Issue 1608 - Introduce HG client module in Puppet

modules/hg/manifests/init.pp

+# == Class: hg
+#
+# A very basic Mercurial client integration.
+#
+# === Parameters:
+#
+# Below please find a list of parameters recognized by class hg:
+#
+# [*path*]
+#   A $path to pass on to exec{} when invoking commands. Can be overwritten
+#   in each named type defined by class hg.
+#
+# [*cwd*]
+#   A working directory ($cwd) to pass on to exec{} when invoking commands.
+#   Can be overwritten in each named type defined by class hg.
+#
+# [*package*]
+#   The name of the Mercurial (client) package on the target system.
+#
+# [*post_update*]
+#   An optional shell command to trigger after a successful hg::update(),
+#   using the local repository as working directory.
+#
+# === Examples:
+#
+# Below please find a set of examples demonstrating the use of class hg:
+#
+#   hg {
+#     path        => '/usr/local/bin',
+#     post_update =>
+#       shellquote('test', '-e', 'ensure_dependencies.py') + ' && ' +
+#       shellquote('python', 'ensure_dependencies.py'),
+#   }
+#
+#   hg::ensure {'/opt/sitescripts':
+#     source   => 'https://hg.adblockplus.org/sitescripts',
+#     revision => 'tip',
+#   }

[Wladimir Palant, 2015/01/13 08:10:48]

Does this API make sense for us? We typically don't check out specific
revisions, we rather check out the current state and have it updated
automatically. As you have it implemented right now, the automatic update still
has to be done separately.

[mathias, 2015/06/23 10:45:15]

Well, the revision parameter is optional (and now defaulting to "default"), so
it would behave as expected.

But the keeping-up-to-date thingy is not included here. We can, of course,
include it as an optional (!) feature. I'll have a look into that while
addressing the other feedback from this patch-set.

+#
+class hg(
+  $path        = '/usr/local/bin:/usr/bin:/bin',
+  $cwd         = '/',
+  $package     = 'mercurial',
+  $post_update = '',
+  $user        = 'root') {
+
+  include stdlib
+
+  package {$package:
+    ensure => installed,

[Wladimir Palant, 2015/01/13 08:10:48]

Does a custom path make sense if you require Mercurial to be installed as a
system package?

[mathias, 2015/06/23 10:45:14]

The custom path is also used to ensure the $PATH for the $post_update hook being
modifiable.

+  }
+
+  Exec {
+    path => $path,
+    cwd  => $cwd,
+  }
+
+  define clone(
+    $source,
+    $user   = $user,
+    $target = $name) {
+
+    # Allow for accessing $hg::* class parameters
+    include hg
+
+    $command = shellquote('hg', 'clone', $source, $target)
+
+    exec {$command:
+      creates => $target,
+      user    => $user,
+      require => Package[$hg::package],
+    }
+  }
+
+  define pull(
+    $source = '--',
+    $user   = $user,
+    $target = $name) {
+
+    # Allow for accessing $hg::* class parameters
+    include hg
+
+    $command = shellquote('hg', '--cwd', $target, 'pull', $source)

[Wladimir Palant, 2015/01/13 08:10:48]

Please use -R or --repository rather than --cwd.

+
+    exec {$command:
+      user    => $user,
+      require => Package[$hg::package],
+    }
+  }
+
+  define update(
+    $revision = 'tip',

[Wladimir Palant, 2015/01/13 08:10:48]

'tip' isn't a good default, it might be on a branch. 'default' is what we
usually use (head of the default branch).

+    $user     = $user,
+    $target   = $name) {
+
+    # Allow for accessing $hg::* class parameters
+    include hg
+
+    $command = shellquote('hg', '--cwd', $target, 'pull', '--rev', $revision)

[Wladimir Palant, 2015/01/13 08:10:48]

Please use -R or --repository rather than --cwd.

I guess you want to run hg update here, not hg pull. hg pull won't update unless
--update option is specified.

+
+    exec {$command:
+      user    => $user,
+      require => Package[$hg::package],
+    }
+
+    if $hg::post_update != '' {

[Wladimir Palant, 2015/01/13 08:10:48]

Shouldn't this only be executed when an actual update was performed? Meaning
that |hg id -i| output changed after running the command.

+      exec {"$command #post_update":
+        command => $hg::post_update,
+        user    => $user,
+        cwd     => $target,
+        require => Exec[$command],
+      }
+    }
+  }
+
+  define ensure(
+    $source,
+    $revision = 'tip',
+    $user     = $user,
+    $target   = $name) {
+
+    hg::clone {$name:
+      source => $source,
+      user   => $user,
+      target => $target,
+    }

[Wladimir Palant, 2015/01/13 08:10:48]

Should this really be run unconditionally? What if the target directory already
exists?

+
+    -> # after clone
+    hg::pull {$name:
+      source => $source,
+      user   => $user,
+      target => $target,
+    }
+
+    -> # after pull
+    hg::update {$name:
+      revision => $revision,
+      user     => $user,
+      target   => $target,
+    }
+  }
+}