Search network node events Leave feedback

This page contains information about the purpose and use of all search network events. The events are available through the events property of the SearchNetworkNode class, which returns an instance of the NodeEventHub class.

A handler is a function, a lambda or another callable that takes two arguments: the sender and the event arguments. Subscribe a handler with +=, for example node.events.indexing_completed += on_indexing_completed; -= removes the subscription, and clear() removes all the handlers of the event, for example node.events.indexing_completed.clear(). Most node events are raised on engine worker threads, several of them at the same time, so a handler that collects data must protect it, for example with a threading.Lock.

The configuration_completed event occurs when the search network configuration process is finished. It is raised on an engine worker thread and can arrive just after configure_all_nodes returns, so a script that ends right after that call may not see it.

The indexing_completed event occurs when indexing of all enqueued documents is finished.

The extraction_completed event occurs when the extraction of all enqueued documents started by the extract method is finished. See the Indexing documents page.

The deletion_completed event occurs when all enqueued deletions of documents are finished.

The optimization_completed event occurs when optimization of all nodes is finished.

The synchronization_completed event occurs when synchronization with all nodes is finished.

The attribute_changes_completed event occurs when all enqueued attribute changes are finished.

The status_changed event occurs when the search network status changes.

The data_extracted event occurs when the data have been extracted from a document. The extracted data are available through the data property of the event arguments.

The document_indexed event occurs when a document has been indexed.

The document_deleted event occurs when a document has been deleted.

The error_occurred event of a node occurs when an error occurs on this node. The event arguments contain the indexes of the node and the service where the error occurred. The errors of all nodes are also written to the logger of the master node.

The indexing_progress_changed event occurs when the progress of the indexing operation has changed.

The optimization_progress_changed event occurs when the progress of the optimization operation has changed.

The examples on this page use the master node of a running search network. The following code creates and starts the master node as described on the Search network deployment page; the slave nodes must be started beforehand. The examples that follow continue this code in the same Python process.

from groupdocs.search.common import FileLogger
from groupdocs.search.scaling import SearchNetworkNode
from groupdocs.search.scaling.configuring import Configuration, TcpSettings

base_path = "./SearchNetwork/"
base_port = 49100

# Loading the search network configuration from a file
configuration = Configuration.load(base_path + "Configuration.xml")

# Creating, configuring and starting the master node; the timeouts are specified in milliseconds
node = SearchNetworkNode.create_master_node(
    0,
    base_path + "Node0",
    TcpSettings(base_port, 3000, 3000, 3000, 1000),
    FileLogger(base_path + "Log.txt", 4.0),
    configuration)
node.configure_all_nodes()
node.start()

The following code example, which continues the previous one, demonstrates subscribing to the search network events. The handlers print their messages when the operations described on the next pages of this section run, for example, indexing, deleting or optimizing.

node.events.indexing_completed += lambda sender, args: print("Indexing complete")
node.events.extraction_completed += lambda sender, args: print("Extraction complete")
node.events.deletion_completed += lambda sender, args: print("Deleting complete")
node.events.optimization_completed += lambda sender, args: print("Optimization complete")
node.events.synchronization_completed += lambda sender, args: print("Synchronization complete")
node.events.attribute_changes_completed += lambda sender, args: print("Attribute changes complete")
node.events.status_changed += lambda sender, args: print(
    "Status changed: %s -> %s" % (args.old_status.name, args.new_status.name))
node.events.data_extracted += lambda sender, args: print(
    "Data extracted (%d): %s" % (args.extractor_index, args.document_key))
node.events.document_indexed += lambda sender, args: print(
    "Document indexed (%d): %s" % (args.shard_index, args.document_key))
node.events.document_deleted += lambda sender, args: print(
    "Document deleted (%d): %s" % (args.shard_index, args.document_key))
node.events.error_occurred += lambda sender, args: print(
    "Error occurred (%d, %d): %s" % (args.node_index, args.service_index, args.message))
node.events.indexing_progress_changed += lambda sender, args: print(
    "Indexing progress changed (%d, %d): %s" % (args.node_index, args.service_index, args.progress_percentage))
node.events.optimization_progress_changed += lambda sender, args: print(
    "Optimization progress changed (%d, %d): %s" % (args.node_index, args.service_index, args.progress_percentage))

You may easily run the code from documentation articles and see the features in action in our GitHub examples:

• GroupDocs.Search for Python via .NET examples

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