cc_keys_to_console: add option to disable key emission (#811)

Specifically:

ssh:                                                                            
  emit_keys_to_console: false

We also port the cc_keys_to_console cloud tests to the new integration
testing framework, and add a test for this new option.

LP: #1915460

2 files changed, 39 insertions, 0 deletions

diff --git a/cloudinit/config/cc_keys_to_console.py b/cloudinit/config/cc_keys_to_console.py
index 0f2be52b..646d1f67 100644
--- a/cloudinit/config/cc_keys_to_console.py
+++ b/cloudinit/config/cc_keys_to_console.py
@@ -51,6 +51,11 @@ def _get_helper_tool_path(distro):
 
 
 def handle(name, cfg, cloud, log, _args):
+    if util.is_false(cfg.get("ssh", {}).get("emit_keys_to_console", True)):
+        log.debug(("Skipping module named %s, "
+                   "logging of SSH host keys disabled"), name)
+        return
+
     helper_path = _get_helper_tool_path(cloud.distro)
     if not os.path.exists(helper_path):
         log.warning(("Unable to activate module %s,"
diff --git a/cloudinit/config/tests/test_keys_to_console.py b/cloudinit/config/tests/test_keys_to_console.py
new file mode 100644
index 00000000..4083fc54
--- /dev/null
+++ b/cloudinit/config/tests/test_keys_to_console.py
@@ -0,0 +1,34 @@
+"""Tests for cc_keys_to_console."""
+from unittest import mock
+
+import pytest
+
+from cloudinit.config import cc_keys_to_console
+
+
+class TestHandle:
+    """Tests for cloudinit.config.cc_keys_to_console.handle.
+
+    TODO: These tests only cover the emit_keys_to_console config option, they
+    should be expanded to cover the full functionality.
+    """
+
+    @mock.patch("cloudinit.config.cc_keys_to_console.util.multi_log")
+    @mock.patch("cloudinit.config.cc_keys_to_console.os.path.exists")
+    @mock.patch("cloudinit.config.cc_keys_to_console.subp.subp")
+    @pytest.mark.parametrize("cfg,subp_called", [
+        ({}, True),  # Default to emitting keys
+        ({"ssh": {}}, True),  # Default even if we have the parent key
+        ({"ssh": {"emit_keys_to_console": True}}, True),  # Explicitly enabled
+        ({"ssh": {"emit_keys_to_console": False}}, False),  # Disabled
+    ])
+    def test_emit_keys_to_console_config(
+        self, m_subp, m_path_exists, _m_multi_log, cfg, subp_called
+    ):
+        # Ensure we always find the helper
+        m_path_exists.return_value = True
+        m_subp.return_value = ("", "")
+
+        cc_keys_to_console.handle("name", cfg, mock.Mock(), mock.Mock(), ())
+
+        assert subp_called == (m_subp.call_count == 1)