adding notes

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dgtlmoon
2026-02-07 03:41:02 +01:00
parent c6744f6969
commit a89c30f882
3 changed files with 207 additions and 4 deletions
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"""
Tag/Group domain model for organizing and overriding watch settings.
ARCHITECTURE NOTE: Configuration Override Hierarchy
===================================================
Tags can override Watch settings when overrides_watch=True.
Current implementation requires manual checking in processors:
for tag_uuid in watch.get('tags'):
tag = datastore['settings']['application']['tags'][tag_uuid]
if tag.get('overrides_watch'):
restock_settings = tag.get('restock_settings', {})
break
With Pydantic, this would be automatic via chain resolution:
Watch → Tag (first with overrides_watch) → Global
See: Watch.py model docstring for full Pydantic architecture explanation
See: processors/restock_diff/processor.py:184-192 for current manual implementation
"""
from changedetectionio.model import watch_base
class model(watch_base):
"""
Tag domain model - groups watches and can override their settings.
Tags inherit from watch_base to reuse all the same fields as Watch.
When overrides_watch=True, tag settings take precedence over watch settings
for all watches in this tag/group.
Fields:
overrides_watch (bool): If True, this tag's settings override watch settings
title (str): Display name for this tag/group
uuid (str): Unique identifier
... (all fields from watch_base can be set as tag-level overrides)
Resolution order when overrides_watch=True:
Watch.field → Tag.field (if overrides_watch) → Global.field
"""
def __init__(self, *arg, **kw):
# Store datastore reference (optional for Tags, but good for consistency)
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"""
Watch domain model for change detection monitoring.
ARCHITECTURE NOTE: Configuration Override Hierarchy
===================================================
This module implements Watch objects that inherit from dict (technical debt).
The dream architecture would use Pydantic for:
1. CHAIN RESOLUTION (Watch → Tag → Global Settings)
- Current: Manual resolution scattered across codebase
- Future: @computed_field properties with automatic resolution
- Examples: resolved_fetch_backend, resolved_restock_settings, etc.
2. DATABASE BACKEND ABSTRACTION
- Current: Domain model tightly coupled to file-based JSON storage
- Future: Domain model (Pydantic) separate from persistence layer
- Enables: Easy migration to PostgreSQL, MongoDB, etc.
3. TYPE SAFETY & VALIDATION
- Current: Dict access with no compile-time checks
- Future: Type hints, IDE autocomplete, validation at boundaries
See class model docstring for detailed explanation and examples.
See: processors/restock_diff/processor.py:184-192 for manual resolution example
"""
import gc
from copy import copy
@@ -104,6 +130,99 @@ def _brotli_save(contents, filepath, mode=None, fallback_uncompressed=False):
class model(watch_base):
"""
Watch domain model for monitoring URL changes.
Inherits from watch_base (which inherits dict) - see watch_base docstring for field documentation.
## Configuration Override Hierarchy (Chain Resolution)
The dream architecture uses a 3-level resolution chain:
Watch settings → Tag/Group settings → Global settings
Current implementation is MANUAL (see processor.py:184-192 for example):
- Processors manually check watch.get('field')
- Then loop through watch.tags to find first tag with overrides_watch=True
- Finally fall back to datastore['settings']['application']['field']
FUTURE: Pydantic-based chain resolution would enable:
```python
# Instead of manual resolution in every processor:
restock_settings = watch.get('restock_settings', {})
for tag_uuid in watch.get('tags'):
tag = datastore['settings']['application']['tags'][tag_uuid]
if tag.get('overrides_watch'):
restock_settings = tag.get('restock_settings', {})
break
# Clean computed properties with automatic resolution:
@computed_field
def resolved_restock_settings(self) -> dict:
if self.restock_settings:
return self.restock_settings
for tag_uuid in self.tags:
tag = self._datastore.get_tag(tag_uuid)
if tag.overrides_watch and tag.restock_settings:
return tag.restock_settings
return self._datastore.settings.restock_settings or {}
# Usage: watch.resolved_restock_settings (automatic, type-safe, tested once)
```
Benefits of Pydantic migration:
1. Single source of truth for resolution logic (not scattered across processors)
2. Type safety + IDE autocomplete (watch.resolved_fetch_backend vs dict navigation)
3. Database backend abstraction (domain model separate from persistence)
4. Automatic validation at boundaries
5. Self-documenting via type hints
6. Easy to test resolution independently
Resolution chain examples that would benefit:
- fetch_backend: watch → tag → global (see get_fetch_backend property)
- notification_urls: watch → tag → global
- time_between_check: watch → global (see threshold_seconds)
- restock_settings: watch → tag (see processors/restock_diff/processor.py:184-192)
- history_snapshot_max_length: watch → global (see save_history_blob:550-556)
- All processor_config_* settings could use tag overrides
## Database Backend Abstraction with Pydantic
Current: Watch inherits dict, tightly coupled to file-based JSON storage
Future: Domain model (Watch) separate from persistence layer
```python
# Domain model (database-agnostic)
class Watch(BaseModel):
uuid: str
url: str
# ... validation, business logic
# Pluggable backends
class DataStoreBackend(ABC):
def save_watch(self, watch: Watch): ...
def load_watch(self, uuid: str) -> Watch: ...
