v1.8.1

FIXED:
* Whoops, bit premature on 1.8.0; broke some Linux logging.

bitmask/bitmask.go

@@ -2,8 +2,8 @@ package bitmask
 
 import (
 	"bytes"
-	"errors"
 	"encoding/binary"
+	"errors"
 	"math/bits"
 )
 
@@ -56,7 +56,7 @@ func (m *MaskBit) AddFlag(flag MaskBit) {
 // ClearFlag removes MaskBit flag from m.
 func (m *MaskBit) ClearFlag(flag MaskBit) {
 
-	*m &= flag
+	*m &^= flag
 
 	return
 }
@@ -109,6 +109,15 @@ func (m *MaskBit) Bytes(trim bool) (b []byte) {
 	return
 }
 
+// Copy returns a pointer to a (new) copy of a MaskBit.
+func (m *MaskBit) Copy() (newM *MaskBit) {
+
+	newM = new(MaskBit)
+	*newM = *m
+
+	return
+}
+
 // Value returns the current raw uint value of a MaskBit.
 func (m *MaskBit) Value() (v uint) {
 

logging/TODO

@@ -1,11 +1,22 @@
+- macOS support beyond the legacy NIX stuff. it apparently uses something called "ULS", "Unified Logging System".
+-- https://developer.apple.com/documentation/os/logging
+-- https://developer.apple.com/documentation/os/generating-log-messages-from-your-code
+-- no native Go support (yet)?
+--- https://developer.apple.com/forums/thread/773369
+
 - Implement code line/func/etc. (only for debug?):
   https://stackoverflow.com/a/24809646
   https://golang.org/pkg/runtime/#Caller
   -- log.LlongFile and log.Lshortfile flags don't currently work properly for StdLogger/FileLogger; they refer to the file in logging package rather than the caller.
 
+- StdLogger2; where stdout and stderr are both logged to depending on severity level.
+  - make configurable via OR bitmask
+
 - Suport remote loggers? (eventlog, syslog, systemd)
 
 - JSON logger? YAML logger? XML logger?
 
 - DOCS.
 -- Done, but flesh out.
+
+- Implement io.Writer interfaces

logging/consts.go

@@ -12,3 +12,16 @@ const (
 	// appendFlags are the flags used for testing the file (and opening/writing).
 	appendFlags int = os.O_APPEND | os.O_CREATE | os.O_WRONLY
 )
+
+const PriorityNone logPrio = 0
+const (
+	PriorityEmergency logPrio = 1 << iota
+	PriorityAlert
+	PriorityCritical
+	PriorityError
+	PriorityWarning
+	PriorityNotice
+	PriorityInformational
+	PriorityDebug
+)
+const PriorityAll logPrio = PriorityEmergency | PriorityAlert | PriorityCritical | PriorityError | PriorityWarning | PriorityNotice | PriorityInformational | PriorityDebug

logging/consts_darwin.go

@@ -0,0 +1,9 @@
+package logging
+
+var (
+	// defLogPaths indicates default log paths.
+	defLogPaths = []string{
+		"/var/log/golang/program.log",
+		"~/Library/Logs/Golang/program.log",
+	}
+)

logging/consts_linux.go

@@ -1,32 +1,5 @@
 package logging
 
-import (
-	`log/syslog`
-
-	`r00t2.io/goutils/bitmask`
-)
-
-const (
-	// devlog is the path to the syslog char device.
-	devlog string = "/dev/log"
-	// syslogFacility is the facility to use; it's a little like a context or scope if you think of it in those terms.
-	syslogFacility syslog.Priority = syslog.LOG_USER
-)
-
-// Flags for logger configuration. These are used internally.
-const (
-	// LogUndefined indicates an undefined Logger type.
-	LogUndefined bitmask.MaskBit = 1 << iota
-	// LogJournald flags a SystemDLogger Logger type.
-	LogJournald
-	// LogSyslog flags a SyslogLogger Logger type.
-	LogSyslog
-	// LogFile flags a FileLogger Logger type.
-	LogFile
-	// LogStdout flags a StdLogger Logger type.
-	LogStdout
-)
-
 var (
 	// defLogPaths indicates default log paths.
 	defLogPaths = []string{

