Glossary of Log Service related Terms. More...

Glossary of Log Service related Terms.

Log Service

ASP Service that provides logging facility to various applications / ASP components in the cluster.

Logger

A component using the Log Service to record its events of interest.

Log Record

One unit of information related to an event. This is an ordered set of information. Log Record has two parts - header and user data. Header contains meta-information regarding the event and data part contains the actual information.

Log Stream

It is a conceptual flow of Log Records. Every Log Stream has a theme associated with it, based on which the consumer can decide whether the events of interest are available in this stream on not. Streams have names and scope for addressing.

Local Log Stream

A Log Stream local to one node. This stream is not visible for Logging on any other node in the system. Components running on the same node only can log into this stream. But consumers on any node can consume this Log Stream.

Global Log Stream

A Log Stream visible in the cluster. Any component in the cluster can log into this stream.

Log File

One of the destination for Log Stream and persistent store for Log Records. A collection of Log Streams can flow into one Log File for the ease of management of data.

Log Configuration File

Persistent store for configuration of a Log File.

Log File Unit

A Log File is a logical collection of Log File Units, where one Log File Unit maps to one physical file on disc.

Log Client

Part of the Log Service linked to the Logger and/or Log Stream Handler. This provides Log Service interface to the Logger and Log Stream Handler.

Log Service Element

One process per ASP enabled node in the cluster that provides part of the functionality of the Log Service. All the Log Service Elements along with Log Clients form the Log Service. This element is owner for all the Local Log Streams on its node.

Master Log Service Element

Log Service Element running on the System Controller node. This element is the owner of all the Global Log Streams in the cluster.

Log Stream Handler

An application that has registered its interest in receiving Log Records in real-time mode from the Log Service Element. These records are made available to the Log Stream Handler in push mode. Except the Log File Handler, no other handler is part of Log Service.

Log File Handler

Log File Handler is one type of Log Stream Handler which receives the Log Records from the Log Stream and persist them in the Log File. This is the only handler part of the Log Service.

Log Viewer

Application used for viewing the logged records. This is not part of Log Service. The viewers are of two types - offline viewer and online viewer. Offline viewer interacts with either the Log File Handler or archived files to display Log Records. Online viewer registers itself as a Log Stream Handler and displays the records in real-time.

Archiver

Application used for siphoning off the logged records to some other form of persistent storage. This is not part of Log Service.

Log Reader

Application that programmatically consumes the logged records. Typical readers are application looking for missing Notifications/Events.

Filter

A pattern that controls the logging of records. Only the Log Records matching this pattern are actually logged into the Log Stream.

StreamId

Each stream in the cluster is uniquely identified by a number called stream identifier or streamId. In the LogRecord it identifies the stream to which the record belongs to.

ClientId

Each logging client in the cluster is uniquely identified by a number called client identifier or clientId. In the LogRecord it idetifies the client that has logged this record.