Move warning functionality to cloudinit/warnings.py

This moves the warning code that was added specifically for
EC2 into a generic path at cloudinit/warnings.py.

It also adds support for writing warning files into the
warnings directory to be shown by Z99-cloudinit-warnings.sh.

3 files changed, 121 insertions, 42 deletions

diff --git a/cloudinit/helpers.py b/cloudinit/helpers.py
index 38f5f899..7435d58d 100644
--- a/cloudinit/helpers.py
+++ b/cloudinit/helpers.py
@@ -340,6 +340,7 @@ class Paths(object):
             "vendordata": "vendor-data.txt.i",
             "instance_id": ".instance-id",
             "manual_clean_marker": "manual-clean",
+            "warnings": "warnings",
         }
         # Set when a datasource becomes active
         self.datasource = ds
diff --git a/cloudinit/sources/DataSourceEc2.py b/cloudinit/sources/DataSourceEc2.py
index c7df8060..6f01a139 100644
--- a/cloudinit/sources/DataSourceEc2.py
+++ b/cloudinit/sources/DataSourceEc2.py
@@ -9,7 +9,6 @@
 # This file is part of cloud-init. See LICENSE file for license information.
 
 import os
-import textwrap
 import time
 
 from cloudinit import ec2_utils as ec2
@@ -17,6 +16,7 @@ from cloudinit import log as logging
 from cloudinit import sources
 from cloudinit import url_helper as uhelp
 from cloudinit import util
+from cloudinit import warnings
 
 LOG = logging.getLogger(__name__)
 
@@ -224,7 +224,8 @@ class DataSourceEc2(sources.DataSource):
             return
         if self.cloud_platform == Platforms.UNKNOWN:
             warn_if_necessary(
-                util.get_cfg_by_path(cfg, STRICT_ID_PATH, STRICT_ID_DEFAULT))
+                util.get_cfg_by_path(cfg, STRICT_ID_PATH, STRICT_ID_DEFAULT),
+                cfg)
 
 
 def read_strict_mode(cfgval, default):
@@ -265,7 +266,7 @@ def parse_strict_mode(cfgval):
     return mode, sleep
 
 
-def warn_if_necessary(cfgval):
+def warn_if_necessary(cfgval, cfg):
     try:
         mode, sleep = parse_strict_mode(cfgval)
     except ValueError as e:
@@ -275,45 +276,7 @@ def warn_if_necessary(cfgval):
     if mode == "false":
         return
 
-    show_warning(sleep)
-
-
-def show_warning(sleep):
-    message = textwrap.dedent("""
-        ****************************************************************
-        # This system is using the EC2 Metadata Service, but does not  #
-        # appear to be running on Amazon EC2 or one of cloud-init's    #
-        # known platforms that provide a EC2 Metadata service. In the  #
-        # future, cloud-init may stop reading metadata from the EC2    #
-        # Metadata Service unless the platform can be identified       #
-        #                                                              #
-        # If you are seeing this message, please file a bug against    #
-        # cloud-init at https://bugs.launchpad.net/cloud-init/+filebug #
-        # Make sure to include the cloud provider your instance is     #
-        # running on.                                                  #
-        #                                                              #
-        # For more information see                                     #
-        #   https://bugs.launchpad.net/cloud-init/+bug/1660385         #
-        #                                                              #
-        # After you have filed a bug, you can disable this warning by  #
-        # launching your instance with the cloud-config below, or      #
-        # putting that content into                                    #
-        #    /etc/cloud/cloud.cfg.d/99-ec2-datasource.cfg              #
-        #                                                              #
-        # #cloud-config                                                #
-        # datasource:                                                  #
-        #  Ec2:                                                        #
-        #   strict_id: false                                           #
-        #                                                              #
-        """)
-    closemsg = ""
-    if sleep:
-        closemsg = "  [sleeping for %d seconds]  " % sleep
-    message += closemsg.center(64, "*")
-    print(message)
-    LOG.warn(message)
-    if sleep:
-        time.sleep(sleep)
+    warnings.show_warning('non_ec2_md', cfg, mode=True, sleep=sleep)
 