logging/consts_nix.go

@@ -0,0 +1,34 @@
+//go:build !(windows || plan9 || wasip1 || js || ios)
+// +build !windows,!plan9,!wasip1,!js,!ios
+
+// I mean maybe it works for plan9 and ios, I don't know.
+
+package logging
+
+import (
+	"log/syslog"
+
+	"r00t2.io/goutils/bitmask"
+)
+
+const (
+	// devlog is the path to the syslog char device.
+	devlog string = "/dev/log"
+	// syslogFacility is the facility to use; it's a little like a context or scope if you think of it in those terms.
+	syslogFacility syslog.Priority = syslog.LOG_USER
+)
+
+// Flags for logger configuration. These are used internally.
+
+// LogUndefined indicates an undefined Logger type.
+const LogUndefined bitmask.MaskBit = iota
+const (
+	// LogJournald flags a SystemDLogger Logger type.
+	LogJournald = 1 << iota
+	// LogSyslog flags a SyslogLogger Logger type.
+	LogSyslog
+	// LogFile flags a FileLogger Logger type.
+	LogFile
+	// LogStdout flags a StdLogger Logger type.
+	LogStdout
+)

logging/doc.go

@@ -3,18 +3,19 @@ Package logging implements and presents various loggers under a unified interfac
 
 These particular loggers (logging.Logger) available are:
 
+	NullLogger
 	StdLogger
 	FileLogger
 	SystemDLogger (Linux only)
-		SyslogLogger (Linux only)
+	SyslogLogger (Linux/macOS/other *NIX-like only)
 	WinLogger (Windows only)
 
-There is a sixth type of logging.Logger, MultiLogger, that allows for multiple loggers to be written to with a single call.
+There is a seventh type of logging.Logger, MultiLogger, that allows for multiple loggers to be written to with a single call.
+As you may have guessed, NullLogger doesn't actually log anything but is fully "functional" as a logging.Logger.
 
 Note that for some Loggers, the prefix may be modified - "literal" loggers (StdLogger and FileLogger) will append a space to the end of the prefix.
 If this is undesired (unlikely), you will need to modify (Logger).Prefix and run (Logger).Logger.SetPrefix(yourPrefixHere) for the respective logger.
 
-
 Every logging.Logger type has the following methods that correspond to certain "levels".
 
 	Alert(s string, v ...interface{}) (err error)
@@ -36,6 +37,7 @@ Note that in the case of a MultiLogger, err (if not nil) will be a (r00t2.io/gou
 logging.Logger types also have the following methods:
 
 	DoDebug(d bool) (err error)
+	GetDebug() (d bool)
 	SetPrefix(p string) (err error)
 	GetPrefix() (p string, err error)
 	Setup() (err error)

logging/errs_linux.go

@@ -1,18 +1,10 @@
 package logging
 
 import (
-	`errors`
-	`fmt`
+	"errors"
 )
 
 var (
 	// ErrNoSysD indicates that the user attempted to add a SystemDLogger to a MultiLogger but systemd is unavailable.
 	ErrNoSysD error = errors.New("a systemd (journald) Logger was requested but systemd is unavailable on this system")
-	// ErrNoSyslog indicates that the user attempted to add a SyslogLogger to a MultiLogger but syslog's logger device is unavailable.
-	ErrNoSyslog error = errors.New("a Syslog Logger was requested but Syslog is unavailable on this system")
-	/*
-		ErrInvalidDevLog indicates that the user attempted to add a SyslogLogger to a MultiLogger but
-		the Syslog char device file is... not actually a char device file.
-	*/
-	ErrInvalidDevLog error = errors.New(fmt.Sprintf("a Syslog Logger was requested but %v is not a valid logger handle", devlog))
 )

