🐛 — Fix recurring tasks with gunicorn

CHANGELOG.md

@@ -2,6 +2,8 @@
 
 ## [Unreleased]
 
+- 🐛 — Fix recurring tasks with gunicorn
+
 ## 0.8.1
 
 Date: 2025-02-18
@@ -27,6 +29,8 @@ a new example configuration file.
 💥 You don’t need cron tasks anymore!
 Remove your old cron tasks as they will now do nothing but generating errors.
 
+NB: You may want to add `--enqueue` to `reload-config` command in your systemd file.
+
 ## 0.7.4
 
 Date: 2025-02-12

argos/server/main.py

@@ -6,6 +6,7 @@ from fastapi import FastAPI
 from fastapi.staticfiles import StaticFiles
 from fastapi_login import LoginManager
 from fastapi_utils.tasks import repeat_every
+from psutil import Process
 from sqlalchemy import create_engine, event
 from sqlalchemy.orm import sessionmaker
 
@@ -116,8 +117,20 @@ def create_manager(cookie_secret: str) -> LoginManager:
 @repeat_every(seconds=120, logger=logger)
 async def recurring_tasks() -> None:
     """Recurring DB cleanup and watch-agents tasks"""
+    # If we are using gunicorn
+    if not hasattr(app.state, "SessionLocal"):
+        parent_process = Process(os.getppid())
+        children = parent_process.children(recursive=True)
+        # Start the task only once, not for every worker
+        if children[0].pid == os.getpid():
+            # and we need to setup database engine
+            setup_database(app)
+        else:
+            return None
+
     set_log_level("info", quiet=True)
     logger.info("Start background recurring tasks")
+
     with app.state.SessionLocal() as db:
         config = app.state.config.recurring_tasks
         removed = await queries.remove_old_results(db, config.max_results)
@@ -135,6 +148,8 @@ async def recurring_tasks() -> None:
 
     logger.info("Background recurring tasks ended")
 
+    return None
+
 
 @asynccontextmanager
 async def lifespan(appli: FastAPI):

docs/installation/tl-dr.md

@@ -90,7 +90,7 @@ User=argos
 WorkingDirectory=/opt/argos/
 EnvironmentFile=/etc/default/argos-server
 ExecStartPre=/opt/argos/venv/bin/argos server migrate
-ExecStartPre=/opt/argos/venv/bin/argos server reload-config
+ExecStartPre=/opt/argos/venv/bin/argos server reload-config --enqueue
 ExecStart=/opt/argos/venv/bin/gunicorn "argos.server.main:get_application()" \\
                                        --workers \$ARGOS_SERVER_WORKERS \\
                                        --worker-class uvicorn.workers.UvicornWorker \\

pyproject.toml

@@ -33,6 +33,7 @@ dependencies = [
   "Jinja2>=3.0,<4",
   "jsonpointer>=3.0,<4",
   "passlib>=1.7.4,<2",
+  "psutil>=5.9.8,<6",
   "psycopg2-binary>=2.9,<3",
   "pydantic[email]>=2.4,<3",
   "pydantic-settings>=2.0,<3",