method to check for package installation

[Graham Allan]

I'm trying to write a method file to check if a particular RPM package
is installed, and if not, install it.

So far I've completely failed to make cfengine check whether a package
is installed, when the package name is held in a variable.

Attempts 1 and 2 were to define a class.

classes:
  package_installed = ( '/bin/rpm -q ${packagename}' )

and...

classes:
  package_installed = ( ReturnsZero(/bin/rpm -q ${packagename}) )

Attempt 3 was use use the "packages" action.

packages:
  any::
        $(packagename) pkgmgr=rpm define=package_installed


In every case, the cfengine output shows that rpm is being called to
check for a literal "${packagename}" package - the variable is not
getting substituted. The same commands work fine when they contain the
literal package name.

Is there any way I've missed that might make this work?

G.
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Graham Allan
School of Physics and Astronomy - University of Minnesota
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