logging/errs_nix.go

@@ -0,0 +1,19 @@
+//go:build !(windows || plan9 || wasip1 || js || ios)
+// +build !windows,!plan9,!wasip1,!js,!ios
+
+package logging
+
+import (
+	"errors"
+	"fmt"
+)
+
+var (
+	// ErrNoSyslog indicates that the user attempted to add a SyslogLogger to a MultiLogger but syslog's logger device is unavailable.
+	ErrNoSyslog error = errors.New("a Syslog Logger was requested but Syslog is unavailable on this system")
+	/*
+		ErrInvalidDevLog indicates that the user attempted to add a SyslogLogger to a MultiLogger but
+		the Syslog char device file is... not actually a char device file.
+	*/
+	ErrInvalidDevLog error = errors.New(fmt.Sprintf("a Syslog Logger was requested but %v is not a valid logger handle", devlog))
+)

logging/funcs_file.go

@@ -1,12 +1,12 @@
 package logging
 
 import (
-	`errors`
+	"errors"
 	"fmt"
-	`io/fs`
+	"io/fs"
 	"log"
 	"os"
-	`strings`
+	"strings"
 )
 
 // Setup sets up/configures a FileLogger and prepares it for use.
@@ -65,6 +65,14 @@ func (l *FileLogger) DoDebug(d bool) (err error) {
 	return
 }
 
+// GetDebug returns the debug status of this FileLogger.
+func (l *FileLogger) GetDebug() (d bool) {
+
+	d = l.EnableDebug
+
+	return
+}
+
 /*
 SetPrefix sets the prefix for this FileLogger.
 err will always be nil; it's there for interface-compat.
@@ -212,6 +220,14 @@ func (l *FileLogger) Warning(s string, v ...interface{}) (err error) {
 	return
 }
 
+// ToLogger returns a stdlib log.Logger.
+func (l *FileLogger) ToLogger(prio logPrio) (stdLibLog *log.Logger) {
+
+	stdLibLog = log.New(&logWriter{backend: l, prio: prio}, "", 0)
+
+	return
+}
+
 // renderWrite prepares/formats a log message to be written to this FileLogger.
 func (l *FileLogger) renderWrite(msg, prio string) {
 

logging/funcs_logprio.go

@@ -0,0 +1,23 @@
+package logging
+
+import (
+	`r00t2.io/goutils/bitmask`
+)
+
+// HasFlag provides a wrapper for functionality to the underlying bitmask.MaskBit.
+func (l *logPrio) HasFlag(prio logPrio) (hasFlag bool) {
+
+	var m *bitmask.MaskBit
+	var p *bitmask.MaskBit
+
+	if l == nil {
+		return
+	}
+
+	m = bitmask.NewMaskBitExplicit(uint(*l))
+	p = bitmask.NewMaskBitExplicit(uint(prio))
+
+	hasFlag = m.HasFlag(*p)
+
+	return
+}

logging/funcs_logwriter.go

@@ -0,0 +1,74 @@
+package logging
+
+import (
+	`r00t2.io/goutils/multierr`
+)
+
+// Write writes bytes b to the underlying Logger's priority level if the logWriter's priority level(s) match.
+func (l *logWriter) Write(b []byte) (n int, err error) {
+
+	var s string
+	var mErr *multierr.MultiError = multierr.NewMultiError(nil)
+
+	if b == nil {
+		return
+	}
+
+	s = string(b)
+
+	if l.prio.HasFlag(PriorityEmergency) {
+		if err = l.backend.Emerg(s); err != nil {
+			mErr.AddError(err)
+			err = nil
+		}
+	}
+	if l.prio.HasFlag(PriorityAlert) {
+		if err = l.backend.Alert(s); err != nil {
+			mErr.AddError(err)
+			err = nil
+		}
+	}
+	if l.prio.HasFlag(PriorityCritical) {
+		if err = l.backend.Crit(s); err != nil {
+			mErr.AddError(err)
+			err = nil
+		}
+	}
+	if l.prio.HasFlag(PriorityError) {
+		if err = l.backend.Err(s); err != nil {
+			mErr.AddError(err)
+			err = nil
+		}
+	}
+	if l.prio.HasFlag(PriorityWarning) {
+		if err = l.backend.Warning(s); err != nil {
+			mErr.AddError(err)
+			err = nil
+		}
+	}
+	if l.prio.HasFlag(PriorityNotice) {
+		if err = l.backend.Notice(s); err != nil {
+			mErr.AddError(err)
+			err = nil
+		}
+	}
+	if l.prio.HasFlag(PriorityInformational) {
+		if err = l.backend.Info(s); err != nil {
+			mErr.AddError(err)
+			err = nil
+		}
+	}
+	if l.prio.HasFlag(PriorityDebug) {
+		if err = l.backend.Debug(s); err != nil {
+			mErr.AddError(err)
+			err = nil
+		}
+	}
+
+	if !mErr.IsEmpty() {
+		err = mErr
+		return
+	}
+
+	return
+}

