Use global state to check for duplicate fs labels

As we add file-systems, add them to global state and check the labels
are uniqiue.  Add a unit test and remove the old global value.

Bonus fixup to the length check, and a test for that too.

Change-Id: I0f5a96f687c92e000afc9c98a26c49c4b1d3f28d

diskimage_builder/block_device/level2/mkfs.py

@@ -25,10 +25,6 @@ from diskimage_builder.block_device.utils import exec_sudo
 logger = logging.getLogger(__name__)
 
 
-# There is the need that filesystem labels are unique:
-# if not the boot and / or mount (with LABEL=) might fail.
-file_system_labels = set()
-
 # There is the need to check the length of the label of
 # the filesystem.  The maximum length depends on the used filesystem.
 # This map provides information about the maximum label length.
@@ -69,20 +65,25 @@ class FilesystemNode(NodeBase):
                            "file system - using [img-rootfs] instead")
             self.label = "img-rootfs"
 
-        if self.label in file_system_labels:
-            raise BlockDeviceSetupException(
-                "File system label [%s] used more than once" % self.label)
-        file_system_labels.add(self.label)
+        # ensure we don't already have a fs with this label ... they
+        # all must be unique.
+        if 'fs_labels' in self.state:
+            if self.label in self.state['fs_labels']:
+                raise BlockDeviceSetupException(
+                    "File system label [%s] used more than once" % self.label)
+            self.state['fs_labels'].append(self.label)
+        else:
+            self.state['fs_labels'] = [self.label]
 
         if self.type in file_system_max_label_length:
             if file_system_max_label_length[self.type] < len(self.label):
                 raise BlockDeviceSetupException(
                     "Label [{label}] too long for filesystem [{type}]: "
-                    " [{len}] > [{max_len}]".format({
+                    "{len} > {max_len}".format(**{
                         'label': self.label,
                         'type': self.type,
                         'len': len(self.label),
-                        'max': file_system_max_label_length[self.type]}))
+                        'max_len': file_system_max_label_length[self.type]}))
         else:
             logger.warning("Length of label [%s] cannot be checked for "
                            "filesystem [%s]: unknown max length",

diskimage_builder/block_device/tests/config/duplicate_fs_labels.yaml

@@ -0,0 +1,68 @@
+- local_loop:
+    name: image0
+
+- partitioning:
+      base: image0
+      name: mbr
+      label: mbr
+      partitions:
+        - name: root
+          base: image0
+          flags: [ boot, primary ]
+          size: 55%
+        - name: var
+          base: image0
+          size: 40%
+        - name: var_log
+          base: image0
+          size: 5%
+
+- mkfs:
+    base: root
+    name: mkfs_root
+    label: duplicate
+    type: xfs
+
+- mount:
+    base: mkfs_root
+    name: mount_mkfs_root
+    mount_point: /
+
+- fstab:
+    base: mount_mkfs_root
+    name: fstab_mount_mkfs_root
+    fsck-passno: 1
+    options: defaults
+
+- mkfs:
+    base: var
+    name: mkfs_var
+    label: duplicate
+    type: xfs
+
+- mount:
+    base: mkfs_var
+    name: mount_mkfs_var
+    mount_point: /var
+
+- fstab:
+    base: mount_mkfs_var
+    name: fstab_mount_mkfs_var
+    fsck-passno: 1
+    options: defaults
+
+- mkfs:
+    base: var_log
+    name: mkfs_var_log
+    type: xfs
+
+- mount:
+    base: mkfs_var_log
+    name: mount_mkfs_var_log
+    mount_point: /var/log
+
+- fstab:
+    base: mount_mkfs_var_log
+    name: fstab_mount_mkfs_var_log
+    fsck-passno: 1
+    options: defaults

diskimage_builder/block_device/tests/config/too_long_fs_label.yaml

@@ -0,0 +1,5 @@
+- mkfs:
+    base: fake
+    name: mkfs_root
+    label: this_label_is_too_long_to_work_with_xfs
+    type: xfs

diskimage_builder/block_device/tests/test_config.py

@@ -29,8 +29,6 @@ class TestConfig(TestBase):
 
         # reset all globals for each test.
         # XXX: remove globals :/
-        import diskimage_builder.block_device.level2.mkfs
-        diskimage_builder.block_device.level2.mkfs.file_system_labels = set()
         import diskimage_builder.block_device.level3.mount
         diskimage_builder.block_device.level3.mount.sorted_mount_points = []
 

diskimage_builder/block_device/tests/test_mkfs.py

@@ -0,0 +1,43 @@
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+
+import logging
+
+import diskimage_builder.block_device.tests.test_config as tc
+
+from diskimage_builder.block_device.config import create_graph
+from diskimage_builder.block_device.exception import \
+    BlockDeviceSetupException
+
+
+logger = logging.getLogger(__name__)
+
+
+class TestMkfs(tc.TestGraphGeneration):
+
+    def test_duplicate_labels(self):
+
+        config = self.load_config_file('duplicate_fs_labels.yaml')
+
+        self.assertRaisesRegex(BlockDeviceSetupException,
+                               "used more than once",
+                               create_graph, config,
+                               self.fake_default_config, {})
+
+    def test_too_long_labels(self):
+
+        config = self.load_config_file('too_long_fs_label.yaml')
+
+        self.assertRaisesRegex(BlockDeviceSetupException,
+                               "too long for filesystem",
+                               create_graph, config,
+                               self.fake_default_config, {})