Add per volume support for brick chaining.

* Don't use this feature unless you _really_ know what you're doing.
* Managing chained volumes is much harder than managing normal ones.
* If some of the volumes in the cluster use this, and others don't, then
you'll probably have an even crazier time with management.
* Please verify my algorithm and feel free to suggest changes.
* Some edge cases haven't been tested.
* This patch breaks out brick layout ordering into individual functions.

4 files changed, 255 insertions, 1 deletions

diff --git a/lib/puppet/parser/functions/brick_layout_chained.rb b/lib/puppet/parser/functions/brick_layout_chained.rb
new file mode 100644
index 0000000..072fba9
--- /dev/null
+++ b/lib/puppet/parser/functions/brick_layout_chained.rb
@@ -0,0 +1,137 @@
+# GlusterFS module by James
+# Copyright (C) 2010-2013+ James Shubin
+# Written by James Shubin <james@shubin.ca>
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+module Puppet::Parser::Functions
+	newfunction(:brick_layout_chained, :type => :rvalue, :doc => <<-'ENDHEREDOC') do |args|
+		Return the complex chained brick list
+
+		Example:
+
+			$layout = brick_layout_chained($replica, $bricks)
+			notice("layout is: ${layout}")
+
+		This function is used internally for automatic brick layouts.
+
+		ENDHEREDOC
+
+		# signature: node, zone -> ip
+		unless args.length == 2
+			raise Puppet::ParseError, "brick_layout_chained(): wrong number of arguments (#{args.length}; must be 2)"
+		end
+		if not(args[0].is_a?(Integer)) and not(args[0].is_a?(String))
+			# NOTE: strings that convert to int's with .to_i are ok
+			raise Puppet::ParseError, "brick_layout_chained(): expects the first argument to be an integer, got #{args[0].inspect} which is of type #{args[0].class}"
+		end
+		unless args[1].is_a?(Array)
+			raise Puppet::ParseError, "brick_layout_chained(): expects the first argument to be an array, got #{args[1].inspect} which is of type #{args[1].class}"
+		end
+
+		replica = args[0].to_i	# convert from string if needed
+		bricks = args[1]
+
+		# TODO: these functions could be in separate puppet files
+		# eg: Puppet::Parser::Functions.function('myfunc')
+		# function_myfunc(...)
+		def brick_str_to_hash(bricks)
+			# this loop converts brick strings to brick dict's...
+			result = []
+			bricks.each do |x|
+				a = x.split(':')
+				#assert a.length == 2	# TODO
+				p = a[1]
+				p = ((p[-1, 1] == '/') ? p : (p+'/'))	# endswith
+
+				result.push({'host'=> a[0], 'path'=> p})
+			end
+			return result
+		end
+
+		def get_hostlist(bricks)
+			hosts = []
+			bricks.each do |x|
+				key = x['host']
+				val = x['path']
+
+				if not hosts.include?(key)
+					hosts.push(key)
+				end
+			end
+			return hosts
+		end
+
+		def get_brickstacks(bricks, sort=false)
+			stacks = {}
+			hosts = get_hostlist(bricks)
+			bricks.each do |x|
+				key = x['host']
+				val = x['path']
+				if not stacks.include?(key); stacks[key] = []; end	# initialize
+				stacks[key].push(val)
+			end
+
+			# optionally sort the paths in each individual host stack...
+			if sort
+				sorted_stacks = {}
+				stacks.each do |k, v|
+					# TODO: there should probably be a proper 'sorted' function for
+					# paths, in case they aren't numbered sanely _WITH_ padding.
+					sorted_stacks[k] = v.sort
+				end
+				return sorted_stacks
+			end
+			return stacks
+		end
+
+		final = []
+		pointer = 0
+		parsed = brick_str_to_hash(bricks)
+		# TODO: there should probably be a proper 'sorted' function for
+		# hostnames, in case they aren't numbered sanely _WITH_ padding.
+		hosts = get_hostlist(bricks).sort
+		brickstack = get_brickstacks(bricks, sort=true)
+
+		if bricks.length == 0; return []; end
+
+		# FIXME: this works with homogeneous volumes only!
+		while pointer < (hosts.length * brickstack[hosts[0]].length) do
+			start = hosts[pointer % hosts.length]
+			#puts "host is #{host}, pointer is: #{pointer}"
+
+			index = 0
+			while index < replica do
+				host = hosts[(pointer+index) % hosts.length]
+				#puts "host is #{host}, index is: #{index}"
+				index+= 1
+
+				path = brickstack[host].shift	# yoink
+				if path.nil?
+					# TODO: is raise okay?
+					raise Puppet::ParseError, "brick_layout_chained(): brick list is not valid"
+					next
+				end
+				final.append({'host' => host, 'path' => path})	# save
+			end
+			pointer+=1
+		end
+
+		# build final result
+		result = final.collect {|x| x['host']+':'+x['path'] }
+		result	# return
+	end
+end
+
+# vim: ts=8
diff --git a/lib/puppet/parser/functions/brick_layout_simple.rb b/lib/puppet/parser/functions/brick_layout_simple.rb
new file mode 100644
index 0000000..7b3a6eb
--- /dev/null
+++ b/lib/puppet/parser/functions/brick_layout_simple.rb
@@ -0,0 +1,105 @@
+# GlusterFS module by James
+# Copyright (C) 2010-2013+ James Shubin
+# Written by James Shubin <james@shubin.ca>
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+module Puppet::Parser::Functions
+	newfunction(:brick_layout_simple, :type => :rvalue, :doc => <<-'ENDHEREDOC') do |args|