logging/funcs_multilogger.go

@@ -1,11 +1,12 @@
 package logging
 
 import (
-	`errors`
-	`fmt`
-	`sync`
+	"errors"
+	"fmt"
+	`log`
+	"sync"
 
-	`r00t2.io/goutils/multierr`
+	"r00t2.io/goutils/multierr"
 )
 
 // Setup sets up/configures a MultiLogger (and all its MultiLogger.Loggers) and prepares it for use.
@@ -114,6 +115,14 @@ func (m *MultiLogger) DoDebug(d bool) (err error) {
 	return
 }
 
+// GetDebug returns the debug status of this MultiLogger.
+func (m *MultiLogger) GetDebug() (d bool) {
+
+	d = m.EnableDebug
+
+	return
+}
+
 /*
 SetPrefix sets the prefix for this MultiLogger (and all its MultiLogger.Loggers).
 
@@ -362,3 +371,11 @@ func (m *MultiLogger) Warning(s string, v ...interface{}) (err error) {
 
 	return
 }
+
+// ToLogger returns a stdlib log.Logger.
+func (m *MultiLogger) ToLogger(prio logPrio) (stdLibLog *log.Logger) {
+
+	stdLibLog = log.New(&logWriter{backend: m, prio: prio}, "", 0)
+
+	return
+}

logging/funcs_multilogger_mgr.go

@@ -1,10 +1,10 @@
 package logging
 
 import (
-	`path`
+	"path"
 
-	`github.com/google/uuid`
-	`r00t2.io/sysutils/paths`
+	"github.com/google/uuid"
+	"r00t2.io/sysutils/paths"
 )
 
 /*
@@ -145,6 +145,40 @@ func (m *MultiLogger) AddFileLogger(identifier string, logFlags int, logfilePath
 	return
 }
 
+/*
+	AddNullLogger adds a NullLogger to a MultiLogger.
+
+	identifier is a string to use to identify the added NullLogger in MultiLogger.Loggers.
+	If empty, one will be automatically generated.
+*/
+func (m *MultiLogger) AddNullLogger(identifier string) (err error) {
+
+	var exists bool
+	var prefix string
+
+	if identifier == "" {
+		identifier = uuid.New().String()
+	}
+
+	if _, exists = m.Loggers[identifier]; exists {
+		err = ErrExistingLogger
+		return
+	}
+
+	m.Loggers[identifier] = &NullLogger{}
+	if err = m.Loggers[identifier].Setup(); err != nil {
+		return
+	}
+
+	if prefix, err = m.Loggers[identifier].GetPrefix(); err != nil {
+		return
+	}
+
+	m.Loggers[identifier].Debug("logger initialized of type %T with prefix %v", m.Loggers[identifier], prefix)
+
+	return
+}
+
 // RemoveLogger will let you remove a Logger from MultiLogger.Loggers.
 func (m *MultiLogger) RemoveLogger(identifier string) (err error) {
 

logging/funcs_multilogger_mgr_linux.go

@@ -1,11 +1,8 @@
 package logging
 
 import (
-	`os`
-
-	sysd `github.com/coreos/go-systemd/journal`
-	`github.com/google/uuid`
-	`r00t2.io/sysutils/paths`
+	sysd "github.com/coreos/go-systemd/journal"
+	"github.com/google/uuid"
 )
 
