ext

Documentation

Index

• func EscalateErrHandler(h log.Handler) log.Handler
• func FatalHandler(h log.Handler) log.Handler
• func RandId(idlen int) string
• type HotSwap
  • func HotSwapHandler(h log.Handler) *HotSwap
  • func (h *HotSwap) Log(r *log.Record) error
  • func (h *HotSwap) Swap(newHandler log.Handler)
• type Speculative
  • func SpeculativeHandler(size int, h log.Handler) *Speculative
  • func (h *Speculative) Flush()
  • func (h *Speculative) Log(r *log.Record) error

Functions

func EscalateErrHandler

func EscalateErrHandler(h log.Handler) log.Handler

EscalateErrHandler wraps another handler and passes all records through unchanged except if the logged context contains a non-nil error value in its context. In that case, the record's level is raised to LvlError unless it was already more serious (LvlCrit).

This allows you to log the result of all functions for debugging and still capture error conditions when in production with a single log line. As an example, the following the log record will be written out only if there was an error writing a value to redis:

logger := logext.EscalateErrHandler(
    log.LvlFilterHandler(log.LvlInfo, log.StdoutHandler))

reply, err := redisConn.Do("SET", "foo", "bar")
logger.Debug("Wrote value to redis", "reply", reply, "err", err)
if err != nil {
    return err
}

func FatalHandler

func FatalHandler(h log.Handler) log.Handler

FatalHandler makes critical errors exit the program immediately, much like the log.Fatal* methods from the standard log package

func RandId

func RandId(idlen int) string

RandId creates a random identifier of the requested length. Useful for assigning mostly-unique identifiers for logging and identification that are unlikely to collide because of short lifespan or low set cardinality

Types

type HotSwap

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

func HotSwapHandler

func HotSwapHandler(h log.Handler) *HotSwap

HotSwapHandler wraps another handler that may swapped out dynamically at runtime in a thread-safe fashion. HotSwapHandler is the same functionality used to implement the SetHandler method for the default implementation of Logger.

func (*HotSwap) Log

func (h *HotSwap) Log(r *log.Record) error

func (*HotSwap) Swap

func (h *HotSwap) Swap(newHandler log.Handler)

type Speculative

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

func SpeculativeHandler

func SpeculativeHandler(size int, h log.Handler) *Speculative

SpeculativeHandler is a handler for speculative logging. It keeps a ring buffer of the given size full of the last events logged into it. When Flush is called, all buffered log records are written to the wrapped handler. This is extremely for continuosly capturing debug level output, but only flushing those log records if an exceptional condition is encountered.

func (*Speculative) Flush

func (h *Speculative) Flush()

func (*Speculative) Log

func (h *Speculative) Log(r *log.Record) error