logtracr

README

Logtracr: a go-logr flight recorder backend

This package implements a log flight recorder backend compatible with the logr interface. Please check the design document for more details

The package is used mostly in conjunction Kubernetes' klog in the kubernetes ecosystem, but is meant to be generic and working with any logr-based solution.

What is a log flight recorder

Let's borrow a great concise description from the go blog:

Suppose you work on a web service and an RPC took a very long time.
You couldn’t start tracing at the point you knew the RPC was already taking a while, because the root cause of the slow request already happened and wasn’t recorded.
[...]
The insight with flight recording is to have tracing on continuously and always keep the most recent trace data around, just in case.
Then, once something interesting happens, the program can just write out whatever it has!

This package wants to offer the same functionality but for logs, to enable (better) review, auditing, support of the program decisions.

Maturity

This is a ALPHA grade implementation.

LICENSE

Apache v2

Documentation

Index

• Constants
• func DefaultBackend() *log.Logger
• func GetLogIDKey() string
• func New(std stdr.StdLogger, lc *TracrMap, verbose int, opts stdr.Options) logr.Logger
• func RunForever(ctx context.Context, logger logr.Logger, interval time.Duration, ...)
• func SetLogIDKey(val string)
• func SetupWithEnv(ctx context.Context, backend *log.Logger) (logr.Logger, logr.Logger, error)
• func SetupWithParams(ctx context.Context, backend *log.Logger, params Params) (logr.Logger, logr.Logger)
• type Config
  • func ConfigFromEnv() (Config, error)
• type EnvVarMissing
  • func (ev *EnvVarMissing) Error() string
• type Params
• type SpanBlob
  • func (ln *SpanBlob) IsExpired(now time.Time, delta time.Duration) bool
• type TimeFunc
• type TracrMap
  • func NewTracrMap(timeFunc TimeFunc) *TracrMap
  • func (lc *TracrMap) Get(logID string) (string, bool)
  • func (lc *TracrMap) Len() int
  • func (lc *TracrMap) PopExpired(now time.Time, delta time.Duration) []*SpanBlob
  • func (lc *TracrMap) Put(logID, data string) error
• type UnsupportedSetting
  • func (us *UnsupportedSetting) Error() string

Constants

const (
	LogTracrDirEnvVar      string = "LOGTRACR_DUMP_DIR"
	LogTracrIntervalEnvVar string = "LOGTRACR_DUMP_INTERVAL"
	LogTracrVerboseEnvVar  string = "LOGTRACR_VERBOSE"
)

Functions

func DefaultBackend

func DefaultBackend() *log.Logger

func GetLogIDKey

func GetLogIDKey() string

func New

func New(std stdr.StdLogger, lc *TracrMap, verbose int, opts stdr.Options) logr.Logger

func RunForever

func RunForever(ctx context.Context, logger logr.Logger, interval time.Duration, baseDirectory string, lc *TracrMap)

func SetLogIDKey

func SetLogIDKey(val string)

func SetupWithEnv

func SetupWithEnv(ctx context.Context, backend *log.Logger) (logr.Logger, logr.Logger, error)

func SetupWithParams

func SetupWithParams(ctx context.Context, backend *log.Logger, params Params) (logr.Logger, logr.Logger)

Types

type Config

type Config struct {
	Verbose       int           `json:"verbose"`
	DumpInterval  time.Duration `json:"dumpInterval"`
	DumpDirectory string        `json:"dumpDirectory"`
}

func ConfigFromEnv

func ConfigFromEnv() (Config, error)

type EnvVarMissing

type EnvVarMissing struct {
	Name string
}

func (*EnvVarMissing) Error

func (ev *EnvVarMissing) Error() string

type Params

type Params struct {
	Conf        Config
	MainSink    *logr.Logger // optional, use nil to let the package use its defaults
	Timestamper TimeFunc
}

type SpanBlob

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

func (*SpanBlob) IsExpired

func (ln *SpanBlob) IsExpired(now time.Time, delta time.Duration) bool

type TimeFunc

type TimeFunc func() time.Time

type TracrMap

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

func NewTracrMap

func NewTracrMap(timeFunc TimeFunc) *TracrMap

func (*TracrMap) Get

func (lc *TracrMap) Get(logID string) (string, bool)

Get is (mostly) meant for testing purposes

func (*TracrMap) Len

func (lc *TracrMap) Len() int

Len is (mostly) meant for testing purposes

func (*TracrMap) PopExpired

func (lc *TracrMap) PopExpired(now time.Time, delta time.Duration) []*SpanBlob

func (*TracrMap) Put

func (lc *TracrMap) Put(logID, data string) error

type UnsupportedSetting

type UnsupportedSetting struct {
	Name  string
	Value string
}

func (*UnsupportedSetting) Error

func (us *UnsupportedSetting) Error() string