 /*
@@ -80,55 +77,3 @@ func (m *MultiLogger) AddSysdLogger(identifier string) (err error) {
 
 	return
 }
-
-/*
-	AddSyslogLogger adds a SyslogLogger to a MultiLogger.
-
-	identifier is a string to use to identify the added SyslogLogger in MultiLogger.Loggers.
-	If empty, one will be automatically generated.
-*/
-func (m *MultiLogger) AddSyslogLogger(identifier string) (err error) {
-
-	var exists bool
-	var hasSyslog bool
-	var stat os.FileInfo
-	var devlogPath string = devlog
-	var prefix string
-
-	if identifier == "" {
-		identifier = uuid.New().String()
-	}
-
-	if _, exists = m.Loggers[identifier]; exists {
-		err = ErrExistingLogger
-		return
-	}
-
-	if hasSyslog, stat, err = paths.RealPathExistsStat(&devlogPath); hasSyslog && err != nil {
-		return
-	} else if !hasSyslog {
-		err = ErrNoSyslog
-		return
-	}
-
-	if stat.Mode().IsRegular() {
-		err = ErrInvalidDevLog
-		return
-	}
-
-	m.Loggers[identifier] = &SyslogLogger{
-		EnableDebug: m.EnableDebug,
-		Prefix:      m.Prefix,
-	}
-	if err = m.Loggers[identifier].Setup(); err != nil {
-		return
-	}
-
-	if prefix, err = m.Loggers[identifier].GetPrefix(); err != nil {
-		return
-	}
-
-	m.Loggers[identifier].Debug("logger initialized of type %T with prefix %v", m.Loggers[identifier], prefix)
-
-	return
-}

logging/funcs_multilogger_mgr_nix.go

@@ -0,0 +1,63 @@
+//go:build !(windows || plan9 || wasip1 || js || ios)
+// +build !windows,!plan9,!wasip1,!js,!ios
+
+package logging
+
+import (
+	"os"
+
+	"github.com/google/uuid"
+	"r00t2.io/sysutils/paths"
+)
+
+/*
+AddSyslogLogger adds a SyslogLogger to a MultiLogger.
+
+identifier is a string to use to identify the added SyslogLogger in MultiLogger.Loggers.
+If empty, one will be automatically generated.
+*/
+func (m *MultiLogger) AddSyslogLogger(identifier string) (err error) {
+
+	var exists bool
+	var hasSyslog bool
+	var stat os.FileInfo
+	var devlogPath string = devlog
+	var prefix string
+
+	if identifier == "" {
+		identifier = uuid.New().String()
+	}
+
+	if _, exists = m.Loggers[identifier]; exists {
+		err = ErrExistingLogger
+		return
+	}
+
+	if hasSyslog, stat, err = paths.RealPathExistsStat(&devlogPath); hasSyslog && err != nil {
+		return
+	} else if !hasSyslog {
+		err = ErrNoSyslog
+		return
+	}
+
+	if stat.Mode().IsRegular() {
+		err = ErrInvalidDevLog
+		return
+	}
+
+	m.Loggers[identifier] = &SyslogLogger{
+		EnableDebug: m.EnableDebug,
+		Prefix:      m.Prefix,
+	}
+	if err = m.Loggers[identifier].Setup(); err != nil {
+		return
+	}
+
+	if prefix, err = m.Loggers[identifier].GetPrefix(); err != nil {
+		return
+	}
+
+	m.Loggers[identifier].Debug("logger initialized of type %T with prefix %v", m.Loggers[identifier], prefix)
+
+	return
+}

logging/funcs_multilogger_mgr_oldnix.go

@@ -0,0 +1,41 @@
+//go:build !(windows || plan9 || wasip1 || js || ios || linux)
+// +build !windows,!plan9,!wasip1,!js,!ios,!linux
+
+// Linux is excluded because it has its own.
+
+package logging
+
+import (
+	"github.com/google/uuid"
+)
+
+/*
+AddDefaultLogger adds a default Logger (as would be determined by GetLogger) to a MultiLogger.
+
+identifier is a string to use to identify the added Logger in MultiLogger.Loggers.
+If empty, one will be automatically generated.
+
+See the documentation for GetLogger for details on other arguments.
+*/
+func (m *MultiLogger) AddDefaultLogger(identifier string, logFlags int, logPaths ...string) (err error) {
+
+	var l Logger
+	var exists bool
+
+	if identifier == "" {
+		identifier = uuid.New().String()
+	}
+
+	if _, exists = m.Loggers[identifier]; exists {
+		err = ErrExistingLogger
+		return
+	}
+
+	if l, err = GetLogger(m.EnableDebug, m.Prefix, logFlags, logPaths...); err != nil {
+		return
+	}
+
+	m.Loggers[identifier] = l
+
+	return
+}

