ntpmonitor

Documentation

Index

• Variables
• func RandomChoice[T any](s []T, n int) []T
• type Config
  • func LoadConfig(path string) (*Config, error)
• type LiveNTPClient
  • func (c LiveNTPClient) QueryWithOptions(srv string, opts ntp.QueryOptions) (*ntp.Response, error)
• type NTPClient
• type NTPMonitor
  • func New(configFile string) (*NTPMonitor, error)
  • func NewFromConfig(cfg *Config) (*NTPMonitor, error)
  • func NewFromConfigWithClient(cfg *Config, client NTPClient) (*NTPMonitor, error)
  • func (n *NTPMonitor) Start()
  • func (n *NTPMonitor) Stop()

Variables

var (
	// ErrInvTime indicates that the local time has drifted too much
	// from the monitored NTP servers.
	ErrInvTime = errors.New("local time differs from observed")
	// ErrTooFewServers means that the number of trusted servers are
	// smaller then the selected num servers to query.
	ErrTooFewServers = errors.New("too few ntp servers configured")
	// ErrNoResponse indicates that there is an error to communicate with
	// the remote NTP servers
	ErrNoResponse = errors.New("no ntp response")
	// ErrThreshold means that there is no positive threshold value
	ErrThreshold = errors.New("no valid server threshold set")
	// ErrDeltaTooSmall is referring to when the max delta time is
	// smaller than the request timeout which can give unstable behaviour.
	ErrDeltaTooSmall = errors.New("delta is too small")
)

Functions

func RandomChoice

func RandomChoice[T any](s []T, n int) []T

RandomChoice returns a random selection of n items from the slice s. The choice is made using a PSEUDO RANDOM selection. If n is greater than len(s), an empty slice is returned.

Types

type Config

type Config struct {
	RequestAttempts int      `yaml:"request_attempts"`
	RequestTimeout  int      `yaml:"request_timeout"`
	NumServers      int      `yaml:"num_servers"`
	MaxTimeDelta    int      `yaml:"max_time_delta"`
	ServerThreshold int      `yaml:"server_threshold"`
	Period          int      `yaml:"period"`
	Servers         []string `yaml:"servers"`
}

Config holds the configuration for a NTPMonitor

func LoadConfig

func LoadConfig(path string) (*Config, error)

LoadConfig reads a yaml file from a provided path, instantiating a new Config object with the vales found. No sanity checking is made of the loaded values.

type LiveNTPClient

type LiveNTPClient struct{}

func (LiveNTPClient) QueryWithOptions

func (c LiveNTPClient) QueryWithOptions(srv string, opts ntp.QueryOptions) (*ntp.Response, error)

type NTPClient

type NTPClient interface {
	QueryWithOptions(srv string, opts ntp.QueryOptions) (*ntp.Response, error)
}

type NTPMonitor

type NTPMonitor struct {
	// contains filtered or unexported fields
}

NTPMonitor compares the local time with a set of trusted NTP servers.

func New

func New(configFile string) (*NTPMonitor, error)

New creates a NTPMonitor, reading the configuration from the provided path.

func NewFromConfig

func NewFromConfig(cfg *Config) (*NTPMonitor, error)

NewFromConfig creates a NTPMonitor from an instantiated configuration.

func NewFromConfigWithClient

func NewFromConfigWithClient(cfg *Config, client NTPClient) (*NTPMonitor, error)

func (*NTPMonitor) Start

func (n *NTPMonitor) Start()

Start the periodic monitor. Once started, it runs until Stop() is called,

func (*NTPMonitor) Stop

func (n *NTPMonitor) Stop()

Stop the monitoring.