LogDog Coordinator

The LogDog Coordinator is an AppEngine application that serves as a central coordinating and interactive authority for a LogDog instance. The Coordinator is responsible for:

• Supplying logs to end users through its logs API.
• Coordinating log stream state throughout its lifecycle.
• Handling Butler Prefix registration.
• Acting as a configuration authority for its deployment.
• Accepting stream registrations from Collector instances.
• Dispatching archival tasks to Archivist instances.

Modules

A Coordinator occupies the AppEngine space of a given cloud project, and assumes ownership of that project's resources. It is composed of several cooperative AppEngine modules.

Default

The default module exposes the Logs API for log stream querying and consumption.

It is currently an AppEngine Managed VM, since Managed VMs are the only type of AppEngine instance that can use gRPC, and gRPC is needed to read from BigTable.

Services

The services module exposes management endpoints to the instance's microservices, notably the Collector and Archivist microservices. These endpoints are used to coordinate the microservice-managed aspects of the log stream lifecycle.

Backend

The backend module hosts the Tumble journaled processing service, which handles log stream lifecycle transitions and deadlines.

Static

The static module hosts static content, including:

• The LogDog Web Application
• The LogDog Lightweight Stream Viewer
• rpcexplorer