frog

package module
v0.2.0 Latest Latest
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 Go to latest Published: Oct 9, 2019 License: MIT Imports: 9 Imported by: 7

README

frog

Overview

Frog is a package for logging output.

When connected to a terminal, Frog allows lines to be fixed to the bottom of the output and updated quickly and efficiently. This allows for display of data that would be surperfluous in a log file, but is really nice to have when watching the output in a terminal.

Frog uses ANSI/VT-100 commands to change colors and move the cursor. Most terminals support these commands, although Windows is a special case. The Windows cmd prompt only supports ANSI in the more recent Windows 10 builds. Older versions of Windows requires a third-party terminal like ConEmu/Cmdr or mintty.

frog demo

Features

  • Multiple logging levels
    • Transient: Data that is safe to ignore (like progress bars and estimated time remaining).
    • Verbose: Data for debugging (disabled most of the time).
    • Info: Normal log lines (usually enabled).
    • Warning: Unusual events.
    • Error: Something went wrong.
    • Fatal: Display this text then halt the entire app.
  • Fixing one or more lines in place
    • Creates a sub-Logger that re-writes Transient log lines.
    • non-Transient lines get sent up to the parent logger for normal processing and display.
  • Optional use of ANSI colors
    • Automatic disabling of ANSI if no terminal detected.
    • If your terminal is a Windows cmd prompt, attempt to enable native ANSI support (recent updates of Windows 10 only).
    • Support NO_COLOR env var to disable colorized output (does not disable all ANSI commands, just ANSI colors).

TODO

  • ✓ Write to two Loggers simultaneously
  • JSON Printer
  • Structured logging
  • Only re-draw the parts of fixed lines that have changed

Documentation

Index

Constants

This section is empty.

Variables

View Source 
var IsNoColorSet = false

Functions

This section is empty.

Types

type Buffered 

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

func NewBuffered 

func NewBuffered(cfg Config, prn Printer) *Buffered

func (*Buffered) AddFixedLine 

func (l *Buffered) AddFixedLine() Logger

AddFixedLine creates a Logger that, when connected to a terminal, draws over itself. Thread safe.

func (*Buffered) Close 

func (l *Buffered) Close()

Close should be called before the app exits, to ensure any buffered output is flushed. Thread safe.

func (*Buffered) Errorf 

func (l *Buffered) Errorf(format string, a ...interface{}) Logger

func (*Buffered) Fatalf 

func (l *Buffered) Fatalf(format string, a ...interface{})

func (*Buffered) Infof 

func (l *Buffered) Infof(format string, a ...interface{}) Logger

func (*Buffered) Logf added in v0.2.0 

func (l *Buffered) Logf(level Level, format string, a ...interface{}) Logger

func (*Buffered) SetMinLevel 

func (l *Buffered) SetMinLevel(level Level) Logger

func (*Buffered) Transientf added in v0.2.0 

func (l *Buffered) Transientf(format string, a ...interface{}) Logger

func (*Buffered) Verbosef 

func (l *Buffered) Verbosef(format string, a ...interface{}) Logger

func (*Buffered) Warningf 

func (l *Buffered) Warningf(format string, a ...interface{}) Logger

type ChildLogger added in v0.2.0 

type ChildLogger interface {
	// Parent returns the parent Logger, or nil if it has no parent.
	Parent() Logger
}

ChildLogger is the interface for loggers that feed back to a parent.

type Config 

type Config struct {
	Writer   io.Writer
	UseAnsi  bool
	UseColor bool
}

type FixedLine 

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

FixedLine is a Logger that attempts to overwrite the same line in the terminal, allowing progress bars and other simple UI for the human to consume.

If the Printer's CanUseAnsi is false, then it simply redirects to the normal behavior of the parent Buffered Logger.

If the Printer's CanUseAnsi is true, then the Transient level is always printed, regardless of the MinLevel. This allows progress bars that do not pollute logs with garbage when not connected to a terminal.

func (*FixedLine) Close 

func (l *FixedLine) Close()

func (*FixedLine) Errorf 

func (l *FixedLine) Errorf(format string, a ...interface{}) Logger

func (*FixedLine) Fatalf 

func (l *FixedLine) Fatalf(format string, a ...interface{})

func (*FixedLine) Infof 

func (l *FixedLine) Infof(format string, a ...interface{}) Logger

func (*FixedLine) Logf added in v0.2.0 

func (l *FixedLine) Logf(level Level, format string, a ...interface{}) Logger

func (*FixedLine) Parent added in v0.2.0 

func (l *FixedLine) Parent() Logger

func (*FixedLine) SetMinLevel 

func (l *FixedLine) SetMinLevel(level Level) Logger

func (*FixedLine) Transientf added in v0.2.0 

func (l *FixedLine) Transientf(format string, a ...interface{}) Logger

func (*FixedLine) Verbosef 

func (l *FixedLine) Verbosef(format string, a ...interface{}) Logger

func (*FixedLine) Warningf 

func (l *FixedLine) Warningf(format string, a ...interface{}) Logger

type FixedLineLogger added in v0.2.0 

type FixedLineLogger interface {
	// AddFixedLine creates a logger that always overwrites the same terminal line,
	// and always writes line level Progress.
	// Returned Logger should have its Close() called before its parent.
	AddFixedLine() Logger
}

FixedLineLogger is the interface for loggers that support fixing a line in place, for progress bars or other transient status messages.

