BashTemplate - problem resolving relative symlinks on the bash file (not the directory)

[muuki88]

Hi,

play-2.2 integrates now the sbt-native-packager plugin. However the [https://github.com/sbt/sbt-native-packager/blob/master/src/main/resources/com/typesafe/sbt/packager/archetypes/bash-template](start script) in a debian package doesn't work, when it's not called within in /usr/share/<appname>/bin folder.

The problem with the bash script seems to be that realpath() cannot handle the relative symlink correctly.

/usr/bin/<appname> -> ../share/<appname>/bin/<appname>

h4. steps to reproduce

play new play-script-test
cd play-script-test

Follow ingbuild.sbt

import com.typesafe.sbt.packager.Keys._

name := "play-script-test"

version := "1.0"

libraryDependencies ++= Seq(
  jdbc,
  anorm,
  cache
)     

play.Project.playScalaSettings

maintainer in Debian := "John Doe <[email protected]>"

packageSummary in Linux := "My custom package summary"

packageDescription := "My longer package description"

Than run

play clean dist debian:packageBin
sudo dpkg -i target/play-script-test-1.0.deb
# open new console
play-script-test

when I run ./<app> from /usr/share/<app>/bin everything works. On every other path it fails, as it cannot find the /usr/share/<app>/lib aka the lib_dir.

[muuki88]

I found the setting where it's done, which is rather uncool.

https://github.com/sbt/sbt-native-packager/blob/master/src/main/scala/com/typesafe/sbt/packager/debian/DebianPlugin.scala#L115

The setting should be absolute by default as relative symlink resolution is rather complicated.

[jsuereth]

The reason it's relative is actually because I had issues getting the debian file to generate correctly with absolute symlinks. I'm more than happy to take a patch on this. I'm looking into it now.

[muuki88]

Nice. Maybe the symbolic-link logic should be done with: JavaNIO http://docs.oracle.com/javase/tutorial/essential/io/links.html

[jsuereth]

I'd love to, except (unfortunately) we're still supporting JDK6. Literally HALF off this code would disappaer/be easier with JDK7, but we're stuck for now.

[muuki88]

# walking up from /usr/share/your-app/bin/your-app to /usr/share/your-app
declare -r app_home=$(dirname $(dirname $(readlink -f $0)))
# TODO - Check whether this is ok in cygwin...
declare -r lib_dir=$app_home/lib

not really nice, but it works. However this isn't tested with cygwin.

[jsuereth]

Ok, I have a bit more robust fix that retains the current mechanism (which we should try to retain the current realpath, as it fixes a few issues that cropped up on odd systems).

Thanks for the patch idea though. Helped me isolate the underlying problem.