Improve detection of snappy to include os-release and kernel cmdline.

Recent core snap images (edge channel revision 1886) do not contain the
previously known files used to detect that a system is ubuntu core.

The changes here are to look in 2 additional locations to determine
if a system is snappy.

LP: #1689944

2 files changed, 38 insertions, 30 deletions

diff --git a/cloudinit/net/cmdline.py b/cloudinit/net/cmdline.py
index 61e23697..38b27a52 100755
--- a/cloudinit/net/cmdline.py
+++ b/cloudinit/net/cmdline.py
@@ -9,41 +9,12 @@ import base64
 import glob
 import gzip
 import io
-import shlex
-import sys
-
-import six
 
 from . import get_devicelist
 from . import read_sys_net_safe
 
 from cloudinit import util
 
-PY26 = sys.version_info[0:2] == (2, 6)
-
-
-def _shlex_split(blob):
-    if PY26 and isinstance(blob, six.text_type):
-        # Older versions don't support unicode input
-        blob = blob.encode("utf8")
-    return shlex.split(blob)
-
-
-def _load_shell_content(content, add_empty=False, empty_val=None):
-    """Given shell like syntax (key=value\nkey2=value2\n) in content
-       return the data in dictionary form.  If 'add_empty' is True
-       then add entries in to the returned dictionary for 'VAR='
-       variables.  Set their value to empty_val."""
-    data = {}
-    for line in _shlex_split(content):
-        key, value = line.split("=", 1)
-        if not value:
-            value = empty_val
-        if add_empty or value:
-            data[key] = value
-
-    return data
-
 
 def _klibc_to_config_entry(content, mac_addrs=None):
     """Convert a klibc written shell content file to a 'config' entry
@@ -63,7 +34,7 @@ def _klibc_to_config_entry(content, mac_addrs=None):
     if mac_addrs is None:
         mac_addrs = {}
 
-    data = _load_shell_content(content)
+    data = util.load_shell_content(content)
     try:
         name = data['DEVICE'] if 'DEVICE' in data else data['DEVICE6']
     except KeyError:
diff --git a/cloudinit/util.py b/cloudinit/util.py
index 27a98330..67ff7ba3 100644
--- a/cloudinit/util.py
+++ b/cloudinit/util.py
@@ -24,6 +24,7 @@ import platform
 import pwd
 import random
 import re
+import shlex
 import shutil
 import socket
 import stat
@@ -75,6 +76,7 @@ CONTAINER_TESTS = (['systemd-detect-virt', '--quiet', '--container'],
 PROC_CMDLINE = None
 
 _LSB_RELEASE = {}
+PY26 = sys.version_info[0:2] == (2, 6)
 
 
 def get_architecture(target=None):
@@ -2424,6 +2426,18 @@ def system_is_snappy():
     # channel.ini is configparser loadable.
     # snappy will move to using /etc/system-image/config.d/*.ini
     # this is certainly not a perfect test, but good enough for now.
+    orpath = "/etc/os-release"
+    try:
+        orinfo = load_shell_content(load_file(orpath, quiet=True))
+        if orinfo.get('ID', '').lower() == "ubuntu-core":
+            return True
+    except ValueError as e:
+        LOG.warning("Unexpected error loading '%s': %s", orpath, e)
+
+    cmdline = get_cmdline()
+    if 'snap_core=' in cmdline:
+        return True
+
     content = load_file("/etc/system-image/channel.ini", quiet=True)
     if 'ubuntu-core' in content.lower():
         return True
@@ -2470,4 +2484,27 @@ def rootdev_from_cmdline(cmdline):
     return "/dev/" + found
 
 
+def load_shell_content(content, add_empty=False, empty_val=None):
+    """Given shell like syntax (key=value\nkey2=value2\n) in content
+       return the data in dictionary form.  If 'add_empty' is True
+       then add entries in to the returned dictionary for 'VAR='
+       variables.  Set their value to empty_val."""
+
+    def _shlex_split(blob):
+        if PY26 and isinstance(blob, six.text_type):
+            # Older versions don't support unicode input
+            blob = blob.encode("utf8")
+        return shlex.split(blob)
+
+    data = {}
+    for line in _shlex_split(content):
+        key, value = line.split("=", 1)
+        if not value:
+            value = empty_val
+        if add_empty or value:
+            data[key] = value
+
+    return data
+
+
 # vi: ts=4 expandtab