forked from stretchr/tracer
/
tracer.go
256 lines (198 loc) · 6.4 KB
/
tracer.go
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package tracer
import (
"fmt"
"github.com/stretchr/stew/strings"
"time"
)
// deferredTrace holds the format string and args sent for deferred processing
type deferredTrace struct {
fmt string
args []interface{}
level Level
now time.Time
}
// Trace is a type that contains an actual trace
type Trace struct {
// data stores the trace string
Data string
// level stores the level of this trace
Level Level
// timestamp stores the time at which this trace occurred
TimeStamp time.Time
}
// tracer is a type providing trace capabilities to a go application
type Tracer struct {
// data stores the individual string entries in the tracer
data []Trace
// level determines what level a trace must be to actually be logged
level Level
// deferred holds whether processing is deferred or now
deferred bool
// deferredData holds the deferredTrace for the traces to be processed
deferredData []deferredTrace
}
type Level int
const (
// LevelEverything defines a trace level that is guarenteed to trace everything. This trace level
// should never be passed to the Trace command.
LevelEverything Level = iota
// LevelDebug defines a trace level that should be used for verbose tracing.
LevelDebug
// LevelInfo defines a trace level that should be used for normal activity tracing.
LevelInfo
// LevelWarning defines a trace level that should be used for tracing warnings.
LevelWarning
// LevelError defines a trace level that should be used for error tracing.
LevelError
// LevelCritical defines a trace level that should be used for critical error tracing.
LevelCritical
// LevelNothing defines a trace level that is guarenteed to trace nothing. This trace level
// should never be passed to the Trace command.
LevelNothing
)
// New creates a new tracer
//
// The level argument is used to filter the trace to the desired level of detail.
// For example, a trace level of LevelEverything will log everything, where a trace level of LevelWarning
// will log only warnings, errors and criticals.
func New(level Level) *Tracer {
tracer := new(Tracer)
tracer.level = level
tracer.data = make([]Trace, 0, 100)
return tracer
}
// NewDeferred creates a new tracer that defers processing until Process() is called
//
// The level argument is used to filter the trace to the desired level of detail.
// For example, a trace level of LevelEverything will log everything, where a trace level of LevelWarning
// will log only warnings, errors and criticals.
func NewDeferred(level Level) *Tracer {
tracer := new(Tracer)
tracer.level = level
tracer.data = make([]Trace, 0, 100)
tracer.deferred = true
tracer.deferredData = make([]deferredTrace, 0, 100)
return tracer
}
// Level gets the current level of this Tracer.
func (t *Tracer) Level() Level {
if t == nil {
return LevelNothing
}
return t.level
}
// Should gets whether the tracer should trace at the specified level.
func (t *Tracer) Should(level Level) bool {
return t.Level() <= level
}
// Trace saves a piece of trace data at the current time.
func (t *Tracer) Trace(level Level, format string, args ...interface{}) {
if t == nil {
return
}
if level >= t.level && level < LevelNothing {
if t.deferred {
t.deferredData = append(t.deferredData, deferredTrace{fmt: format, args: args, level: level, now: time.Now()})
} else {
trace := Trace{fmt.Sprintf(format, args...), level, time.Now()}
t.data = append(t.data, trace)
}
} else if level <= LevelEverything {
panic("tracer: level is invalid: Cannot Trace with LevelEverything or below.")
} else if level >= LevelNothing {
panic("tracer: level is invalid: Cannot Trace with LevelNothing or above.")
}
}
// TraceDebug is a helper method for tracing at the LevelDebug level
func (t *Tracer) TraceDebug(format string, args ...interface{}) {
t.Trace(LevelDebug, format, args...)
}
// TraceInfo is a helper method for tracing at the LevelInfo level
func (t *Tracer) TraceInfo(format string, args ...interface{}) {
t.Trace(LevelInfo, format, args...)
}
// TraceWarning is a helper method for tracing at the LevelWarning level
func (t *Tracer) TraceWarning(format string, args ...interface{}) {
t.Trace(LevelWarning, format, args...)
}
// TraceError is a helper method for tracing at the LevelError level
func (t *Tracer) TraceError(format string, args ...interface{}) {
t.Trace(LevelError, format, args...)
}
// TraceCritical is a helper method for tracing at the LevelCritical level
func (t *Tracer) TraceCritical(format string, args ...interface{}) {
t.Trace(LevelCritical, format, args...)
}
// Returns a copy of the trace data
func (t *Tracer) Data() []Trace {
if t == nil {
return nil
}
copiedTraces := make([]Trace, len(t.data))
copy(copiedTraces, t.data)
return copiedTraces
}
//Process processes deferred traces
func (t *Tracer) Process() {
if t.deferred && len(t.deferredData) > 0 {
for _, defTrace := range t.deferredData {
trace := Trace{fmt.Sprintf(defTrace.fmt, defTrace.args...), defTrace.level, defTrace.now}
t.data = append(t.data, trace)
}
t.deferredData = make([]deferredTrace, 0, 100)
}
}
// Returns a copy of the trace data as an array of string
func (t *Tracer) StringData() []string {
if t == nil {
return nil
}
t.Process()
stringTraces := make([]string, 0, len(t.data))
for _, trace := range t.data {
stringTraces = append(stringTraces, fmt.Sprintf("TRACE: %s\t%s\t\t%s", trace.TimeStamp.String(), LevelToString(trace.Level), trace.Data))
}
return stringTraces
}
// String gets a nicely formatted string of the trace data.
func (t *Tracer) String() string {
if t == nil {
return ""
}
t.Process()
return strings.MergeStrings("\n", strings.JoinStrings("\n", t.StringData()...))
}
// Returns a copy of the trace data, filtered by trace level
func (t *Tracer) Filter(level Level) []Trace {
if t == nil {
return nil
}
t.Process()
filteredTraces := make([]Trace, 0, len(t.data))
for _, trace := range t.data {
if trace.Level == level {
filteredTraces = append(filteredTraces, trace)
}
}
return filteredTraces
}
// Returns a string representation of the level
func LevelToString(level Level) string {
switch level {
case LevelEverything:
return "LevelEverything"
case LevelDebug:
return " LevelDebug"
case LevelInfo:
return " LevelInfo"
case LevelWarning:
return " LevelWarning"
case LevelError:
return " LevelError"
case LevelCritical:
return " LevelCritical"
case LevelNothing:
return " LevelNothing"
}
return ""
}