Support setting hostname

We get a name value in the config drive meta_data.json, lets use this
for setting a hostname. Also write out a hosts entry for 127.0.1.1 to
hostname.

Change-Id: Ia9155bc565ad79af44d88acc06759be2bf4e5f20

glean/cmd.py

@@ -18,6 +18,7 @@ import argparse
 import json
 import os
 import platform
+import re
 import subprocess
 import sys
 import time
@@ -325,6 +326,42 @@ def write_ssh_keys(args):
     finish_files(files_to_write, args)
 
 
+def set_hostname_from_config_drive(args):
+    if args.noop:
+        return
+
+    config_drive = os.path.join(args.root, 'mnt/config')
+    meta_data_path = '%s/openstack/latest/meta_data.json' % config_drive
+    if not os.path.exists(meta_data_path):
+        return
+
+    meta_data = json.load(open(meta_data_path))
+    if 'name' not in meta_data:
+        return
+
+    hostname = meta_data['name']
+
+    ret = subprocess.call(['hostname', hostname])
+
+    if ret != 0:
+        raise RuntimeError('Error setting hostname')
+    else:
+        with open('/etc/hostname', 'w') as fh:
+            fh.write(hostname)
+            fh.write('\n')
+
+        # See if we already have a hosts entry for hostname
+        prog = re.compile('^127.0.1.1 .*%s' % hostname)
+        match = None
+        with open('/etc/hosts') as fh:
+            match = prog.match(fh.read())
+
+        # Write out a hosts entry for hostname
+        if match is None:
+            with open('/etc/hosts', 'w+') as fh:
+                fh.write('127.0.1.1 %s\n' % hostname)
+
+
 def main():
     parser = argparse.ArgumentParser(description="Static network config")
     parser.add_argument(
@@ -340,12 +377,17 @@ def main():
         default=None, help="Interface to process")
     parser.add_argument(
         '--ssh', dest='ssh', action='store_true', help="Write ssh key")
+    parser.add_argument(
+        '--hostname', dest='hostname', action='store_true',
+        help="Set the hostname if name is available in config drive.")
     parser.add_argument(
         '--skip-network', dest='skip', action='store_true',
         help="Do not write network info")
     args = parser.parse_args()
     if args.ssh:
         write_ssh_keys(args)
+    if args.hostname:
+        set_hostname_from_config_drive(args)
     if args.interface != 'lo' and not args.skip:
         write_network_info_from_config_drive(args)
     return 0

glean/tests/test_glean.py

@@ -13,6 +13,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import json
 import os
 
 import fixtures
@@ -54,13 +55,15 @@ class TestGlean(base.BaseTestCase):
         def open_side_effect(*args, **kwargs):
             if (args[0].startswith('/etc/network') or
                     args[0].startswith('/etc/sysconfig/network-scripts') or
-                    args[0].startswith('/etc/resolv.conf')):
+                    args[0].startswith('/etc/resolv.conf') or
+                    args[0] in ('/etc/hostname', '/etc/hosts')):
                 try:
                     mock_handle = self.file_handle_mocks[args[0]]
                 except KeyError:
                     mock_handle = mock.Mock()
                     mock_handle.__enter__ = mock.Mock(return_value=mock_handle)
                     mock_handle.__exit__ = mock.Mock()
+                    mock_handle.read.return_value = ''
                     self.file_handle_mocks[args[0]] = mock_handle
                 return mock_handle
             elif args[0].startswith('/sys/class/net'):
@@ -113,11 +116,15 @@ class TestGlean(base.BaseTestCase):
 
         self.useFixture(fixtures.MonkeyPatch('platform.dist', fake_distro))
 
-    def _assert_network_output(self, distro, provider):
-        self._patch_argv([])
+    def _assert_distro_provider(self, distro, provider):
+        self._patch_argv(['--hostname'])
         self._patch_files(provider)
         self._patch_distro(distro)
 
+        mock_call = mock.Mock()
+        mock_call.return_value = 0
+        self.useFixture(fixtures.MonkeyPatch('subprocess.call', mock_call))
+
         cmd.main()
 
         output_filename = '%s.%s.network.out' % (provider, distro.lower())
@@ -144,5 +151,21 @@ class TestGlean(base.BaseTestCase):
             write_handle = self.file_handle_mocks[dest].write
             write_handle.assert_called_once_with(content)
 
+        # Check hostname
+        meta_data_path = 'mnt/config/openstack/latest/meta_data.json'
+        hostname = None
+        with open(os.path.join(sample_data_path, provider,
+                               meta_data_path)) as fh:
+            meta_data = json.load(fh)
+            hostname = meta_data['name']
+
+        mock_call.assert_called_once_with(['hostname', hostname])
+        self.file_handle_mocks['/etc/hostname'].write.assert_has_calls(
+            [mock.call(hostname), mock.call('\n')])
+
+        # Check hosts entry
+        self.file_handle_mocks['/etc/hosts'].write.assert_called_once_with(
+            '127.0.1.1 %s\n' % hostname)
+
     def test_glean(self):
-        self._assert_network_output(self.distro, self.style)
+        self._assert_distro_provider(self.distro, self.style)