logging/funcs_nulllogger.go

@@ -0,0 +1,86 @@
+package logging
+
+import (
+	`log`
+)
+
+// Setup does nothing at all; it's here for interface compat. 🙃
+func (l *NullLogger) Setup() (err error) {
+	return
+}
+
+// DoDebug does nothing at all; it's here for interface compat. 🙃
+func (l *NullLogger) DoDebug(d bool) (err error) {
+	return
+}
+
+// GetDebug returns the debug status of this NullLogger. It will always return true. 🙃
+func (n *NullLogger) GetDebug() (d bool) {
+
+	d = true
+
+	return
+}
+
+// SetPrefix does nothing at all; it's here for interface compat. 🙃
+func (l *NullLogger) SetPrefix(p string) (err error) {
+	return
+}
+
+// GetPrefix does nothing at all; it's here for interface compat. 🙃
+func (l *NullLogger) GetPrefix() (p string, err error) {
+	return
+}
+
+// Shutdown does nothing at all; it's here for interface compat. 🙃
+func (l *NullLogger) Shutdown() (err error) {
+	return
+}
+
+// Alert does nothing at all; it's here for interface compat. 🙃
+func (l *NullLogger) Alert(s string, v ...interface{}) (err error) {
+	return
+}
+
+// Crit does nothing at all; it's here for interface compat. 🙃
+func (l *NullLogger) Crit(s string, v ...interface{}) (err error) {
+	return
+}
+
+// Debug does nothing at all; it's here for interface compat. 🙃
+func (l *NullLogger) Debug(s string, v ...interface{}) (err error) {
+	return
+}
+
+// Emerg does nothing at all; it's here for interface compat. 🙃
+func (l *NullLogger) Emerg(s string, v ...interface{}) (err error) {
+	return
+}
+
+// Err does nothing at all; it's here for interface compat. 🙃
+func (l *NullLogger) Err(s string, v ...interface{}) (err error) {
+	return
+}
+
+// Info does nothing at all; it's here for interface compat. 🙃
+func (l *NullLogger) Info(s string, v ...interface{}) (err error) {
+	return
+}
+
+// Notice does nothing at all; it's here for interface compat. 🙃
+func (l *NullLogger) Notice(s string, v ...interface{}) (err error) {
+	return
+}
+
+// Warning does nothing at all; it's here for interface compat. 🙃
+func (l *NullLogger) Warning(s string, v ...interface{}) (err error) {
+	return
+}
+
+// ToLogger returns a stdlib log.Logger (that doesn't actually write to anything).
+func (l *NullLogger) ToLogger(prio logPrio) (stdLibLog *log.Logger) {
+
+	stdLibLog = log.New(&nullWriter{}, "", 0)
+
+	return
+}

logging/funcs_nullwriter.go

@@ -0,0 +1,12 @@
+package logging
+
+// nulLWriter writes... nothing. To avoid errors, however, in downstream code it pretends it does (n will *always* == len(b)).
+func (nw *nullWriter) Write(b []byte) (n int, err error) {
+
+	if b == nil {
+		return
+	}
+	n = len(b)
+
+	return
+}