type Level 

type Level byte
const (
	Transient Level = iota // strictly unimportant, ie progress bars, real-time byte counts, estimated time remaining, etc
	Verbose                // debugging info
	Info                   // normal message
	Warning                // something unusual happened
	Error                  // something bad happened
	Fatal                  // stop everything right now

)

type Logger 

type Logger interface {
	// Close ensures any buffers are flushed and any resources released.
	// It is safe to call Close more than once (but consecutive calls do nothing).
	Close()

	// SetMinLevel sets the lowest Level that will be logged.
	SetMinLevel(level Level) Logger

	// Logf is how log lines are added.
	Logf(level Level, format string, a ...interface{}) Logger

	// Transientf et al are just shortcuts for calling Logf with specific levels
	// Note that Fatalf doesn't return itself like the others do because it isn't expected to return at all.
	Transientf(format string, a ...interface{}) Logger
	Verbosef(format string, a ...interface{}) Logger
	Infof(format string, a ...interface{}) Logger
	Warningf(format string, a ...interface{}) Logger
	Errorf(format string, a ...interface{}) Logger
	Fatalf(format string, a ...interface{})
}

func AddFixedLine added in v0.2.0 

func AddFixedLine(log Logger) Logger

AddFixedLine adds a new logger on a fixed line, if supported. Else, returns passed in Logger.

func New 

func New(t NewLogger) Logger

New creates a Buffered logger that writes to os.Stdout, and autodetects any attached Terminal on stdout to decide if ANSI should be used. The caller is responsible for calling Close() before the process ends.

func Parent added in v0.2.0 

func Parent(log Logger) Logger

func ParentOrSelf added in v0.2.0 

func ParentOrSelf(log Logger) Logger

type Msg 

type Msg struct {
	Type  MsgType
	Line  int32
	Level Level
	Msg   string
}

type MsgType 

type MsgType byte
const (
	MsgPrint      MsgType = iota // string to print
	MsgFatal                     // stop processor without closing channel
	MsgAddLine                   // add a fixed line
	MsgRemoveLine                // remove a fixed line
)

type NewLogger added in v0.2.0 

type NewLogger byte
const (
	Auto NewLogger = iota
	Basic
)

type Printer 

type Printer struct {
	PrintTime  bool
	PrintLevel bool
}

func (*Printer) Render 

func (p *Printer) Render(useAnsi bool, useColor bool, level Level, format string, a ...interface{}) string

type TeeLogger added in v0.2.0 

type TeeLogger struct {
	Primary   Logger
	Secondary Logger
}

TeeLogger directs all traffic to both a primary and secondary logger

func (*TeeLogger) AddFixedLine added in v0.2.0 

func (l *TeeLogger) AddFixedLine() Logger

func (*TeeLogger) Close added in v0.2.0 

func (l *TeeLogger) Close()

func (*TeeLogger) Errorf added in v0.2.0 

func (l *TeeLogger) Errorf(format string, a ...interface{}) Logger

func (*TeeLogger) Fatalf added in v0.2.0 

func (l *TeeLogger) Fatalf(format string, a ...interface{})

func (*TeeLogger) Infof added in v0.2.0 

func (l *TeeLogger) Infof(format string, a ...interface{}) Logger

func (*TeeLogger) Logf added in v0.2.0 

func (l *TeeLogger) Logf(level Level, format string, a ...interface{}) Logger

func (*TeeLogger) SetMinLevel added in v0.2.0 

func (l *TeeLogger) SetMinLevel(level Level) Logger

func (*TeeLogger) Transientf added in v0.2.0 

func (l *TeeLogger) Transientf(format string, a ...interface{}) Logger

func (*TeeLogger) Verbosef added in v0.2.0 

func (l *TeeLogger) Verbosef(format string, a ...interface{}) Logger

func (*TeeLogger) Warningf added in v0.2.0 

func (l *TeeLogger) Warningf(format string, a ...interface{}) Logger

type Unbuffered added in v0.2.0 

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

func NewUnbuffered added in v0.2.0 

func NewUnbuffered(w io.Writer, prn Printer) *Unbuffered

func (*Unbuffered) Close added in v0.2.0 

func (l *Unbuffered) Close()

func (*Unbuffered) Errorf added in v0.2.0 

func (l *Unbuffered) Errorf(format string, a ...interface{}) Logger

func (*Unbuffered) Fatalf added in v0.2.0 

func (l *Unbuffered) Fatalf(format string, a ...interface{})

func (*Unbuffered) Infof added in v0.2.0 

func (l *Unbuffered) Infof(format string, a ...interface{}) Logger

func (*Unbuffered) Logf added in v0.2.0 

func (l *Unbuffered) Logf(level Level, format string, a ...interface{}) Logger

func (*Unbuffered) SetMinLevel added in v0.2.0 

func (l *Unbuffered) SetMinLevel(level Level) Logger

func (*Unbuffered) Transientf added in v0.2.0 

func (l *Unbuffered) Transientf(format string, a ...interface{}) Logger

func (*Unbuffered) Verbosef added in v0.2.0 

func (l *Unbuffered) Verbosef(format string, a ...interface{}) Logger

func (*Unbuffered) Warningf added in v0.2.0 

func (l *Unbuffered) Warningf(format string, a ...interface{}) Logger

Source Files

View all Source files

Directories

Path Synopsis
cmd
example command
example2 command

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