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package hclog
import (
"io"
"log"
"os"
"strings"
"sync"
)
var (
DefaultOutput = os.Stderr
DefaultLevel = Info
)
type Level int32
const (
// This is a special level used to indicate that no level has been
// set and allow for a default to be used.
NoLevel Level = 0
// The most verbose level. Intended to be used for the tracing of actions
// in code, such as function enters/exits, etc.
Trace Level = 1
// For programmer lowlevel analysis.
Debug Level = 2
// For information about steady state operations.
Info Level = 3
// For information about rare but handled events.
Warn Level = 4
// For information about unrecoverable events.
Error Level = 5
)
// 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}). This is a simple
// convience type for when formatting is required.
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...)
}
// 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 "INFO" or "info"
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
}
}
// The main Logger interface. All code should code against this interface only.
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 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
// Creates a sublogger that will always have the given key/value pairs
With(args ...interface{}) Logger
// 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)
// Return a value that conforms to the stdlib log.Logger interface
StandardLogger(opts *StandardLoggerOptions) *log.Logger
}
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
}
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
Output io.Writer
// An optional mutex pointer in case Output is shared
Mutex *sync.Mutex
// 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
}
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