From faeb7db953dda6be124987157caf2f78932eb252 Mon Sep 17 00:00:00 2001
From: =?utf8?q?Roland=20H=C3=A4der?= <roland@mxchange.org>
Date: Sat, 3 Jun 2023 07:50:29 +0200
Subject: [PATCH] Continued: - inter-process locking added, prevents nasty
 stuff

---
 fba.py             | 27 +++++++++++++++++++++++++++
 fetch_bkali.py     |  4 +++-
 fetch_blocks.py    |  4 +++-
 fetch_fba_rss.py   |  4 +++-
 fetch_instances.py |  4 +++-
 5 files changed, 39 insertions(+), 4 deletions(-)

diff --git a/fba.py b/fba.py
index 612bc03..c8a088c 100644
--- a/fba.py
+++ b/fba.py
@@ -19,10 +19,13 @@ import hashlib
 import re
 import reqto
 import json
+import os
 import sqlite3
 import sys
+import tempfile
 import time
 import validators
+import zc.lockfile
 
 with open("config.json") as f:
     config = json.loads(f.read())
@@ -143,6 +146,10 @@ patterns = [
     re.compile("^[a-f0-9]{7}$"),
 ]
 
+# Lock file
+lockfile = tempfile.gettempdir() + '/.' + __name__ + '.lock'
+LOCK = None
+
 ##### Cache #####
 
 def is_cache_initialized(key: str) -> bool:
@@ -1544,3 +1551,23 @@ def tidyup(string: str) -> str:
     string = re.sub("(.+)\@", "", string)
 
     return string
+
+def lock_process():
+    global LOCK
+    try:
+        print(f"DEBUG: Acquiring lock: '{lockfile}'")
+        LOCK = zc.lockfile.LockFile(lockfile)
+        print("DEBUG: Lock obtained.")
+
+    except zc.lockfile.LockError:
+        print(f"ERROR: Cannot aquire lock: '{lockfile}'")
+        sys.exit(100)
+
+def shutdown():
+    print("DEBUG: Closing database connection ...")
+    connection.close()
+    print("DEBUG: Releasing lock ...")
+    LOCK.close()
+    print(f"DEBUG: Deleting lockfile='{lockfile}' ...")
+    os.remove(lockfile)
+    print("DEBUG: Shutdown completed.")
diff --git a/fetch_bkali.py b/fetch_bkali.py
index acfe7c6..01aea5a 100755
--- a/fetch_bkali.py
+++ b/fetch_bkali.py
@@ -22,6 +22,8 @@ import sys
 import validators
 import fba
 
+fba.lock_process()
+
 domains = list()
 try:
     fetched = fba.post_json_api("gql.api.bka.li", "/v1/graphql", json.dumps({
@@ -66,4 +68,4 @@ if len(domains) > 0:
         print(f"INFO: Fetching instances from domain='{domain}' ...")
         fba.fetch_instances(domain, None, None, sys.argv[0])
 
-fba.connection.close()
+fba.shutdown()
diff --git a/fetch_blocks.py b/fetch_blocks.py
index 86e5162..b5a49c4 100755
--- a/fetch_blocks.py
+++ b/fetch_blocks.py
@@ -25,6 +25,8 @@ import re
 import validators
 import fba
 
+fba.lock_process()
+
 fba.cursor.execute(
     "SELECT domain, software, origin, nodeinfo_url FROM instances WHERE software IN ('pleroma', 'mastodon', 'friendica', 'misskey', 'gotosocial', 'bookwyrm', 'takahe') AND (last_blocked IS NULL OR last_blocked < ?) ORDER BY rowid DESC", [time.time() - fba.config["recheck_block"]]
 )
@@ -546,4 +548,4 @@ for blocker, software, origin, nodeinfo_url in rows:
 
     blockdict = []
 
-fba.connection.close()
+fba.shutdown()
diff --git a/fetch_fba_rss.py b/fetch_fba_rss.py
index 6745531..7e888e2 100755
--- a/fetch_fba_rss.py
+++ b/fetch_fba_rss.py
@@ -22,6 +22,8 @@ import rss_parser
 import sys
 import fba
 
+fba.lock_process()
+
 feed = sys.argv[1]
 
 domains = list()
@@ -61,4 +63,4 @@ if len(domains) > 0:
         print(f"INFO: Fetching instances from domain='{domain}' ...")
         fba.fetch_instances(domain, None, None, sys.argv[0])
 
-fba.connection.close()
+fba.shutdown()
diff --git a/fetch_instances.py b/fetch_instances.py
index 5dabad0..e20bb75 100755
--- a/fetch_instances.py
+++ b/fetch_instances.py
@@ -24,6 +24,8 @@ import time
 import validators
 import fba
 
+fba.lock_process()
+
 instance = sys.argv[1]
 
 # Initial fetch
@@ -45,4 +47,4 @@ for row in rows:
     print(f"INFO: Fetching instances for instance '{row[0]}' ('{row[2]}') of origin='{row[1]}',nodeinfo_url='{row[3]}'")
     fba.fetch_instances(row[0], row[1], row[2], sys.argv[0], row[3])
 
-fba.connection.close()
+fba.shutdown()
-- 
2.39.5