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):

backend/tests/e2e/test_logging_e2e.py

@@ -86,7 +86,7 @@ def test_e2e_error_logging(tmp_path: Path) -> None:
         server.should_exit = True
         thread.join(timeout=5)
 
-    error_entries = _read_json_lines(Path(tmp_path) / "errors" / "error.log")
+    error_entries = _read_json_lines(Path(tmp_path) / "errors" / "app.error.log")
     entry = next(
         item for item in error_entries if item.get("message") == "Unhandled exception"
     )

backend/tests/integration/test_fastapi_logging_integration.py

@@ -83,7 +83,7 @@ def test_exception_handler_logs_stack_and_sends_500(tmp_path: Path) -> None:
     assert response.status_code == 500
     assert response.json()["detail"] == "Internal Server Error"
 
-    error_entries = _read_json_lines(Path(tmp_path) / "errors" / "error.log")
+    error_entries = _read_json_lines(Path(tmp_path) / "errors" / "app.error.log")
     assert error_entries
     entry = error_entries[-1]
     assert entry["level"] == "error"
@@ -116,7 +116,7 @@ def test_invalid_request_id_is_replaced_and_used_in_error_context(
     response_request_id = response.headers["X-Request-ID"]
     assert response_request_id != "bad"
 
-    error_entries = _read_json_lines(Path(tmp_path) / "errors" / "error.log")
+    error_entries = _read_json_lines(Path(tmp_path) / "errors" / "app.error.log")
     assert error_entries
     entry = error_entries[-1]
     assert entry["request_id"] == response_request_id

backend/tests/unit/test_logging_settings.py

@@ -17,7 +17,7 @@ def test_runtime_settings_defaults() -> None:
     assert settings.runtime.log_dir == "logs"
     assert settings.runtime.log_error_dir == "logs/errors"
     assert settings.runtime.log_file_name == "app.log"
-    assert settings.runtime.log_error_file_name == "error.log"
+    assert settings.runtime.log_error_file_name == "app.error.log"
     assert "password" in settings.runtime.log_sensitive_fields
 
 
@@ -33,7 +33,22 @@ def test_runtime_settings_env_override(monkeypatch: MonkeyPatch) -> None:
 
     assert settings.runtime.log_dir == "logs"
     assert settings.runtime.log_error_dir == "logs/errors"
-    assert settings.runtime.log_file_name == "app.log"
-    assert settings.runtime.log_error_file_name == "error.log"
+    assert settings.runtime.log_file_name == "custom.log"
+    assert settings.runtime.log_error_file_name == "custom-error.log"
     assert settings.runtime.log_rotation == "size"
     assert settings.runtime.log_rotation_max_bytes == 2048
+
+
+def test_runtime_settings_default_file_names_follow_service_name(
+    monkeypatch: MonkeyPatch,
+) -> None:
+    monkeypatch.delenv("SOCIAL_RUNTIME__LOG_FILE_NAME", raising=False)
+    monkeypatch.delenv("SOCIAL_RUNTIME__LOG_ERROR_FILE_NAME", raising=False)
+    monkeypatch.setenv("SOCIAL_RUNTIME__SERVICE_NAME", "worker-default")
+
+    settings = Settings()
+
+    assert settings.runtime.log_dir == "logs"
+    assert settings.runtime.log_error_dir == "logs/errors"
+    assert settings.runtime.log_file_name == "worker-default.log"
+    assert settings.runtime.log_error_file_name == "worker-default.error.log"