open-consul/vendor/github.com/hashicorp/go-hclog/logger.go

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package hclog
import (
"io"
"log"
"os"
"strings"
)
var (
//DefaultOutput is used as the default log output.
DefaultOutput io.Writer = os.Stderr
// DefaultLevel is used as the default log level.
DefaultLevel = Info
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)
// Level represents a log level.
type Level int32
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const (
// NoLevel is a special level used to indicate that no level has been
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// set and allow for a default to be used.
NoLevel Level = 0
// Trace is the most verbose level. Intended to be used for the tracing
// of actions in code, such as function enters/exits, etc.
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Trace Level = 1
// Debug information for programmer lowlevel analysis.
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Debug Level = 2
// Info information about steady state operations.
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Info Level = 3
// Warn information about rare but handled events.
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Warn Level = 4
// Error information about unrecoverable events.
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Error Level = 5
)
// Format is a simple convience type for when formatting is required. When
// processing a value of this type, the logger automatically treats the first
// argument as a Printf formatting string and passes the rest as the values
// to be formatted. For example: L.Info(Fmt{"%d beans/day", beans}).
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type Format []interface{}
// Fmt returns a Format type. This is a convience function for creating a Format
// type.
func Fmt(str string, args ...interface{}) Format {
return append(Format{str}, args...)
}
// A simple shortcut to format numbers in hex when displayed with the normal
// text output. For example: L.Info("header value", Hex(17))
type Hex int
// A simple shortcut to format numbers in octal when displayed with the normal
// text output. For example: L.Info("perms", Octal(17))
type Octal int
// A simple shortcut to format numbers in binary when displayed with the normal
// text output. For example: L.Info("bits", Binary(17))
type Binary int
// ColorOption expresses how the output should be colored, if at all.
type ColorOption uint8
const (
// ColorOff is the default coloration, and does not
// inject color codes into the io.Writer.
ColorOff ColorOption = iota
// AutoColor checks if the io.Writer is a tty,
// and if so enables coloring.
AutoColor
// ForceColor will enable coloring, regardless of whether
// the io.Writer is a tty or not.
ForceColor
)
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// LevelFromString returns a Level type for the named log level, or "NoLevel" if
// the level string is invalid. This facilitates setting the log level via
// config or environment variable by name in a predictable way.
func LevelFromString(levelStr string) Level {
// We don't care about case. Accept both "INFO" and "info".
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levelStr = strings.ToLower(strings.TrimSpace(levelStr))
switch levelStr {
case "trace":
return Trace
case "debug":
return Debug
case "info":
return Info
case "warn":
return Warn
case "error":
return Error
default:
return NoLevel
}
}
func (l Level) String() string {
switch l {
case Trace:
return "trace"
case Debug:
return "debug"
case Info:
return "info"
case Warn:
return "warn"
case Error:
return "error"
case NoLevel:
return "none"
default:
return "unknown"
}
}
// Logger describes the interface that must be implemeted by all loggers.
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type Logger interface {
// Args are alternating key, val pairs
// keys must be strings
// vals can be any type, but display is implementation specific
// Emit a message and key/value pairs at a provided log level
Log(level Level, msg string, args ...interface{})
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// Emit a message and key/value pairs at the TRACE level
Trace(msg string, args ...interface{})
// Emit a message and key/value pairs at the DEBUG level
Debug(msg string, args ...interface{})
// Emit a message and key/value pairs at the INFO level
Info(msg string, args ...interface{})
// Emit a message and key/value pairs at the WARN level
Warn(msg string, args ...interface{})
// Emit a message and key/value pairs at the ERROR level
Error(msg string, args ...interface{})
// Indicate if TRACE logs would be emitted. This and the other Is* guards
// are used to elide expensive logging code based on the current level.
IsTrace() bool
// Indicate if DEBUG logs would be emitted. This and the other Is* guards
IsDebug() bool
// Indicate if INFO logs would be emitted. This and the other Is* guards
IsInfo() bool
// Indicate if WARN logs would be emitted. This and the other Is* guards
IsWarn() bool
// Indicate if ERROR logs would be emitted. This and the other Is* guards
IsError() bool
// ImpliedArgs returns With key/value pairs
ImpliedArgs() []interface{}
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// Creates a sublogger that will always have the given key/value pairs
With(args ...interface{}) Logger
// Returns the Name of the logger
Name() string
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// Create a logger that will prepend the name string on the front of all messages.
// If the logger already has a name, the new value will be appended to the current
// name. That way, a major subsystem can use this to decorate all it's own logs
// without losing context.
Named(name string) Logger
// Create a logger that will prepend the name string on the front of all messages.
// This sets the name of the logger to the value directly, unlike Named which honor
// the current name as well.
ResetNamed(name string) Logger
// Updates the level. This should affect all sub-loggers as well. If an
// implementation cannot update the level on the fly, it should no-op.
