SnowFox core

This repository contains the core SnowFox components.

Component groups

• core.bin: Components for core binaries.
• core.context: Components to store the different execution contexts.
• core.event: Componets that form the base of the event model.
• core.interface: Interfaces are components that define how other components interact among each other and define the overall architecture of the system.
• core.lifecycle: Definitions and helpers for Lifecycle events.
• core.model: Models are components that define individual concepts fixed though SnowFox (daemon, clients, and everything related).
• core.posix: Different posix implementations.
• core.protocol: The definition files for communication portocols.
• core.registry: Components to store registires of different implementations of the interfaces. This is helpful to inject concrete classes without an explicit dependency between components.
• core.utility: Miscellaneous utility components.

Components

Binaries

• core.bin.async-process: Common classes and helpers for event based processes.
• core.bin.client: Command line interface to the server.
• core.bin.daemon: Main SnowFox executable for environment setup and daemon processes orchestration.
• core.bin.manager: Unprivileged process with the logic of the system
• core.bin.spawner: Privileged process for restricted operations on behalf of the Manager process.

Cluster

• core.cluster.node: Represents and manipulates a cluster node.

Contexts

Contexts are a way to do dependency injection. A context is a container for a set of intefraces that are used by the system and are populated at the start with the appropriate instances of concrete interfaces.

• core.context.client: Stores a client specific runtime context.
• core.context.daemon: Stores a daemon specific runtime context.
• core.context.dynamic: Evolving and configurable context for the manager.
• core.context.event: Framework for event correlation runtime contexts.
• core.context.static: Fixed context for all processes.

Events

Some event components are more then a model and always required:

• core.event.client.unix: EventSource that connects to a UNIX socket.
• core.event.drain.fd: EventDrain that writes to a file descriptor.
• core.event.drain.null: EventDrain that writed to /dev/null.
• core.event.source.connected: Socket connection-aware EventSource.
• core.event.source.fd: EventSource that reads from a file descriptor.
• core.event.source.manaual: EventSource that emits manually enqueued events.
• core.event.source.readline: EventSource that reads stdin through GNU readline.
• core.event.source.scheduled: EventSource that emits events sheduled by other components.
• core.event.source.signal: EventSource triggered by process signals.
• core.event.source.unix: EventSource that waits for connections over a UNIX socket.

Interfaces

• core.interface.config: Configuration loaders for nodes, services, etc ...
• core.interface.lifecycle: The lifecycle system implementation.
• core.interface.posix: Interface to Linux posix API.

Lifecycles

• core.lifecycle.client: Client specific lifecycle steps.
• core.lifecycle.event: Event lifecycle helpers and steps.
• core.lifecycle.process: Unix process lifecycle events.

Models

• core.model.cli-parser: Definition of a command line parser.
• core.model.connector: Definition of a Spawner interface to processes.
• core.model.event: Base classes and features that form the event's subsystem. Contains event, source, drain, and manager.
• core.model.logger: Interface for logging events.
• core.model.options: Access generic variables/options.
• core.model.repositoy: The definition of a repository.
• core.model.service: Service definition and state.

Protocols

• core.protocol.manager_spawner: The Manager to Spawner messages.
• core.protocol.daemon_manager: The Daemon to Manager messages.
• core.protocol.daemon_spawner: The Daemon to Spawner messages.
• core.protocol.public: The public protocol for clients to interact with the daemon.
• core.protocol.test: Protocol used for tests.

Registries

• core.registry.base: Generic container for injectable instances.
• core.registry.cli-parser: Regisrty for command line parsers.
• core.registry.event.handler: Registry for protobuf to EventRef factories.
• core.registry.event.managers: Registry for event managers.
• core.registry.event.sources: Registry for event sources.
• core.registry.repositories: Registry of supported configuration repos.

Utilities

• core.utility.daemoniser: Base class for instances that want to daemonise themselves.
• core.utility.forker: Base class for forking into multiple processes.
• core.utility.lua: Wrappert classes for LUA.
• core.utility.process: Process related utility functions.
• core.utility.protobuf: Utilitiy functions to send/receive protocol buffers.
• core.utility.scored-list: Linked lists of elements sorted by score.
• core.utility.status: Store and manipulate status information.
• core.utility.string: String related utilities.

Misc

The following core components do not actually fit in any category:

• core.exceptions: Definitions of exceptions used throughout the SnowFox.
• core.compile-time: A set of templates that are expanded at compile time.

Posix

• core.posix.restricted: Posix implementation used in the Spawner.
• core.posix.user: Posix implementaion used by the Manager.