vim scripting: replacing timestamps

After weeks of manually updating compositeArtifacts.xml and compositeContent.xml files' timestamps using `date +%s000`, I finally snapped and went looking for a better way.

Using the Vim Tips wiki as inspiration, I cobbled together this keymapped string replacement function for use in Vim:

" add this to your ~/.vimrc file, then type '\ts' to update timestamp to current
fun! ReplaceTimestamp()
   let tstamp = strftime("%s000")
   exe ":%s#<property name='p2.timestamp' value='[0-9]\\+'/>#<property name='p2.timestamp' value='" . tstamp . "'/>#g"
   echo "New time: " . tstamp
endfun
nnoremap <Leader>ts :call ReplaceTimestamp()<CR>

Syntax highlighting for code snippets in blogs

Where does he get those wonderful toys? - The Joker, Batman (1989)

Recently I was asked how I make code snippets on this blog prettier. Here's how.

1. In your blog's template, install Alex Gorbatchev's Syntax Highlighter.
2. Then, in the body of the blog post (with all occurrences of "<" HTML-escaped as "&lt"):

   <pre class="brush:shell"> ... </pre>
   or
   <pre class="brush:java"> ... </pre>
   or
   <pre class="brush:xml"> ... </pre>

3. There are other "brushes" available too with which you can "paint" your code. I generally only need java, xml, and shell.

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

HOWTO: Find the feature that contains a plugin

Tycho is awesome.

However, like all build systems, it has its limitations.

One such limitation is that when you're building against a target platform, and something's missing, you get errors such as these:

[INFO] Cannot complete the request.  Generating details.
{org.osgi.framework.executionenvironment=OSGi/Minimum-1.0,OSGi/Minimum-1.1, osgi.ws=cocoa, osgi.arch=x86, osgi.os=macosx, org.eclipse.update.install.features=true, org.osgi.framework.system.packages=}
[Software being installed: org.jboss.tools.tptp.feature.feature.group 1.2.0.qualifier, Missing requirement: org.eclipse.tptp.platform.instrumentation.ui 4.4.1.v201009092123 requires 'bundle org.eclipse.hyades.probekit [4.2.0,5.0.0)' but it could not be found, Cannot satisfy dependency: org.eclipse.tptp.platform.instrumentation.ui.feature.group 4.3.1.v201009092123-797908s73533D4H6D56 depends on: org.eclipse.tptp.platform.instrumentation.ui [4.4.1.v201009092123], Cannot satisfy dependency: org.jboss.tools.tptp.feature.feature.group 1.2.0.qualifier depends on: org.eclipse.tptp.platform.instrumentation.ui.feature.group 4.3.0]
[ERROR] Internal error: java.lang.RuntimeException: org.eclipse.equinox.p2.core.ProvisionException: No solution found because the problem is unsatisfiable. -> [Help 1]
org.apache.maven.InternalErrorException: Internal error: java.lang.RuntimeException: org.eclipse.equinox.p2.core.ProvisionException: No solution found because the problem is unsatisfiable.

The important part of that error message is as follows:

org.jboss.tools.tptp.feature.feature.group 1.2.0.qualifier
   requirement: org.eclipse.tptp.platform.instrumentation.ui 4.4.1.v201009092123 
      requires 'bundle org.eclipse.hyades.probekit [4.2.0,5.0.0)' 
         but it could not be found

org.eclipse.tptp.platform.instrumentation.ui.feature.group 4.3.1.v201009092123-797908s73533D4H6D56 
   depends on: org.eclipse.tptp.platform.instrumentation.ui [4.4.1.v201009092123]
     dependency: org.jboss.tools.tptp.feature.feature.group 1.2.0.qualifier 
        depends on: org.eclipse.tptp.platform.instrumentation.ui.feature.group 4.3.0]

So, how do you find which feature contains that plugin, so that you can add it to your target platform?

First, you need access to the repository. If you have direct server access to the repository from which the plugin comes (eg., the TPTP Helios update site), you can run this script in the root of that repository.

If you don't have server access (eg., you can't ssh to dev.eclipse.org and look in ~/downloads/tptp/updates/helios), then you can pull down a zip of the site (or use a p2.mirror script to fetch a copy of the site to your local machine)... and then run this script in the root of that repository.

Essentially the script finds matching feature jar files, unpacks them to extract the feature.xml files therein, and then greps those files for lines which suggest an included plugin matching the pattern for which you're searching:

$ findInFeature platform.probekit
./features/org.eclipse.tptp.platform.probekit_4.5.1.v201009092123-7H7BF8PAkF7B77ZARCNEK.jar
   <plugin
         id="org.eclipse.tptp.platform.probekit"

./features/org.eclipse.tptp.platform.trace_4.5.1.v201009092123-7L7O8bBgJ9E99jAfGWEM.jar
   <plugin
         id="org.eclipse.tptp.platform.probekit.launch"

From there, it's a trivial exercise to add another line item into your target platform file. First, paste in the feature jar:

./features/org.eclipse.tptp.platform.probekit_4.5.1.v201009092123-7H7BF8PAkF7B77ZARCNEK.jar

Then use vim to pattern-replace that string:

:%s/.\+\/\(org.\+\)_\(\d\+.\+\)\.jar/\t\t\t/g

And you'll end up with a new .feature.group added to the target:

<unit version="4.5.1.v201009092123-7H7BF8PAkF7B77ZARCNEK" id="org.eclipse.tptp.platform.probekit.feature.group"/>

HOWTO: timestamp your Bash prompt

This has always been a pain for me -- waiting for crontab events to kick, you have to keep typing date or date;ls -la|tail waiting for files to show up.

Recently, I got annoyed enough to take matters into my own hands, and I found this. Most of the advice in there doesn't seem to work for the system I was working on, but I worked out another solution, using the PROMPT_COMMAND variable. The following code should go in your ~/.bashrc, /etc/bashrc, or equivalent.

red="\033[1;31m";
norm="\033[0;39m";
cyan="\033[1;36m";
if [ "$PS1" ]; then
    if [[ $UID -eq 0 ]]; then
      PS1="\[$red\]\u@\h:\w\\[\033[0;39m\]\n# "
    else
      PS1="\[$cyan\]\u@\h:\w\\[\033[0;39m\]\n\$ "
    fi
    export PROMPT_COMMAND="echo -n \[\$(date +%H:%M:%S)\]"
    export PS1=" "$PS1"\[\e]30;\u@\h\a\]"
fi

The result?

[15:17:16] nickb@emft:/opt
$ 

- or, when logged in as root -

[15:18:06] root@emft:/home/nickb
#