="org.maven.ide.eclipse.wtp.feature" version="0.13.0" match="greaterOrEqual"/>

  <plugin id="ch.qos.logback.classic" version="0.9.27.v20110224-1110" match="greaterOrEqual"/>
  <plugin id="ch.qos.logback.core" version="0.9.27.v20110224-1110" match="greaterOrEqual"/>
  <plugin id="ch.qos.logback.slf4j" version="0.9.27.v20110224-1110" match="greaterOrEqual"/>
  <plugin id="org.slf4j.api" version="1.6.1.v20100831-0715" match="compatible"/>
  <plugin id="com.ning.async-http-client" version="1.6.3.201106061504" match="equivalent"/>
  <plugin id="org.jboss.netty" version="3.2.4.Final-201106061504" match="perfect"/>
  <plugin id="org.hamcrest.core" version="1.1.0.v20090501071000" match="equivalent"/>
</requires>

Visualizing OSGi Dependencies

Yesterday I blogged about how to find dependencies in features on plugins or features using a shell script to rip through feature jars.

But maybe you're less commandline, and more visual? Well, it may be over three years old, but there's a way to visualize plugin interdependencies using Ian Bull's PDE Dependency View. Frankly, I'm amazed this isn't already a core feature in PDE (and correct me if it is).

To use this tool, simply install it from:

http://download.eclipse.org/eclipse/pde/incubator/visualization/site

After installing and restarting, hit CTRL-3 and type "Graph" to find the "Graph Plug-In Dependencies View". (It's also available from Window > Show View > Other... (ALT-SHIFT-Q,Q) under Plug-in Development, if you prefer to kick it old-school.)

Next, right-click in the view or hit the "Focus on" button in the view, and select the plugin on which you want to focus.

Now you can browse up or down through plugins to explore dependencies.

For example, to see what plugins depend on a given plugin, such as org.eclipse.tm.terminal, click the "Show Callers" button in the view.

Or, to see on which plugins org.jboss.ide.eclipe.as.rse.ui depends, click the "Show Callees" button in the view. You can shift-click on nodes to highlight them for emphasis, or click and drag them around.

HOWTO: Find osgi dependencies in features

Say you're trying to build something with Tycho & Maven 3 and while resolving dependencies before compilation, you're told:

[INFO] [Software being installed: 
  org.eclipse.tm.terminal.local.feature.group 0.1.0.v201006041240-10-7w312117152433, 
  Missing requirement: 
    org.eclipse.tm.terminal.local 0.1.0.v201006041322 
      requires 
        'bundle org.eclipse.cdt.core 5.2.0' 
          but it could not be found, 
  Cannot satisfy dependency: 
    org.eclipse.tm.terminal.local.feature.group 0.1.0.v201006041240-10-7w312117152433 
      depends on: 
        org.eclipse.tm.terminal.local [0.1.0.v201006041322]]

To quickly verify where this dependency is coming from, you can go look into the feature.xml for the org.eclipse.tm.terminal.local feature jar... but if you don't have it installed, this is somewhat more cumbersome; besides, you then have to unpack the jar before you can look inside it.

And maybe that feature contains a number of OTHER dependencies that you'll also need to resolve in your target platform when building. Sure, there are UI tools to do this within Eclipse, but when you're working on remote servers sometimes UI isn't available.

Workaround? Assuming you have a mirror of the update site(s) from which you're trying to resolve the dependency (eg., Helios) or can ssh to dev.eclipse.org, you can simply run a quick shell script to do the investigative work for you:

$ cd ~/downloads/releases/helios/201009240900/aggregate/; ~/bin/findDepInFeature "*tm*" cdt

./features/org.eclipse.tm.terminal.local_0.1.0.v201006041240-10-7w312117152433.jar
      <import feature="org.eclipse.cdt.platform" version="7.0.0" match="greaterOrEqual"/>
      <import plugin="org.eclipse.cdt.core" version="5.2.0" match="compatible"/>
      <import plugin="org.eclipse.core.runtime"/>

Where the script looks like this:

#!/bin/bash
# find plugins/feature deps by searching in some folder for feature jars, and searching through their feature.xml files for dependencies

# 1 - featurePattern - pattern of features to search (eg., "org.eclipse.tptp" or "\*" for all features)
# 2 - dependencyPattern  - pattern of plugins/feature deps for which to search (eg., "org.eclipse.tptp.platform.instrumentation.ui")
# 3 - location       - directory in which to search, if not "."

if [[ ! $1 ]]; then
        echo "Usage: $0 <featurePattern> <dependencyPattern> <location>"
        echo ""
        echo "Example: $0 tm.terminal cdt"
        exit 1
fi

# if no location, look in current dir (.)
if [[ $3 ]]; then location="$3"; else location="."; fi

# if no featurePattern, search all features for dependencyPattern
if [[ ! $2 ]]; then featurePattern="*"; dependencyPattern="$1"; else dependencyPattern="$2"; featurePattern="$1"; fi

rm -fr /tmp/findinfeature/; mkdir -p /tmp/findinfeature/features/
for f in $(find "$location" -type f -name "*${featurePattern}*" | egrep -v "pack.gz|source" | grep features | egrep "${featurePattern}"); do
        #echo "$f [$featurePattern, $dependencyPattern]"
        unzip -q $f -d /tmp/findinfeature/ feature.xml
        #       <import feature="org.eclipse.cdt.platform" version="7.0.0" match="greaterOrEqual"/>
        #       <import plugin="org.eclipse.cdt.core" version="5.2.0" match="compatible"/>
        if [[ ! $(cat /tmp/findinfeature/feature.xml | egrep "<import" -A3 | egrep "plugin=|feature=" -A1 -B1 | egrep "\".*${dependencyPattern}[^\"]*\"" -A1 -B1) ]]; then
                rm -fr /tmp/findinfeature/feature.xml
        else
                mv /tmp/findinfeature/feature.xml /tmp/findinfeature/${f}_feature.xml
                echo "${f}"
                cat /tmp/findinfeature/${f}_feature.xml | egrep "<import" -A3 | egrep "plugin=|feature=" -A1 -B1 | egrep "\".*${dependencyPattern}[^\"]*\"" -A1 -B1
                echo ""
        fi
        rm -fr /tmp/findinfeature/feature.xml
done

Eclipse Photoshop Challenge: "Better Than MovieOS"

Back in June, we ran a contest to challenge the Eclipse community to photoshop some movie-themed posters to promote Ganymede.

This time, I'd like to propose a different challenge.

• What: An opportunity to show your Photoshoppin' / GIMPin' skillz. Top five community-voted submissions will win Eclipse schwag.
• When: Now through mid-November.
• Why: Because Eclipse is better than MovieOS.
• Who: Anyone with some free time to burn.
• Where: On your blog, or attached to bug 252135.

So, what should you design? The rules are simple. Take a still frame from a movie or TV show, and replace the MovieOS with a screenshot of an Eclipse IDE running your favourite plugins, an RCP or SWT application, or even a mobile OSGi app.

Some links to get you started:

• JavaEE Perspective Screenshots
• Eclipse RCP | Eclipse For You
• Open Source Rich client platform (RCP) applications
• Some screen captures & stills from various movies, TV shows, and applications
• Google Image Search

Some examples: