Proyecto LCX Dispatcharr multicuenta

dispatcharr/persistent_lock.py

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+# dispatcharr/persistent_lock.py
+import uuid
+import redis
+
+class PersistentLock:
+    """
+    A persistent, auto-expiring lock that uses Redis.
+
+    Usage:
+      1. Instantiate with a Redis client, a unique lock key (e.g. "lock:account:123"),
+         and an optional timeout (in seconds).
+      2. Call acquire() to try to obtain the lock.
+      3. Optionally, periodically call refresh() to extend the lock's lifetime.
+      4. When finished, call release() to free the lock.
+    """
+    def __init__(self, redis_client: redis.Redis, lock_key: str, lock_timeout: int = 120):
+        """
+        Initialize the lock.
+
+        :param redis_client: An instance of redis.Redis.
+        :param lock_key: The unique key for the lock.
+        :param lock_timeout: Time-to-live for the lock in seconds.
+        """
+        self.redis_client = redis_client
+        self.lock_key = lock_key
+        self.lock_timeout = lock_timeout
+        self.lock_token = None
+        self.has_lock = False
+
+    def has_lock(self) -> bool:
+        return self.has_lock
+
+    def acquire(self) -> bool:
+        """
+        Attempt to acquire the lock. Returns True if successful.
+        """
+        self.lock_token = str(uuid.uuid4())
+        # Set the lock with NX (only if not exists) and EX (expire time)
+        result = self.redis_client.set(self.lock_key, self.lock_token, nx=True, ex=self.lock_timeout)
+        if result is not None:
+            self.has_lock = True
+
+        return result is not None
+
+    def refresh(self) -> bool:
+        """
+        Refresh the lock's expiration time if this instance owns the lock.
+        Returns True if the expiration was successfully extended.
+        """
+        current_value = self.redis_client.get(self.lock_key)
+        if current_value and current_value == self.lock_token:
+            self.redis_client.expire(self.lock_key, self.lock_timeout)
+            self.has_lock = False
+            return True
+        return False
+
+    def release(self) -> bool:
+        """
+        Release the lock only if owned by this instance.
+        Returns True if the lock was successfully released.
+        """
+        # Use a Lua script for atomicity: only delete if the token matches.
+        lua_script = """
+        if redis.call("get", KEYS[1]) == ARGV[1] then
+            return redis.call("del", KEYS[1])
+        else
+            return 0
+        end
+        """
+        release_lock = self.redis_client.register_script(lua_script)
+        result = release_lock(keys=[self.lock_key], args=[self.lock_token])
+        return result == 1
+
+# Example usage (for testing purposes only):
+if __name__ == "__main__":
+    import os
+    import sys
+    # Connect to Redis using environment variables; adjust connection parameters as needed.
+    redis_host = os.environ.get("REDIS_HOST", "localhost")
+    redis_port = int(os.environ.get("REDIS_PORT", 6379))
+    redis_db = int(os.environ.get("REDIS_DB", 0))
+    redis_password = os.environ.get("REDIS_PASSWORD", "")
+    redis_user = os.environ.get("REDIS_USER", "")
+    ssl_kwargs = {}
+    if os.environ.get("REDIS_SSL", "false").lower() == "true":
+        import ssl as _ssl
+        ssl_kwargs["ssl"] = True
+        ssl_kwargs["ssl_cert_reqs"] = (
+            _ssl.CERT_REQUIRED if os.environ.get("REDIS_SSL_VERIFY", "true").lower() == "true"
+            else _ssl.CERT_NONE
+        )
+        for env_var, key in [
+            ("REDIS_SSL_CA_CERT", "ssl_ca_certs"),
+            ("REDIS_SSL_CERT", "ssl_certfile"),
+            ("REDIS_SSL_KEY", "ssl_keyfile"),
+        ]:
+            path = os.environ.get(env_var, "")
+            if path:
+                if not os.path.isfile(path):
+                    print(f"Redis TLS: {env_var}={path!r} — file not found.")
+                    sys.exit(1)
+                ssl_kwargs[key] = path
+
+    client = redis.Redis(
+        host=redis_host,
+        port=redis_port,
+        db=redis_db,
+        password=redis_password if redis_password else None,
+        username=redis_user if redis_user else None,
+        **ssl_kwargs
+    )
+    lock = PersistentLock(client, "lock:example_account", lock_timeout=120)
+
+    if lock.acquire():
+        print("Lock acquired successfully!")
+        # Do work here...
+        # Optionally refresh the lock periodically:
+        if lock.refresh():
+            print("Lock refreshed.")
+        # Finally, release the lock:
+        if lock.release():
+            print("Lock released.")
+        else:
+            print("Failed to release lock.")
+    else:
+        print("Failed to acquire lock.")