track

Documentation

Overview

Package track provides a simple interface for tracking known proxies by endpoint/name and correctly handling expiration and exclusivity. The provided Tracker type wraps a workpool.Pool, updating per-key counts as new proxies are discovered and/or old proxies are expired.

Index

• type Config
  • func (c *Config) SetDefaults()
• type Key
• type Lease
• type Tracker
  • func New(ctx context.Context, c Config) *Tracker
  • func (p *Tracker) Acquire() <-chan Lease
  • func (p *Tracker) Start(key Key)
  • func (p *Tracker) Stop(key Key)
  • func (p *Tracker) StopAll()
  • func (p *Tracker) TrackExpected(lease Lease, proxies ...string)
  • func (p *Tracker) WithProxy(work func(), lease Lease, principals ...string) (didWork bool)

Types

type Config

type Config struct {
	// ProxyExpiry is the duration an entry will be held sice the last
	// successful connection to, or message about, a given proxy.
	ProxyExpiry time.Duration
	// TickRate is the rate at which expired entries are cleared from
	// the cache of known proxies.
	TickRate time.Duration
}

Config configures basic Tracker parameters.

func (*Config) SetDefaults

func (c *Config) SetDefaults()

SetDefaults set default values for Config.

type Key

type Key struct {
	Cluster string
	Type    string
	Addr    utils.NetAddr
}

Key uniquely identifies a reversetunnel endpoint.

type Lease

type Lease = workpool.Lease

type Tracker

type Tracker struct {
	Config
	// contains filtered or unexported fields
}

Tracker is a helper for tracking proxies located behind reverse tunnels and triggering agent spawning as needed. Tracker wraps a workpool.Pool instance and manages a cache of proxies which *may* exist. As proxies are discovered, or old proxies expire, the target counts are automatically updated for the associated key in the workpool. Agents can attempt to "claim" exclusivity for a given proxy, ensuring that multiple agents are not run against the same proxy.

func New

func New(ctx context.Context, c Config) *Tracker

New configures a new tracker instance.

func (*Tracker) Acquire

func (p *Tracker) Acquire() <-chan Lease

Acquire grants access to the Acquire channel of the embedded work group.

func (*Tracker) Start

func (p *Tracker) Start(key Key)

Start starts tracking for specified key.

func (*Tracker) Stop

func (p *Tracker) Stop(key Key)

Stop stops tracking for specified key.

func (*Tracker) StopAll

func (p *Tracker) StopAll()

StopAll permanently deactivates this tracker and cleans up all background goroutines.

func (*Tracker) TrackExpected

func (p *Tracker) TrackExpected(lease Lease, proxies ...string)

TrackExpected starts/refreshes tracking for expected proxies. Called by agents when gossip messages are received.

func (*Tracker) WithProxy

func (p *Tracker) WithProxy(work func(), lease Lease, principals ...string) (didWork bool)

WithProxy runs the supplied closure if and only if no other work is currently being done with the proxy identified by principals.