logging/funcs_oldnix.go

@@ -0,0 +1,138 @@
+//go:build !(windows || plan9 || wasip1 || js || ios || linux)
+// +build !windows,!plan9,!wasip1,!js,!ios,!linux
+
+// Linux is excluded because it has its own.
+
+package logging
+
+import (
+	native "log"
+	"os"
+	"path"
+
+	"r00t2.io/goutils/bitmask"
+	"r00t2.io/sysutils/paths"
+)
+
+var (
+	_ = native.Logger{}
+	_ = os.Interrupt
+)
+
+/*
+GetLogger returns an instance of Logger that best suits your system's capabilities.
+
+If enableDebug is true, debug messages (which according to your program may or may not contain sensitive data) are rendered and written.
+
+If prefix is "\x00" (a null byte), then the default logging prefix will be used. If anything else, even an empty string,
+is specified then that will be used instead for the prefix.
+
+logConfigFlags is the corresponding flag(s) OR'd for StdLogger.LogFlags / FileLogger.StdLogger.LogFlags if either is selected. See StdLogger.LogFlags and
+https://pkg.go.dev/log#pkg-constants for details.
+
+logPaths is an (optional) list of strings to use as paths to test for writing. If the file can be created/written to,
+it will be used (assuming you have no higher-level loggers available). Only the first logPaths entry that "works" will be used, later entries will be ignored.
+If you want to log to multiple files simultaneously, use a MultiLogger instead.
+
+If you call GetLogger, you will only get a single ("best") logger your system supports.
+If you want to log to multiple Logger destinations at once (or want to log to an explicit Logger type),
+use GetMultiLogger.
+*/
+func GetLogger(enableDebug bool, prefix string, logConfigFlags int, logPaths ...string) (logger Logger, err error) {
+
+	var logPath string
+	var logFlags bitmask.MaskBit
+	var currentPrefix string
+
+	// Configure system-supported logger(s).
+
+	// If we can detect syslog, use that. If not, try to use a file logger (+ stdout).
+	// Last ditch, stdout.
+	var hasSyslog bool
+	var stat os.FileInfo
+	var devlogPath string = devlog
+
+	if hasSyslog, stat, err = paths.RealPathExistsStat(&devlogPath); hasSyslog && err != nil {
+		return
+	}
+
+	if hasSyslog && !stat.Mode().IsRegular() {
+		logFlags.AddFlag(LogSyslog)
+	} else {
+		var exists bool
+		var success bool
+		var ckLogPaths []string
+
+		logFlags.AddFlag(LogStdout)
+		ckLogPaths = defLogPaths
+		if logPaths != nil {
+			ckLogPaths = logPaths
+		}
+		for _, p := range ckLogPaths {
+			if exists, _ = paths.RealPathExists(&p); exists {
+				if success, err = testOpen(p); err != nil {
+					continue
+				} else if !success {
+					continue
+				}
+				logFlags.AddFlag(LogFile)
+				logPath = p
+				break
+			} else {
+				dirPath := path.Dir(p)
+				if err = paths.MakeDirIfNotExist(dirPath); err != nil {
+					continue
+				}
+				if success, err = testOpen(p); err != nil {
+					continue
+				} else if !success {
+					continue
+				}
+				logFlags.AddFlag(LogFile)
+				logPath = p
+				break
+			}
+		}
+	}
+
+	if logFlags.HasFlag(LogSyslog) {
+		logger = &SyslogLogger{
+			Prefix:      logPrefix,
+			EnableDebug: enableDebug,
+		}
+	} else {
+		if logFlags.HasFlag(LogFile) {
+			logger = &FileLogger{
+				StdLogger: StdLogger{
+					Prefix:      logPrefix,
+					EnableDebug: enableDebug,
+					LogFlags:    logConfigFlags,
+				},
+				Path: logPath,
+			}
+		} else {
+			logger = &StdLogger{
+				Prefix:      logPrefix,
+				EnableDebug: enableDebug,
+				LogFlags:    logConfigFlags,
+			}
+		}
+	}
+
+	if prefix != "\x00" {
+		if err = logger.SetPrefix(prefix); err != nil {
+			return
+		}
+	}
+	if err = logger.Setup(); err != nil {
+		return
+	}
+
+	if currentPrefix, err = logger.GetPrefix(); err != nil {
+		return
+	}
+
+	logger.Debug("logger initialized of type %T with prefix %v", logger, currentPrefix)
+
+	return
+}

logging/funcs_std.go

@@ -2,10 +2,10 @@ package logging
 
 import (
 	"fmt"
-	`io`
-	`log`
-	`os`
-	`strings`
+	"io"
+	"log"
+	"os"
+	"strings"
 )
 
 /*
@@ -80,6 +80,14 @@ func (l *StdLogger) DoDebug(d bool) (err error) {
 	return
 }
 