 
 def identify_aws(data):
diff --git a/cloudinit/warnings.py b/cloudinit/warnings.py
new file mode 100644
index 00000000..77c092f9
--- /dev/null
+++ b/cloudinit/warnings.py
@@ -0,0 +1,115 @@
+# This file is part of cloud-init. See LICENSE file for license information.
+
+from cloudinit import helpers
+from cloudinit import log as logging
+from cloudinit import util
+
+import os
+import time
+
+LOG = logging.getLogger()
+
+WARNINGS = {
+    'non_ec2_md': """
+This system is using the EC2 Metadata Service, but does not appear to
+be running on Amazon EC2 or one of cloud-init's known platforms that
+provide a EC2 Metadata service. In the future, cloud-init may stop
+reading metadata from the EC2 Metadata Service unless the platform can
+be identified.
+
+If you are seeing this message, please file a bug against
+cloud-init at
+   https://bugs.launchpad.net/cloud-init/+filebug?field.tags=dsid
+Make sure to include the cloud provider your instance is
+running on.
+
+For more information see
+  https://bugs.launchpad.net/bugs/1660385
+
+After you have filed a bug, you can disable this warning by
+launching your instance with the cloud-config below, or
+putting that content into
+   /etc/cloud/cloud.cfg.d/99-ec2-datasource.cfg
+
+#cloud-config
+datasource:
+ Ec2:
+  strict_id: false""",
+}
+
+
+def _get_warn_dir(cfg):
+    paths = helpers.Paths(
+        path_cfgs=cfg.get('system_info', {}).get('paths', {}))
+    return paths.get_ipath_cur('warnings')
+
+
+def _load_warn_cfg(cfg, name, mode=True, sleep=None):
+    # parse cfg['warnings']['name'] returning boolean, sleep
+    # expected value is form of:
+    #   (on|off|true|false|sleep)[,sleeptime]
+    # boolean True == on, False == off
+    default = (mode, sleep)
+    if not cfg or not isinstance(cfg, dict):
+        return default
+
+    ncfg = util.get_cfg_by_path(cfg, ('warnings', name))
+    if ncfg is None:
+        return default
+
+    if ncfg in ("on", "true", True):
+        return True, None
+
+    if ncfg in ("off", "false", False):
+        return False, None
+
+    mode, _, csleep = ncfg.partition(",")
+    if mode != "sleep":
+        return default
+
+    if csleep:
+        try:
+            sleep = int(csleep)
+        except ValueError:
+            return default
+
+    return True, sleep
+
+
+def show_warning(name, cfg=None, sleep=None, mode=True, **kwargs):
+    # kwargs are used for .format of the message.
+    # sleep and mode are default values used if
+    #   cfg['warnings']['name'] is not present.
+    if cfg is None:
+        cfg = {}
+
+    mode, sleep = _load_warn_cfg(cfg, name, mode=mode, sleep=sleep)
+    if not mode:
+        return
+
+    msg = WARNINGS[name].format(**kwargs)
+    msgwidth = 70
+    linewidth = msgwidth + 4
+
+    fmt = "# %%-%ds #" % msgwidth
+    topline = "*" * linewidth + "\n"
+    fmtlines = []
+    for line in msg.strip("\n").splitlines():
+        fmtlines.append(fmt % line)
+
+    closeline = topline
+    if sleep:
+        sleepmsg = "  [sleeping for %d seconds]  " % sleep
+        closeline = sleepmsg.center(linewidth, "*") + "\n"
+
+    util.write_file(
+        os.path.join(_get_warn_dir(cfg), name),
+        topline + "\n".join(fmtlines) + "\n" + topline)
+
+    LOG.warn(topline + "\n".join(fmtlines) + "\n" + closeline)
+
+    if sleep:
+        LOG.debug("sleeping %d seconds for warning '%s'" % (sleep, name))
+        time.sleep(sleep)
+
+# vi: ts=4 expandtab