startup fixes: (#793)

- don't run migrations on first init, just set to CURR_DB_VERSION
- implement 'run once lock' with mkdir/rmdir
- move register_exit_handler() to utils
- remove old run once handler

backend/btrixcloud/db.py

@@ -10,7 +10,10 @@ import motor.motor_asyncio
 from pydantic import BaseModel, UUID4
 from pymongo.errors import InvalidName
 
-from .worker import by_one_worker
+from .migrations import BaseMigration
+
+
+CURR_DB_VERSION = "0005"
 
 
 # ============================================================================
@@ -47,7 +50,6 @@ def init_db():
 
 
 # ============================================================================
-@by_one_worker("/app/btrixcloud/worker-pid.file")
 async def update_and_prepare_db(
     # pylint: disable=R0913
     mdb,
@@ -64,9 +66,9 @@ async def update_and_prepare_db(
     - Create/update superuser
     - Create/update default org
 
-    Run all tasks in order in a single worker.
     """
-    if await run_db_migrations(mdb):
+    print("Database setup started", flush=True)
+    if await run_db_migrations(mdb, user_manager):
         await drop_indexes(mdb)
     await create_indexes(org_ops, crawl_config_ops, coll_ops, invite_ops)
     await user_manager.create_super_user()
@@ -75,8 +77,19 @@ async def update_and_prepare_db(
 
 
 # ============================================================================
-async def run_db_migrations(mdb):
+async def run_db_migrations(mdb, user_manager):
     """Run database migrations."""
+
+    # if first run, just set version and exit
+    if not await user_manager.get_superuser():
+        base_migration = BaseMigration(mdb, CURR_DB_VERSION)
+        await base_migration.set_db_version()
+        print(
+            "New DB, no migration needed, set version to: " + CURR_DB_VERSION,
+            flush=True,
+        )
+        return False
+
     migrations_run = False
     migrations_path = "/app/btrixcloud/migrations"
     module_files = [

backend/btrixcloud/main.py

@@ -3,9 +3,8 @@ main file for browsertrix-api system
 supports docker and kubernetes based deployments of multiple browsertrix-crawlers
 """
 import os
-import signal
-import sys
 import asyncio
+import sys
 
 from fastapi import FastAPI
 from fastapi.routing import APIRouter
@@ -26,8 +25,8 @@ from .colls import init_collections_api
 from .crawls import init_crawls_api
 
 from .crawlmanager import CrawlManager
+from .utils import run_once_lock, register_exit_handler
 
-# pylint: disable=duplicate-code
 
 API_PREFIX = "/api"
 app_root = FastAPI(
@@ -111,11 +110,13 @@ def main():
 
     crawl_config_ops.set_coll_ops(coll_ops)
 
-    asyncio.create_task(
-        update_and_prepare_db(
-            mdb, user_manager, org_ops, crawl_config_ops, coll_ops, invites
+    # run only in first worker
+    if run_once_lock("btrix-init-db"):
+        asyncio.create_task(
+            update_and_prepare_db(
+                mdb, user_manager, org_ops, crawl_config_ops, coll_ops, invites
+            )
         )
-    )
 
     app.include_router(org_ops.router)
 
@@ -140,13 +141,5 @@ def main():
 @app_root.on_event("startup")
 async def startup():
     """init on startup"""
-    loop = asyncio.get_running_loop()
-    loop.add_signal_handler(signal.SIGTERM, exit_handler)
-
+    register_exit_handler()
     main()
-
-
-def exit_handler():
-    """sigterm handler"""
-    print("SIGTERM received, exiting")
-    sys.exit(1)

backend/btrixcloud/main_op.py

@@ -1,21 +1,16 @@
 """ entrypoint module for operator """
 
-import signal
-import sys
-import asyncio
 
 from fastapi import FastAPI
+
 from .operator import init_operator_webhook
 
+from .utils import register_exit_handler
 
-API_PREFIX = "/api"
-app_root = FastAPI(
-    docs_url=API_PREFIX + "/docs",
-    redoc_url=API_PREFIX + "/redoc",
-    openapi_url=API_PREFIX + "/openapi.json",
-)
+app_root = FastAPI()
 