+		Return the simple symmetrical brick list
+
+		Example:
+
+			$layout = brick_layout_simple($replica, $bricks)
+			notice("layout is: ${layout}")
+
+		This function is used internally for automatic brick layouts.
+
+		ENDHEREDOC
+
+		# signature: node, zone -> ip
+		unless args.length == 2
+			raise Puppet::ParseError, "brick_layout_simple(): wrong number of arguments (#{args.length}; must be 2)"
+		end
+		if not(args[0].is_a?(Integer)) and not(args[0].is_a?(String))
+			# NOTE: strings that convert to int's with .to_i are ok
+			raise Puppet::ParseError, "brick_layout_simple(): expects the first argument to be an integer, got #{args[0].inspect} which is of type #{args[0].class}"
+		end
+		unless args[1].is_a?(Array)
+			raise Puppet::ParseError, "brick_layout_simple(): expects the first argument to be an array, got #{args[1].inspect} which is of type #{args[1].class}"
+		end
+
+		replica = args[0].to_i	# convert from string if needed
+		bricks = args[1]
+
+		# TODO: these functions could be in separate puppet files
+		# eg: Puppet::Parser::Functions.function('myfunc')
+		# function_myfunc(...)
+		def brick_str_to_hash(bricks)
+			# this loop converts brick strings to brick dict's...
+			result = []
+			bricks.each do |x|
+				a = x.split(':')
+				#assert a.length == 2	# TODO
+				p = a[1]
+				p = ((p[-1, 1] == '/') ? p : (p+'/'))	# endswith
+
+				result.push({'host'=> a[0], 'path'=> p})
+			end
+			return result
+		end
+
+		collect = {}
+		parsed = brick_str_to_hash(bricks)
+		parsed.each do |x|
+			key = x['host']
+			val = x['path']
+
+			if not collect.has_key?(key)
+				collect[key] = []	# initialize
+			end
+
+			collect[key].push(val)	# save in array
+			# TODO: ensure this array is always sorted (we could also do this after
+			# or always insert elements in the correct sorted order too :P)
+			collect[key] = collect[key].sort
+		end
+
+		# we also could do this sort here...
+		collect.keys.each do |x|
+			collect[x] = collect[x].sort
+		end
+
+		final = []	# final order...
+		# TODO: here we can probably detect if this is an asymmetrical configurations, or maybe bad naming...
+		while collect.size > 0
+			collect.keys.sort.each do |x|
+
+				# NOTE: this array should already be sorted!
+				p = collect[x].shift	# assume an array of at least 1 element
+				final.push( { 'host' => x, 'path' => p } )	# save
+
+				if collect[x].size == 0		# maybe the array is empty now
+					collect.delete(x)	# remove that empty list's key
+				end
+			end
+		end
+
+		# build final result
+		result = final.collect {|x| x['host']+':'+x['path'] }
+		result	# return
+	end
+end
+
+# vim: ts=8
diff --git a/manifests/simple.pp b/manifests/simple.pp
index fc4da96..dbd43ed 100644
--- a/manifests/simple.pp
+++ b/manifests/simple.pp
@@ -20,6 +20,7 @@ class gluster::simple(
 	$volume = 'puppet',	# NOTE: this can be a list...
 	$replica = 1,
 	$stripe = 1,		# TODO: not fully implemented in puppet-gluster
+	$layout = '',		# brick layout to use (default, chained, etc...)
 	$vip = '',		# strongly recommended
 	$vrrp = false,
 	$password = '',	# global vrrp password to use
@@ -158,6 +159,7 @@ class gluster::simple(
 	gluster::volume { $valid_volumes:
 		replica => $replica,
 		stripe => $stripe,
+		layout => "${layout}",
 		# NOTE: with this method you do not choose the order of course!
 		# the gluster_fqdns fact is alphabetical, but not complete till
 		# at least a puppet run of each node has occured. watch out for
diff --git a/manifests/volume.pp b/manifests/volume.pp
index 645c090..c6e285d 100644
--- a/manifests/volume.pp
+++ b/manifests/volume.pp
@@ -21,6 +21,9 @@ define gluster::volume(
 	$transport = 'tcp',
 	$replica = 1,
 	$stripe = 1,
+	# TODO: maybe this should be called 'chained' => true/false, and maybe,
+	# we can also specify an offset count for chaining, or other parameters
+	$layout = '',		# brick layout to use (default, chained, etc...)
 	$vip = '',		# vip of the cluster (optional but recommended)
 	$ping = true,		# do we want to include fping checks ?
 	$settle = true,		# do we want to run settle checks ?
@@ -76,9 +79,15 @@ define gluster::volume(
 
 	$gluster_brick_group_fact = getvar("gluster_brick_group_${group}")
 	$collected_bricks = split($gluster_brick_group_fact, ',')
+	# run the appropriate layout function here
+	$ordered_brick_layout = $layout ? {
+		'chained' => brick_layout_chained($replica, $collected_bricks),
+		default => brick_layout_simple($replica, $collected_bricks),
+	}
+
 	$valid_bricks = type($bricks) ? {
 		'boolean' => $bricks ? {
-			true => $collected_bricks,		# an array...
+			true => $ordered_brick_layout,		# an array...
 			default => [],				# invalid type
 		},
 		'list' => $bricks,
@@ -86,6 +95,7 @@ define gluster::volume(
 	}
 
 	# helpful debugging!
+	notice(inline_template('collected_bricks: <%= @collected_bricks.inspect %>'))
 	notice(inline_template('valid_bricks: <%= @valid_bricks.inspect %>'))
 
 	# NOTE: we're using the valid_bricks value here, and not the collected