From 896cd8c41ed330efad6e0d3a3ae84c92e7281069 Mon Sep 17 00:00:00 2001
From: Eric Callahan <arksine.code@gmail.com>
Date: Thu, 25 Jan 2024 07:51:30 -0500
Subject: [PATCH] klippy_connection: exclude configfile attrs from subscription
 cache

The configfile "config" and "settings" attributes never change, and
therefore do not need to be stored in the subscription cache.  They
can be significantly large, so this change can free up some memory
on low resource systems.

Signed-off-by:  Eric Callahan <arksine.code@gmail.com>
---
 moonraker/components/klippy_connection.py | 34 +++++++++++++++--------
 1 file changed, 23 insertions(+), 11 deletions(-)

diff --git a/moonraker/components/klippy_connection.py b/moonraker/components/klippy_connection.py
index 0694838..31b1ef8 100644
--- a/moonraker/components/klippy_connection.py
+++ b/moonraker/components/klippy_connection.py
@@ -49,6 +49,12 @@ RESERVED_ENDPOINTS = [
     "register_remote_method",
 ]
 
+# Items to exclude from the subscription cache.  They never change and can be
+# quite large.
+CACHE_EXCLUSIONS = {
+    "configfile": ["config", "settings"]
+}
+
 INIT_TIME = .25
 LOG_ATTEMPT_INTERVAL = int(2. / INIT_TIME + .5)
 MAX_LOG_ATTEMPTS = 10 * LOG_ATTEMPT_INTERVAL
@@ -586,16 +592,6 @@ class KlippyConnection:
                     "No connection associated with subscription request"
                 )
             requested_sub: Subscription = args.get('objects', {})
-            if self.server.is_verbose_enabled() and "configfile" in requested_sub:
-                cfg_sub = requested_sub["configfile"]
-                if (
-                    cfg_sub is None or "config" in cfg_sub or "settings" in cfg_sub
-                ):
-                    logging.debug(
-                        f"Detected 'configfile: {cfg_sub}' subscription.  The "
-                        "'config' and 'status' fields in this object do not change "
-                        "and substantially increase cache size."
-                    )
             all_subs: Subscription = dict(requested_sub)
             # Build the subscription request from a superset of all client subscriptions
             for sub in self.subscriptions.values():
@@ -627,7 +623,23 @@ class KlippyConnection:
                             continue
                         if value != cached_status[field_name]:
                             status_diff.setdefault(obj, {})[field_name] = value
-                self.subscription_cache[obj] = fields
+                if obj in CACHE_EXCLUSIONS:
+                    # Make a shallow copy so we can pop off fields we want to
+                    # exclude from the cache without modifying the return value
+                    fields_to_cache = dict(fields)
+                    removed: List[str] = []
+                    for excluded_field in CACHE_EXCLUSIONS[obj]:
+                        if excluded_field in fields_to_cache:
+                            removed.append(excluded_field)
+                            del fields_to_cache[excluded_field]
+                    if removed:
+                        logging.debug(
+                            "Removed excluded fields from subscription cache: "
+                            f"{obj}: {removed}"
+                        )
+                    self.subscription_cache[obj] = fields_to_cache
+                else:
+                    self.subscription_cache[obj] = fields
                 # Prune Response
                 if obj in requested_sub:
                     valid_fields = requested_sub[obj]