sources/azure: consolidate DHCP variants to EphemeralDHCPv4WithReporting (#1190)

- Update EphemeralDHCPv4WithReporting to subclass EphemeralDHCPv4 for
  consistency (non-functional change).

- Replace all usage of EphemeralDHCPv4 with EphemeralDHCPv4WithReporting.

- Converging to one DHCP class exposed an issue with ExitStack patches
  being mixed with decorators.  Specifically, it appeared that tests
  that did not enable azure.EphemeralDHCPv4WithReporting mocks had it
  applied anyways from previous tests.

  Presumably ExitStack was overwriting the actual value with the
  mock provided by the decorator?  For now, remove some mock patches
  that trigger failures, but future work should move towards a
  consistent approach to prevent undetected effects.

Signed-off-by: Chris Patterson <cpatterson@microsoft.com>

2 files changed, 14 insertions, 33 deletions

diff --git a/cloudinit/sources/DataSourceAzure.py b/cloudinit/sources/DataSourceAzure.py
index 280cdf50..22435284 100755
--- a/cloudinit/sources/DataSourceAzure.py
+++ b/cloudinit/sources/DataSourceAzure.py
@@ -23,7 +23,6 @@ from cloudinit import log as logging
 from cloudinit import net, sources, ssh_util, subp, util
 from cloudinit.event import EventScope, EventType
 from cloudinit.net import device_driver
-from cloudinit.net.dhcp import EphemeralDHCPv4
 from cloudinit.reporting import events
 from cloudinit.sources.helpers import netlink
 from cloudinit.sources.helpers.azure import (
@@ -32,7 +31,6 @@ from cloudinit.sources.helpers.azure import (
     azure_ds_reporter,
     azure_ds_telemetry_reporter,
     build_minimal_ovf,
-    dhcp_log_cb,
     get_boot_telemetry,
     get_metadata_from_fabric,
     get_system_info,
@@ -946,20 +944,10 @@ class DataSourceAzure(sources.DataSource):
         # VM provisioning if there is any DHCP failure when trying to determine
         # the primary NIC.
         try:
-            with events.ReportEventStack(
-                name="obtain-dhcp-lease",
-                description=(
-                    "obtain dhcp lease for %s when attempting to "
-                    "determine primary NIC during reprovision of "
-                    "a pre-provisioned VM"
-                )
-                % ifname,
-                parent=azure_ds_reporter,
-            ):
-                dhcp_ctx = EphemeralDHCPv4(
-                    iface=ifname, dhcp_log_func=dhcp_log_cb
-                )
-                dhcp_ctx.obtain_lease()
+            dhcp_ctx = EphemeralDHCPv4WithReporting(
+                azure_ds_reporter, iface=ifname
+            )
+            dhcp_ctx.obtain_lease()
         except Exception as e:
             report_diagnostic_event(
                 "Giving up. Failed to obtain dhcp lease "
@@ -1234,15 +1222,10 @@ class DataSourceAzure(sources.DataSource):
                 if not is_ephemeral_ctx_present:
                     # Save our EphemeralDHCPv4 context to avoid repeated dhcp
                     # later when we report ready
-                    with events.ReportEventStack(
-                        name="obtain-dhcp-lease",
-                        description="obtain dhcp lease",
-                        parent=azure_ds_reporter,
-                    ):
-                        self._ephemeral_dhcp_ctx = EphemeralDHCPv4(
-                            dhcp_log_func=dhcp_log_cb
-                        )
-                        lease = self._ephemeral_dhcp_ctx.obtain_lease()
+                    self._ephemeral_dhcp_ctx = EphemeralDHCPv4WithReporting(
+                        azure_ds_reporter
+                    )
+                    lease = self._ephemeral_dhcp_ctx.obtain_lease()
 
                 if vnet_switched:
                     dhcp_attempts += 1
diff --git a/cloudinit/sources/helpers/azure.py b/cloudinit/sources/helpers/azure.py
index 50058fe0..e0a1abb6 100755
--- a/cloudinit/sources/helpers/azure.py
+++ b/cloudinit/sources/helpers/azure.py
@@ -1243,11 +1243,12 @@ def dhcp_log_cb(out, err):
     )
 
 
-class EphemeralDHCPv4WithReporting:
-    def __init__(self, reporter, nic=None):
+class EphemeralDHCPv4WithReporting(EphemeralDHCPv4):
+    def __init__(self, reporter, iface=None):
         self.reporter = reporter
-        self.ephemeralDHCPv4 = EphemeralDHCPv4(
-            iface=nic, dhcp_log_func=dhcp_log_cb
+
+        super(EphemeralDHCPv4WithReporting, self).__init__(
+            iface=iface, dhcp_log_func=dhcp_log_cb
         )
 
     def __enter__(self):
@@ -1256,10 +1257,7 @@ class EphemeralDHCPv4WithReporting:
             description="obtain dhcp lease",
             parent=self.reporter,
         ):
-            return self.ephemeralDHCPv4.__enter__()
-
-    def __exit__(self, excp_type, excp_value, excp_traceback):
-        self.ephemeralDHCPv4.__exit__(excp_type, excp_value, excp_traceback)
+            return super(EphemeralDHCPv4WithReporting, self).__enter__()
 
 
 # vi: ts=4 expandtab