Capture the early logging

_early_log prints to stdout, which is fine in some cases,
however in other cases it gets lost in the shuffle of process
launch by things like systemd.

Lets try to save everything, and re-log it so it is easy to
debug early issues.

Change-Id: I334a9073d17cccec4c669fae82edc3e388debc5c

3 files changed, 36 insertions, 2 deletions

diff --git a/ironic_python_agent/cmd/agent.py b/ironic_python_agent/cmd/agent.py
index 92530347..9ebe3006 100644
--- a/ironic_python_agent/cmd/agent.py
+++ b/ironic_python_agent/cmd/agent.py
@@ -46,7 +46,7 @@ def run():
     logger = log.getLogger(__name__)
     logger.debug("Configuration:")
     CONF.log_opt_values(logger, log.DEBUG)
-
+    utils.log_early_log_to_logger()
     agent.IronicPythonAgent(CONF.api_url,
                             agent.Host(hostname=CONF.advertise_host,
                                        port=CONF.advertise_port),
diff --git a/ironic_python_agent/tests/unit/test_utils.py b/ironic_python_agent/tests/unit/test_utils.py
index 02f2f95d..640d50ca 100644
--- a/ironic_python_agent/tests/unit/test_utils.py
+++ b/ironic_python_agent/tests/unit/test_utils.py
@@ -1195,3 +1195,26 @@ class TestCheckVirtualMedia(ironic_agent_base.IronicAgentTest):
         mock_execute.assert_called_with('lsblk', '-n', '-s', '-P', '-b',
                                         '-oKNAME,TRAN,TYPE,SIZE',
                                         '/dev/sdh')
+
+
+class TestCheckEarlyLogging(ironic_agent_base.IronicAgentTest):
+
+    @mock.patch.object(utils, 'LOG', autospec=True)
+    def test_early_logging_goes_to_logger(self, mock_log):
+        info = mock.Mock()
+        mock_log.info.side_effect = info
+        # Reset the buffer to be empty.
+        utils._EARLY_LOG_BUFFER = []
+        # Store some data via _early_log
+        utils._early_log('line 1.')
+        utils._early_log('line 2 %s', 'message')
+        expected_messages = ['line 1.',
+                             'line 2 message']
+        self.assertEqual(expected_messages, utils._EARLY_LOG_BUFFER)
+        # Test we've got data in the buffer.
+        info.assert_not_called()
+        # Test the other half of this.
+        utils.log_early_log_to_logger()
+        expected_calls = [mock.call('Early logging: %s', 'line 1.'),
+                          mock.call('Early logging: %s', 'line 2 message')]
+        info.assert_has_calls(expected_calls)
diff --git a/ironic_python_agent/utils.py b/ironic_python_agent/utils.py
index f045a4fe..dd68a526 100644
--- a/ironic_python_agent/utils.py
+++ b/ironic_python_agent/utils.py
@@ -78,6 +78,8 @@ DEVICE_EXTRACTOR = re.compile(r'^(?:(.*\d)p|(.*\D))(?:\d+)$')
 PARTED_TABLE_TYPE_REGEX = re.compile(r'^.*partition\s+table\s*:\s*(gpt|msdos)',
                                      re.IGNORECASE)
 
+_EARLY_LOG_BUFFER = []
+
 
 def execute(*cmd, **kwargs):
     """Convenience wrapper around ironic_lib's execute() method.
@@ -187,7 +189,16 @@ def _get_vmedia_params():
 
 def _early_log(msg, *args):
     """Log via printing (before oslo.log is configured)."""
-    print('ironic-python-agent:', msg % args, file=sys.stderr)
+    log_entry = msg % args
+    _EARLY_LOG_BUFFER.append(log_entry)
+    print('ironic-python-agent:', log_entry, file=sys.stderr)
+
+
+def log_early_log_to_logger():
+    """Logs early logging events to the configured logger."""
+
+    for entry in _EARLY_LOG_BUFFER:
+        LOG.info("Early logging: %s", entry)
 
 
 def _copy_config_from(path):