add MessageCache and DomainNode, based on peewee ORM & SQLite

setup.cfg

@@ -79,6 +79,7 @@ testing =
     black
     isort
     flake8
+    peewee
 mqtt =
     aiomqtt<=0.1.3
     certifi
@@ -103,6 +104,8 @@ ledger =
     ledgereth==0.9.0
 docs =
     sphinxcontrib-plantuml
+cache =
+    peewee
 
 [options.entry_points]
 # Add here console scripts like:

src/aleph/sdk/conf.py

@@ -33,6 +33,15 @@ class Settings(BaseSettings):
 
     CODE_USES_SQUASHFS: bool = which("mksquashfs") is not None  # True if command exists
 
+    CACHE_DATABASE_PATH: Path = Field(
+        default=Path(":memory:"),  # can also be :memory: for in-memory caching
+        description="Path to the cache database",
+    )
+    CACHE_FILES_PATH: Path = Field(
+        default=Path("cache", "files"),
+        description="Path to the cache files",
+    )
+
     class Config:
         env_prefix = "ALEPH_"
         case_sensitive = False