From 4caac3a6c77201a243ca586ccd57f02c0b561f71 Mon Sep 17 00:00:00 2001
From: Marcus van Elst <marcusvebo@gmail.com>
Date: Tue, 21 Apr 2026 10:06:35 +0200
Subject: [PATCH] =?UTF-8?q?fix:=20v0.2.8=20=E2=80=94=20init=20cooldown=20t?=
 =?UTF-8?q?o=20prevent=20repeated=20failed-login=20hammering?=
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Cache failed `_ensure_initialized` outcomes for 60 seconds so that
repeated tool calls during a credential outage (wrong password,
IP-blocked 407, DNS failure) don't keep hammering DSM. Each caller
gets the same exception raised from the cache until the cooldown
window expires, after which a fresh attempt is made.

- Adds INIT_ERROR_COOLDOWN module constant (60.0 s).
- Adds self._init_error / self._init_error_until state on DsmClient.
- Re-raises cached error inside the init lock, emits warning log on
  cache entry.

Addresses M4 from the 0.2.7 review.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
---
 pyproject.toml                           |  2 +-
 src/mcp_synology_container/dsm_client.py | 21 +++++++++++++++++++++
 uv.lock                                  |  2 +-
 3 files changed, 23 insertions(+), 2 deletions(-)

diff --git a/pyproject.toml b/pyproject.toml
index 35aa05f..b1082bf 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,6 +1,6 @@
 [project]
 name = "mcp-synology-container"
-version = "0.2.7"
+version = "0.2.8"
 description = "MCP server for Synology Container Manager"
 requires-python = ">=3.12"
 dependencies = [
diff --git a/src/mcp_synology_container/dsm_client.py b/src/mcp_synology_container/dsm_client.py
index 2c77f62..7855dae 100644
--- a/src/mcp_synology_container/dsm_client.py
+++ b/src/mcp_synology_container/dsm_client.py
@@ -27,6 +27,10 @@ logger = logging.getLogger(__name__)
 # Session error codes that trigger transparent re-auth
 _SESSION_ERROR_CODES = frozenset({106, 107, 119})
 
+# Cooldown after a failed init so repeated tool calls don't hammer DSM
+# (and don't escalate 407 "IP blocked" lockouts).
+INIT_ERROR_COOLDOWN = 60.0
+
 # Parameters to mask in debug logging
 _SENSITIVE_PARAMS = frozenset({"passwd", "_sid", "device_id", "otp_code", "device_token"})
 
@@ -111,6 +115,8 @@ class DsmClient:
         self._init_lock = asyncio.Lock()
         self._initialized = False
         self._initializing = False  # True while inside _ensure_initialized
+        self._init_error: Exception | None = None
+        self._init_error_until: float = 0.0
         logger.debug(
             "DsmClient: base_url=%s verify_ssl=%s timeout=%d",
             self._base_url,
@@ -141,6 +147,10 @@ class DsmClient:
         async with self._init_lock:
             if self._initialized:  # re-check inside lock
                 return
+            # Negative cache: re-raise cached error during cooldown window.
+            now = asyncio.get_event_loop().time()
+            if self._init_error is not None and now < self._init_error_until:
+                raise self._init_error
             self._initializing = True
             try:
                 sys.stderr.write(f"[dsm] Connecting to {self._base_url}...\n")
@@ -157,7 +167,18 @@ class DsmClient:
                     sys.stderr.write("[dsm] Auth OK\n")
                     sys.stderr.flush()
                 self._initialized = True
+                self._init_error = None
+                self._init_error_until = 0.0
                 logger.debug("Lazy init complete")
+            except Exception as e:
+                self._init_error = e
+                self._init_error_until = now + INIT_ERROR_COOLDOWN
+                logger.warning(
+                    "Lazy init failed (%s); will retry after %.0fs cooldown",
+                    type(e).__name__,
+                    INIT_ERROR_COOLDOWN,
+                )
+                raise
             finally:
                 self._initializing = False
 
diff --git a/uv.lock b/uv.lock
index ba81567..0287a4d 100644
--- a/uv.lock
+++ b/uv.lock
@@ -362,7 +362,7 @@ wheels = [
 
 [[package]]
 name = "mcp-synology-container"
-version = "0.2.7"
+version = "0.2.8"
 source = { editable = "." }
 dependencies = [
     { name = "click" },