# Implementations: FileBackend, MongoBackend, PostgresBackend, etc.
```
This would enable:
- Easy migration between storage backends (file → postgres → mongodb)
- Pydantic handles serialization/deserialization automatically
- Domain logic stays clean (no storage concerns in Watch methods)
## Migration Path
Given existing codebase, incremental migration recommended:
1. Create Pydantic models alongside existing dict-based models
2. Add .to_pydantic() / .from_pydantic() bridge methods
3. Gradually migrate code to use Pydantic models
4. Remove dict inheritance once migration complete
See: watch_base docstring for technical debt discussion
See: processors/restock_diff/processor.py:184-192 for manual resolution example
See: Watch.py:550-556 for nested dict navigation that would become watch.resolved_*
"""
__newest_history_key = None
__history_n = 0
jitter_seconds = 0
@@ -243,8 +362,30 @@ class model(watch_base):
@property
def get_fetch_backend(self):
"""
Like just using the `fetch_backend` key but there could be some logic
:return:
Get the fetch backend for this watch with special case handling.
CHAIN RESOLUTION OPPORTUNITY:
Currently returns watch.fetch_backend directly, but doesn't implement
Watch → Tag → Global resolution chain. With Pydantic:
@computed_field
def resolved_fetch_backend(self) -> str:
# Special case: PDFs always use html_requests
if self.is_pdf:
return 'html_requests'
# Watch override
if self.fetch_backend and self.fetch_backend != 'system':
return self.fetch_backend
# Tag override (first tag with overrides_watch=True wins)
for tag_uuid in self.tags:
tag = self._datastore.get_tag(tag_uuid)
if tag.overrides_watch and tag.fetch_backend:
return tag.fetch_backend
# Global default
return self._datastore.settings.fetch_backend
"""
# Maybe also if is_image etc?
# This is because chrome/playwright wont render the PDF in the browser and we will just fetch it and use pdf2html to see the text.
@@ -546,7 +687,12 @@ class model(watch_base):
self.__newest_history_key = timestamp
self.__history_n += 1
# MANUAL CHAIN RESOLUTION: Watch → Global
# With Pydantic, this would become: maxlen = watch.resolved_history_snapshot_max_length
# @computed_field def resolved_history_snapshot_max_length(self) -> Optional[int]:
# if self.history_snapshot_max_length: return self.history_snapshot_max_length
# if tag := self._get_override_tag(): return tag.history_snapshot_max_length
# return self._datastore.settings.history_snapshot_max_length
maxlen = (
self.get('history_snapshot_max_length')
or (self.__datastore and self.__datastore['settings']['application'].get('history_snapshot_max_length'))
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@@ -13,13 +13,33 @@ class watch_base(dict):
Dict inheritance is legacy technical debt that should be refactored to a proper
domain model (e.g., Pydantic BaseModel) for better type safety and validation.
TODO: Migrate to Pydantic BaseModel or dataclass for:
TODO: Migrate to Pydantic BaseModel for:
- Type safety and IDE autocomplete
- Automatic validation
- Clear separation between domain model and serialization
- Database backend abstraction (file → postgres → mongodb)
- Configuration override chain resolution (Watch → Tag → Global)
- Immutability options
- Better testing
CHAIN RESOLUTION ARCHITECTURE:
The dream is a 3-level override hierarchy:
Watch settings → Tag/Group settings → Global settings
Current implementation: MANUAL resolution scattered across codebase
- Processors manually check watch.get('field')
- Loop through tags to find overrides_watch=True
- Fall back to datastore['settings']['application']['field']
Pydantic implementation: AUTOMATIC resolution via @computed_field
- Single source of truth for each setting's resolution logic
- Type-safe, testable, self-documenting
- Example: watch.resolved_fetch_backend (instead of nested dict navigation)
See: Watch.py model docstring for detailed Pydantic architecture plan
See: Tag.py model docstring for tag override explanation
See: processors/restock_diff/processor.py:184-192 for current manual example
Core Fields:
uuid (str): Unique identifier for this watch (auto-generated)
url (str): Target URL to monitor for changes