SetLevel(level Level)
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// Return a value that conforms to the stdlib log.Logger interface
StandardLogger(opts *StandardLoggerOptions) *log.Logger
// Return a value that conforms to io.Writer, which can be passed into log.SetOutput()
StandardWriter(opts *StandardLoggerOptions) io.Writer
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}
// StandardLoggerOptions can be used to configure a new standard logger.
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type StandardLoggerOptions struct {
// Indicate that some minimal parsing should be done on strings to try
// and detect their level and re-emit them.
// This supports the strings like [ERROR], [ERR] [TRACE], [WARN], [INFO],
// [DEBUG] and strip it off before reapplying it.
InferLevels bool
// ForceLevel is used to force all output from the standard logger to be at
// the specified level. Similar to InferLevels, this will strip any level
// prefix contained in the logged string before applying the forced level.
// If set, this override InferLevels.
ForceLevel Level
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}
// LoggerOptions can be used to configure a new logger.
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type LoggerOptions struct {
// Name of the subsystem to prefix logs with
Name string
// The threshold for the logger. Anything less severe is supressed
Level Level
// Where to write the logs to. Defaults to os.Stderr if nil
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Output io.Writer
// An optional Locker in case Output is shared. This can be a sync.Mutex or
// a NoopLocker if the caller wants control over output, e.g. for batching
// log lines.
Mutex Locker
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// Control if the output should be in JSON.
JSONFormat bool
// Include file and line information in each log line
IncludeLocation bool
// The time format to use instead of the default
TimeFormat string
// Control whether or not to display the time at all. This is required
// because setting TimeFormat to empty assumes the default format.
DisableTime bool
// Color the output. On Windows, colored logs are only avaiable for io.Writers that
// are concretely instances of *os.File.
Color ColorOption
// A function which is called with the log information and if it returns true the value
// should not be logged.
// This is useful when interacting with a system that you wish to suppress the log
// message for (because it's too noisy, etc)
Exclude func(level Level, msg string, args ...interface{}) bool
}
// InterceptLogger describes the interface for using a logger
// that can register different output sinks.
// This is useful for sending lower level log messages
// to a different output while keeping the root logger
// at a higher one.
type InterceptLogger interface {
// Logger is the root logger for an InterceptLogger
Logger
// RegisterSink adds a SinkAdapter to the InterceptLogger
RegisterSink(sink SinkAdapter)
// DeregisterSink removes a SinkAdapter from the InterceptLogger
DeregisterSink(sink SinkAdapter)
// Create a interceptlogger that will prepend the name string on the front of all messages.
// If the logger already has a name, the new value will be appended to the current
// name. That way, a major subsystem can use this to decorate all it's own logs
// without losing context.
NamedIntercept(name string) InterceptLogger
// Create a interceptlogger that will prepend the name string on the front of all messages.
// This sets the name of the logger to the value directly, unlike Named which honor
// the current name as well.
ResetNamedIntercept(name string) InterceptLogger
// Return a value that conforms to the stdlib log.Logger interface
StandardLoggerIntercept(opts *StandardLoggerOptions) *log.Logger
// Return a value that conforms to io.Writer, which can be passed into log.SetOutput()
StandardWriterIntercept(opts *StandardLoggerOptions) io.Writer
}
// SinkAdapter describes the interface that must be implemented
// in order to Register a new sink to an InterceptLogger
type SinkAdapter interface {
Accept(name string, level Level, msg string, args ...interface{})
}
// Flushable represents a method for flushing an output buffer. It can be used
// if Resetting the log to use a new output, in order to flush the writes to
// the existing output beforehand.
type Flushable interface {
Flush() error
}
// OutputResettable provides ways to swap the output in use at runtime
type OutputResettable interface {
// ResetOutput swaps the current output writer with the one given in the
// opts. Color options given in opts will be used for the new output.
ResetOutput(opts *LoggerOptions) error
// ResetOutputWithFlush swaps the current output writer with the one given
// in the opts, first calling Flush on the given Flushable. Color options
// given in opts will be used for the new output.
ResetOutputWithFlush(opts *LoggerOptions, flushable Flushable) error
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}
// Locker is used for locking output. If not set when creating a logger, a
// sync.Mutex will be used internally.
type Locker interface {
// Lock is called when the output is going to be changed or written to
Lock()
// Unlock is called when the operation that called Lock() completes
Unlock()
}
// NoopLocker implements locker but does nothing. This is useful if the client
// wants tight control over locking, in order to provide grouping of log
// entries or other functionality.
type NoopLocker struct{}
// Lock does nothing
func (n NoopLocker) Lock() {}
// Unlock does nothing
func (n NoopLocker) Unlock() {}
var _ Locker = (*NoopLocker)(nil)