 
+# ============================================================================
 def main():
     """main init"""
     init_operator_webhook(app_root)
@@ -25,13 +20,5 @@ def main():
 @app_root.on_event("startup")
 async def startup():
     """init on startup"""
-    loop = asyncio.get_running_loop()
-    loop.add_signal_handler(signal.SIGTERM, exit_handler)
-
+    register_exit_handler()
     main()
-
-
-def exit_handler():
-    """sigterm handler"""
-    print("SIGTERM received, exiting")
-    sys.exit(1)

backend/btrixcloud/main_scheduled_job.py

@@ -8,6 +8,7 @@ from .k8sapi import K8sAPI
 from .db import init_db
 from .crawlconfigs import get_crawl_config, inc_crawl_count
 from .crawls import add_new_crawl
+from .utils import register_exit_handler
 
 
 # ============================================================================
@@ -58,4 +59,5 @@ def main():
 
 
 if __name__ == "__main__":
+    register_exit_handler()
     main()

backend/btrixcloud/users.py

@@ -156,6 +156,10 @@ class UserManager(BaseUserManager[UserCreate, UserDB]):
         )
         return await cursor.to_list(length=1000)
 
+    async def get_superuser(self):
+        """return current superuser, if any"""
+        return await self.user_db.collection.find_one({"is_superuser": True})
+
     async def create_super_user(self):
         """Initialize a super user from env vars"""
         email = os.environ.get("SUPERUSER_EMAIL")
@@ -167,9 +171,7 @@ class UserManager(BaseUserManager[UserCreate, UserDB]):
         if not password:
             password = passlib.pwd.genword()
 
-        curr_superuser_res = await self.user_db.collection.find_one(
-            {"is_superuser": True}
-        )
+        curr_superuser_res = await self.get_superuser()
         if curr_superuser_res:
             user = UserDB(**curr_superuser_res)
             update = {"password": password}

backend/btrixcloud/utils.py

@@ -1,6 +1,11 @@
 """ k8s utils """
 
 import os
+import asyncio
+import sys
+import signal
+import atexit
+
 from datetime import datetime
 
 from redis import asyncio as exceptions
@@ -46,3 +51,35 @@ async def get_redis_crawl_stats(redis, crawl_id):
 
     stats = {"found": pages_found, "done": pages_done, "size": archive_size}
     return stats
+
+
+def run_once_lock(name):
+    """run once lock via temp directory
+    - if dir doesn't exist, return true
+    - if exists, return false"""
+    lock_dir = "/tmp/." + name
+    try:
+        os.mkdir(lock_dir)
+    # pylint: disable=bare-except
+    except:
+        return False
+
+    # just in case, delete dir on exit
+    def del_dir():
+        print("release lock: " + lock_dir, flush=True)
+        os.rmdir(lock_dir)
+
+    atexit.register(del_dir)
+    return True
+
+
+def register_exit_handler():
+    """register exit handler to exit on SIGTERM"""
+    loop = asyncio.get_running_loop()
+
+    def exit_handler():
+        """sigterm handler"""
+        print("SIGTERM received, exiting")
+        sys.exit(1)
+
+    loop.add_signal_handler(signal.SIGTERM, exit_handler)

backend/btrixcloud/worker.py

@@ -1,47 +0,0 @@
-"""
-Unique Worker exposed as decorator by_one_worker
-"""
-
-from pathlib import Path
-import os
-from functools import cached_property
-
-
-class UniqueWorker:
-    """Class to run async tasks in single worker only."""
-
-    def __init__(self, path):
-        self.path = Path(path)
-        self.pid = str(os.getpid())
-        self.set_id()
-
-    def set_id(self):
-        """Create path to pid file and write to pid."""
-        if not self.path.exists():
-            self.path.parents[0].mkdir(parents=True, exist_ok=True)
-
-        with open(self.path, "w", encoding="utf-8") as pid_file:
-            pid_file.write(self.pid)
-
-    @cached_property
-    def is_assigned(self):
-        """Check if worker has been assigned to unique worker."""
-        with open(self.path, "r", encoding="utf-8") as pid_file:
-            assigned_worker = pid_file.read()
-
-        return assigned_worker == self.pid
-
-
-def by_one_worker(worker_pid_path):
-    """Decorator which runs function in unique worker."""
-    unique_worker = UniqueWorker(worker_pid_path)
-
-    def deco(pid_path):
-        def wrapped(*args, **kwargs):
-            if not unique_worker.is_assigned:
-                return ""
-            return pid_path(*args, **kwargs)
-
-        return wrapped
-
-    return deco