sources/azure: refactor ssh key handling (#1248)

Split _get_public_ssh_keys_and_source() into
_get_public_keys_from_imds() and _get_public_keys_from_ovf().

Set _get_public_keys_from_imds() to take a parameter of the
IMDS metadata rather than assuming it is already set in
self.metadata.  This will allow us to move negotation into
local phase where self.metadata may not be set yet.  Update this
method to raise KeyError if IMDS metadata is missing/malformed,
and ValueError if SSH key format is not supported.  Update
get_public_ssh_keys() to catch these errors and fall back to the
OVF/Wireserver keys as needed.

To improve clarity, update register_with_azure_and_fetch_data()
to return the list of SSH keys, rather than bundling them into
a dictionary for updating against the metadata dictionary.

There should be no change in behavior with this refactor.

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

1 files changed, 3 insertions, 2 deletions

diff --git a/cloudinit/sources/helpers/azure.py b/cloudinit/sources/helpers/azure.py
index 8e8f5ce5..ec6ab80c 100755
--- a/cloudinit/sources/helpers/azure.py
+++ b/cloudinit/sources/helpers/azure.py
@@ -12,6 +12,7 @@ import zlib
 from contextlib import contextmanager
 from datetime import datetime
 from errno import ENOENT
+from typing import List, Optional
 from xml.etree import ElementTree
 from xml.sax.saxutils import escape
 
@@ -1004,7 +1005,7 @@ class WALinuxAgentShim:
     @azure_ds_telemetry_reporter
     def register_with_azure_and_fetch_data(
         self, pubkey_info=None, iso_dev=None
-    ) -> dict:
+    ) -> Optional[List[str]]:
         """Gets the VM's GoalState from Azure, uses the GoalState information
         to report ready/send the ready signal/provisioning complete signal to
         Azure, and then uses pubkey_info to filter and obtain the user's
@@ -1037,7 +1038,7 @@ class WALinuxAgentShim:
             self.eject_iso(iso_dev)
 
         health_reporter.send_ready_signal()
-        return {"public-keys": ssh_keys}
+        return ssh_keys
 
     @azure_ds_telemetry_reporter
     def register_with_azure_and_report_failure(self, description: str) -> None: