node-proxy: log actual data delta in reporter

this adds a _dict_diff() function that computes recursive dict diff
and uses it in reporter to log the delta (truncated at 2048 chars)

Fixes: https://tracker.ceph.com/issues/74749
Signed-off-by: Guillaume Abrioux <gabrioux@ibm.com>

diff --git a/src/ceph-node-proxy/ceph_node_proxy/reporter.py b/src/ceph-node-proxy/ceph_node_proxy/reporter.py
index e9754ddfc3588b79e9d03858eda1f1ce6df09853..fc2d75a79a3aaa6f35e1afb56b9dece00da7b055 100644 (file)
--- a/src/ceph-node-proxy/ceph_node_proxy/reporter.py
+++ b/src/ceph-node-proxy/ceph_node_proxy/reporter.py
@@ -4,13 +4,12 @@ from typing import Any, Dict
 from urllib.error import HTTPError, URLError
 
 from ceph_node_proxy.protocols import SystemForReporter
-from ceph_node_proxy.util import BaseThread, get_logger, http_req
+from ceph_node_proxy.util import BaseThread, get_logger, http_req, _dict_diff
 
 DEFAULT_MAX_RETRIES = 30
 RETRY_SLEEP_SEC = 5
 HEARTBEAT_INTERVAL_SEC = 300
 
-
 class Reporter(BaseThread):
     def __init__(
         self,
@@ -65,6 +64,26 @@ class Reporter(BaseThread):
                     time.sleep(RETRY_SLEEP_SEC)
         return False
 
+    def _log_data_delta(
+        self,
+        new_data: Dict[str, Any],
+        max_log_len: int = 2048,
+    ) -> None:
+        """Compute diff between previous and new data, then log it (truncated if needed)."""
+        delta = _dict_diff(self.system.previous_data, new_data) or {}
+        delta_json = json.dumps(delta, indent=2, default=str)
+        if len(delta_json) > max_log_len:
+            delta_json = delta_json[:max_log_len] + "\n... (truncated)"
+        if self.system.previous_data:
+            self.log.info(
+                "data has changed since last iteration; delta:\n%s",
+                delta_json,
+            )
+        else:
+            # the first delta is the full data received from the system
+            # which is by definition big so we don't log it as it would be too verbose
+            self.log.info("first data received from the system.")
+
     def main(self) -> None:
         last_heartbeat = time.monotonic()
         while not self.stop:
@@ -75,10 +94,11 @@ class Reporter(BaseThread):
                     if self.system.data_ready:
                         self.log.debug("data ready to be sent to the mgr.")
                         if self.system.get_system() != self.system.previous_data:
-                            self.log.info("data has changed since last iteration.")
-                            self.data["patch"] = self.system.get_system()
+                            new_data = self.system.get_system()
+                            self._log_data_delta(new_data)
+                            self.data["patch"] = new_data
                             if self._send_with_retries():
-                                self.system.previous_data = self.system.get_system()
+                                self.system.previous_data = new_data
                             else:
                                 self.log.error(
                                     f"Failed to send data after {self.max_retries} retries; "

diff --git a/src/ceph-node-proxy/ceph_node_proxy/util.py b/src/ceph-node-proxy/ceph_node_proxy/util.py
index aa474624ae82d428784a83c2923372ebfef3ac4e..419bf18dbae6e2603875f611247e07c1eafb3481 100644 (file)
--- a/src/ceph-node-proxy/ceph_node_proxy/util.py
+++ b/src/ceph-node-proxy/ceph_node_proxy/util.py
@@ -221,3 +221,23 @@ def write_tmp_file(
     f.write(data.encode("utf-8"))
     f.flush()
     return f
+
+
+def _dict_diff(old: Any, new: Any) -> Any:
+    if old == new:
+        return None
+    if type(old) != type(new) or not isinstance(new, dict):
+        return new
+    if not isinstance(old, dict):
+        return new
+    delta: Dict[str, Any] = {}
+    for k in sorted(set(old) | set(new)):
+        if k not in old:
+            delta[k] = new[k]
+        elif k not in new:
+            delta[k] = None
+        else:
+            sub = _dict_diff(old[k], new[k])
+            if sub is not None:
+                delta[k] = sub
+    return delta if delta else None