log

package
v1.5.4 Latest Latest
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Published: Jan 16, 2017 License: MIT Imports: 11 Imported by: 41

Documentation

Overview

Package log provides a structured, levelled logger interface for use in server handlers, which handles multiple output streams. A typical use might be to log everything to stderr, but to add another logger to send important data off to The Default logger simply logs to stderr, a local File logger is available, and data can be extracted and sent elsewhere by additional loggers (for example page hits to a stats service).

Usage: logger,err := log.NewStdErr() log.Add(logger) log.Error(log.V{"key":value,"key":value})

Index

Constants

View Source
const (
	// Separator is used to separate key:value pairs
	Separator = ":"
	// PrefixDate constant for date prefixes
	PrefixDate = "2006-01-02 "
	// PrefixTime  constants for time prefix
	PrefixTime = "15:04:05 "
	// PrefixDateTime  constants for date + time prefix
	PrefixDateTime = "2006-01-02:15:04:05 "
)
View Source
const (
	// FileFlags serts the flags for OpenFile on the log file
	FileFlags = os.O_WRONLY | os.O_APPEND | os.O_CREATE

	// FilePermissions serts the perms for OpenFile on the log file
	FilePermissions = 0640
)
View Source
const (
	// LevelKey is the key for setting level
	LevelKey = "level"
	// MessageKey is the key for a message
	MessageKey = "msg"
	// DurationKey is used by the Time function
	DurationKey = "duration"
	// ErrorKey is used for errors
	ErrorKey = "error"
	// IPKey is used for IP addresses (for colouring)
	IPKey = "ip"
	// URLKey is used for identifying URLs (for filtering)
	URLKey = "url"
	// TraceKey is used for trace ids emitted in middleware
	TraceKey = "trace"
)
View Source
const (
	LevelNone = iota
	LevelDebug
	LevelInfo
	LevelError
	LevelFatal
)

Valid levels for logging.

Variables

View Source
var (
	// LevelNames is a list of human-readable for levels.
	LevelNames = []string{"none", "debug", "info", "error", "fatal"}

	// NoColor determines if a terminal is colourable or not
	NoColor = os.Getenv("TERM") == "dumb"

	// LevelColors is a list of human-friendly terminal colors for levels.
	LevelColors = []string{"\033[0m", "\033[34m", "\033[32m", "\033[33m", "\033[31m"}

	// TraceColor sets a for IP addresses or request id
	TraceColor = "\033[33m"

	// ClearColors clears all formatting
	ClearColors = "\033[0m"
)

Functions

func Add added in v1.5.2

func Add(l StructuredLogger)

Add adds the given logger to the list of outputs, it should not be called from other goroutines.

func Debug added in v1.5.2

func Debug(values map[string]interface{})

Debug sends the key/value map at level Debug to all registered (log)gers.

func Error added in v1.5.2

func Error(values map[string]interface{})

Error sends the key/value map at level Error to all registered loggers.

func Fatal added in v1.5.2

func Fatal(values map[string]interface{})

Fatal sends the key/value map at level Fatal to all registered loggers, no other action is taken.

func Info added in v1.5.2

func Info(values map[string]interface{})

Info sends the key/value map at level Info to all registered loggers.

func Log added in v1.5.2

func Log(values map[string]interface{})

Log sends the key/value map to all registered loggers. If level is not set, it defaults to LevelInfo.

func Middleware added in v1.5.2

func Middleware(h http.HandlerFunc) http.HandlerFunc

Middleware adds a logging wrapper and request tracing to requests.

func SetRequestID added in v1.5.2

func SetRequestID(r *http.Request, rid *RequestID) *http.Request

SetRequestID saves the request id in the request context.

func Time added in v1.5.2

func Time(start time.Time, values map[string]interface{})

Time sends the key/value map to all registered loggers with an additional duration, start and end params set.

func Trace added in v1.5.2

func Trace(r *http.Request) string

Trace retreives the request id from a request as a string.

Types

type Default added in v1.5.2

type Default struct {

	// Prefix is used to prefix any log lines emitted.
	Prefix string

	// Level is the level above which input is ignored.
	Level int

	// Writer is the output of this logger.
	Writer io.Writer

	// Color sets whether terminal colour instructions are emitted.
	Color bool
}

Default defines a default logger which simply logs to Writer, Writer is set to stderr, Level is LevelDebug and Prefix is empty by default.

func NewStdErr added in v1.5.2

func NewStdErr(prefix string) (*Default, error)

NewStdErr returns a new StructuredLogger of type Default which writes to stderr. By default prefix is empty, and level is LevelDebug (the lowest), so all output is captured.

func (*Default) LevelColor added in v1.5.2

func (d *Default) LevelColor(l int) string

LevelColor returns the human-readable colour for this level.

func (*Default) LevelName added in v1.5.2

func (d *Default) LevelName(l int) string

LevelName returns the human-readable name for this level.

func (*Default) LevelValue added in v1.5.2

func (d *Default) LevelValue(values V) int

LevelValue extracts the Level from values (if present) or returns 0 if not.

func (*Default) Log added in v1.5.2

func (d *Default) Log(values V)

Log logs the key:value pairs given to the writer. Keys are sorted before output in alphabetical order to ensure consistent results.

func (*Default) SortedKeys added in v1.5.2

func (d *Default) SortedKeys(values V) []string

SortedKeys returns an array of keys for a map sorted in alpha order, this means we get a predictable order for the map entries when we print. The special keys level and message are ommitted.

func (*Default) WriteString added in v1.5.2

func (d *Default) WriteString(s string)

WriteString writes the string to the Writer.

type File added in v1.5.2

type File struct {
	Default // File embeds default
	Path    string
}

File logs to a local file for all messages at or above Level.

func NewFile added in v1.5.2

func NewFile(path string) (*File, error)

NewFile creates a new file logger for the given path at Level Info.

type Logger

type Logger struct {
	Filter string
	// contains filtered or unexported fields
}

Logger conforms with the server.Logger interface

func New

func New(path string, production bool) *Logger

New creates a new Logger which writes to a file and to stderr

func (*Logger) Printf

func (l *Logger) Printf(format string, args ...interface{})

Printf logs events selectively given our filter

type RequestID added in v1.5.2

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

RequestID is but a simple token for tracing requests.

func GetRequestID added in v1.5.2

func GetRequestID(r *http.Request) *RequestID

GetRequestID retreives the request id from a request.

func (*RequestID) String added in v1.5.2

func (r *RequestID) String() string

String returns a string formatting for the request id.

type StructuredLogger added in v1.5.2

type StructuredLogger interface {
	Log(V)
}

StructuredLogger defines an interface for loggers which may be added with Add() to the list of outputs.

type V added in v1.5.2

type V map[string]interface{}

V is a shorthand for values

type Values added in v1.5.2

type Values map[string]interface{}

Values is a map of structured key value pairs usage: log.Warn(log.Values{"user":1,"foo":"bar"})

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