Adding package versioning logic to package_command

This change adds the ability to provide specific package versions to
Distro.install_packages and subsequently Distro.package_command. In order
to effectively use Distro.install_packages, one is now able to pass a
variety of formats in order to easily manage package requirements. These
are examples of what can be passed:
- "package"
- ["package1","package2"]
- ("package",)
- ("package", "version")
- [("package1",)("package2",)]
- [("package1", "version1"),("package2","version2")]

This change also adds the option to install a specific version for the
puppet configuration module.  This is especially important here as
successful puppet deployments are highly reliant on specific puppet
versions.

1 files changed, 23 insertions, 0 deletions

diff --git a/cloudinit/util.py b/cloudinit/util.py
index c0ea8d91..c9c5f794 100644
--- a/cloudinit/util.py
+++ b/cloudinit/util.py
@@ -1560,3 +1560,26 @@ def is_partition(device):
         device = device[5:]
 
     return os.path.isfile("/sys/class/block/%s/partition" % device)
+
+
+def expand_package_list(version_fmt, pkgs):
+    # we will accept tuples, lists of tuples, or just plain lists
+    if not isinstance(pkgs, list):
+        pkgs = [pkgs]
+
+    pkglist = []
+    for pkg in pkgs:
+        if isinstance(pkg, str):
+            pkglist.append(pkg)
+            continue
+
+        if len(pkg) < 1 or len(pkg) > 2:
+            raise RuntimeError("Invalid package_command tuple.")
+
+        if len(pkg) == 2 and pkg[1]:
+            pkglist.append(version_fmt % pkg)
+            continue
+
+        pkglist.append(pkg[0])
+
+    return pkglist