Split up RequiredCommands task.

The requirements are now located in the appropriate modules

common/task_sets.py

@@ -12,7 +12,7 @@ from common.tasks import security
 from common.tasks import locale
 
 base_set = [workspace.CreateWorkspace,
-            host.AddExternalCommands,
+            bootstrap.AddRequiredCommands,
             host.CheckExternalCommands,
             bootstrap.Bootstrap,
             workspace.DeleteWorkspace,
@@ -20,11 +20,13 @@ base_set = [workspace.CreateWorkspace,
 
 volume_set = [volume.Attach,
               volume.Detach,
+              filesystem.AddRequiredCommands,
               filesystem.Format,
               filesystem.FStab,
               ]
 
-partitioning_set = [partitioning.PartitionVolume,
+partitioning_set = [partitioning.AddRequiredCommands,
+                    partitioning.PartitionVolume,
                     partitioning.MapPartitions,
                     partitioning.UnmapPartitions,
                     ]

common/tasks/bootstrap.py

@@ -1,10 +1,21 @@
 from base import Task
 from common import phases
 from common.exceptions import TaskError
+import host
 import logging
 log = logging.getLogger(__name__)
 
 
+class AddRequiredCommands(Task):
+	description = 'Adding commands required bootstrapping Debian'
+	phase = phases.preparation
+	successors = [host.CheckExternalCommands]
+
+	@classmethod
+	def run(cls, info):
+		info.host_dependencies['debootstrap'] = 'debootstrap'
+
+
 def get_bootstrap_args(info):
 	executable = ['/usr/sbin/debootstrap']
 	options = ['--arch=' + info.manifest.system['architecture']]

common/tasks/filesystem.py

@@ -2,10 +2,22 @@ from base import Task
 from common import phases
 from common.tools import log_check_call
 from bootstrap import Bootstrap
-from common.tasks import apt
+import apt
+import host
 import volume
 
 
+class AddRequiredCommands(Task):
+	description = 'Adding commands required for formatting the partitions'
+	phase = phases.preparation
+	successors = [host.CheckExternalCommands]
+
+	@classmethod
+	def run(cls, info):
+		if 'xfs' in (p.filesystem for p in info.volume.partition_map.partitions):
+			info.host_dependencies['mkfs.xfs'] = 'xfsprogs'
+
+
 class Format(Task):
 	description = 'Formatting the volume'
 	phase = phases.volume_preparation

common/tasks/host.py

@@ -3,35 +3,9 @@ from common import phases
 from common.exceptions import TaskError
 
 
-class AddExternalCommands(Task):
-	description = 'Determining which external commands are required'
-	phase = phases.preparation
-
-	@classmethod
-	def run(cls, info):
-		info.host_dependencies['debootstrap'] = 'debootstrap'
-
-		from common.fs.loopbackvolume import LoopbackVolume
-		if isinstance(info.volume, LoopbackVolume):
-			info.host_dependencies['qemu-img'] = 'qemu-utils'
-			info.host_dependencies['losetup'] = 'mount'
-		from common.fs.qemuvolume import QEMUVolume
-		if isinstance(info.volume, QEMUVolume):
-			info.host_dependencies['losetup'] = 'qemu-nbd'
-
-		if 'xfs' in (p.filesystem for p in info.volume.partition_map.partitions):
-			info.host_dependencies['mkfs.xfs'] = 'xfsprogs'
-
-		from base.fs.partitionmaps.none import NoPartitions
-		if not isinstance(info.volume.partition_map, NoPartitions):
-			info.host_dependencies['parted'] = 'parted'
-			info.host_dependencies['kpartx'] = 'kpartx'
-
-
 class CheckExternalCommands(Task):
 	description = 'Checking availability of external commands'
 	phase = phases.preparation
-	predecessors = [AddExternalCommands]
 
 	@classmethod
 	def run(cls, info):

common/tasks/loopback.py

@@ -1,8 +1,25 @@
 from base import Task
 from common import phases
+import host
 import volume
 
 
+class AddRequiredCommands(Task):
+	description = 'Adding commands required for creating loopback volumes'
+	phase = phases.preparation
+	successors = [host.CheckExternalCommands]
+
+	@classmethod
+	def run(cls, info):
+		from common.fs.loopbackvolume import LoopbackVolume
+		if isinstance(info.volume, LoopbackVolume):
+			info.host_dependencies['qemu-img'] = 'qemu-utils'
+			info.host_dependencies['losetup'] = 'mount'
+		from common.fs.qemuvolume import QEMUVolume
+		if isinstance(info.volume, QEMUVolume):
+			info.host_dependencies['losetup'] = 'qemu-nbd'
+
+
 class Create(Task):
 	description = 'Creating a loopback volume'
 	phase = phases.volume_creation

common/tasks/partitioning.py

@@ -1,9 +1,23 @@
 from base import Task
 from common import phases
 import filesystem
+import host
 import volume
 
 
+class AddRequiredCommands(Task):
+	description = 'Adding commands required for partitioning the volume'
+	phase = phases.preparation
+	successors = [host.CheckExternalCommands]
+
+	@classmethod
+	def run(cls, info):
+		from base.fs.partitionmaps.none import NoPartitions
+		if not isinstance(info.volume.partition_map, NoPartitions):
+			info.host_dependencies['parted'] = 'parted'
+			info.host_dependencies['kpartx'] = 'kpartx'
+
+
 class PartitionVolume(Task):
 	description = 'Partitioning the volume'
 	phase = phases.volume_preparation

providers/ec2/__init__.py

@@ -97,7 +97,8 @@ def resolve_tasks(taskset, manifest):
 	                                  tasks.ebs.Attach,
 	                                  filesystem.FStab,
 	                                  tasks.ebs.Snapshot],
-	                          's3': [loopback.Create,
+	                          's3': [loopback.AddRequiredCommands,
+	                                 loopback.Create,
 	                                 volume.Attach,
 	                                 tasks.filesystem.S3FStab,
 	                                 tasks.ami.BundleImage,