fix: scope log filenames by service under root logs dir

backend/src/core/config/settings.py

@@ -4,7 +4,7 @@ from pathlib import Path
 from typing import ClassVar, Literal
 from urllib.parse import quote
 
-from pydantic import BaseModel, Field, computed_field, field_validator
+from pydantic import BaseModel, Field, computed_field, field_validator, model_validator
 from pydantic_settings import BaseSettings, SettingsConfigDict
 
 
@@ -21,8 +21,8 @@ class RuntimeSettings(BaseModel):
     log_rotation_max_bytes: int = 10_000_000
     log_dir: str = "logs"
     log_error_dir: str = "logs/errors"
-    log_file_name: str = "app.log"
-    log_error_file_name: str = "error.log"
+    log_file_name: str = ""
+    log_error_file_name: str = ""
     log_sensitive_fields: list[str] = Field(
         default_factory=lambda: [
             "password",
@@ -47,15 +47,20 @@ class RuntimeSettings(BaseModel):
     def lock_log_error_dir(cls, _: object) -> str:
         return "logs/errors"
 
-    @field_validator("log_file_name", mode="before")
-    @classmethod
-    def lock_log_file_name(cls, _: object) -> str:
-        return "app.log"
+    @model_validator(mode="after")
+    def ensure_service_scoped_log_file_names(self) -> "RuntimeSettings":
+        service = "".join(
+            char if char.isalnum() or char in {"-", "_"} else "-"
+            for char in self.service_name
+        ).strip("-_")
+        service_name = service or "app"
 
-    @field_validator("log_error_file_name", mode="before")
-    @classmethod
-    def lock_log_error_file_name(cls, _: object) -> str:
-        return "error.log"
+        if not self.log_file_name.strip():
+            self.log_file_name = f"{service_name}.log"
+        if not self.log_error_file_name.strip():
+            self.log_error_file_name = f"{service_name}.error.log"
+
+        return self
 
 
 class CelerySettings(BaseModel):