+// GetDebug returns the debug status of this StdLogger.
+func (l *StdLogger) GetDebug() (d bool) {
+
+	d = l.EnableDebug
+
+	return
+}
+
 /*
 SetPrefix sets the prefix for this StdLogger.
 err will always be nil; it's there for interface-compat.
@@ -236,3 +244,11 @@ func (l *StdLogger) renderWrite(msg, prio string) {
 
 	return
 }
+
+// ToLogger returns a stdlib log.Logger.
+func (l *StdLogger) ToLogger(prio logPrio) (stdLibLog *log.Logger) {
+
+	stdLibLog = log.New(&logWriter{backend: l, prio: prio}, "", 0)
+
+	return
+}

logging/funcs_sysd_linux.go

@@ -52,6 +52,14 @@ func (l *SystemDLogger) DoDebug(d bool) (err error) {
 	return
 }
 
+// GetDebug returns the debug status of this SystemDLogger.
+func (l *SystemDLogger) GetDebug() (d bool) {
+
+	d = l.EnableDebug
+
+	return
+}
+
 /*
 SetPrefix sets the prefix for this SystemDLogger.
 err will always be nil; it's there for interface-compat.
@@ -215,3 +223,11 @@ func (l *SystemDLogger) renderWrite(msg string, prio journal.Priority) {
 
 	return
 }
+
+// ToLogger returns a stdlib log.Logger.
+func (l *SystemDLogger) ToLogger(prio logPrio) (stdLibLog *log.Logger) {
+
+	stdLibLog = log.New(&logWriter{backend: l, prio: prio}, "", 0)
+
+	return
+}

logging/funcs_syslog_nix.go

@@ -1,3 +1,6 @@
+//go:build !(windows || plan9 || wasip1 || js || ios)
+// +build !windows,!plan9,!wasip1,!js,!ios
+
 package logging
 
 import (
@@ -5,7 +8,7 @@ import (
 	"log"
 	"log/syslog"
 
-	`r00t2.io/goutils/multierr`
+	"r00t2.io/goutils/multierr"
 )
 
 // Setup sets up/configures a SyslogLogger and prepares it for use.
@@ -95,6 +98,14 @@ func (l *SyslogLogger) DoDebug(d bool) (err error) {
 	return
 }
 
+// GetDebug returns the debug status of this SyslogLogger.
+func (l *SyslogLogger) GetDebug() (d bool) {
+
+	d = l.EnableDebug
+
+	return
+}
+
 // SetPrefix sets the prefix for this SyslogLogger.
 func (l *SyslogLogger) SetPrefix(prefix string) (err error) {
 
@@ -258,3 +269,11 @@ func (l *SyslogLogger) Warning(s string, v ...interface{}) (err error) {
 
 	return
 }
+
+// ToLogger returns a stdlib log.Logger.
+func (l *SyslogLogger) ToLogger(prio logPrio) (stdLibLog *log.Logger) {
+
+	stdLibLog = log.New(&logWriter{backend: l, prio: prio}, "", 0)
+
+	return
+}

logging/funcs_winlogger_windows.go

@@ -1,15 +1,16 @@
 package logging
 
 import (
-	`errors`
-	`fmt`
-	`os`
-	`os/exec`
-	`syscall`
+	"errors"
+	"fmt"
+	`log`
+	"os"
+	"os/exec"
+	"syscall"
 
-	`golang.org/x/sys/windows/registry`
-	`golang.org/x/sys/windows/svc/eventlog`
-	`r00t2.io/sysutils/paths`
+	"golang.org/x/sys/windows/registry"
+	"golang.org/x/sys/windows/svc/eventlog"
+	"r00t2.io/sysutils/paths"
 )
 
 /*
@@ -150,6 +151,14 @@ func (l *WinLogger) DoDebug(d bool) (err error) {
 	return
 }
 
+// GetDebug returns the debug status of this WinLogger.
+func (l *WinLogger) GetDebug() (d bool) {
+
+	d = l.EnableDebug
+
+	return
+}
+
 // SetPrefix sets the prefix for this WinLogger.
 func (l *WinLogger) SetPrefix(prefix string) (err error) {
 
@@ -334,3 +343,11 @@ func (l *WinLogger) Warning(s string, v ...interface{}) (err error) {
 	return
 
 }
+
+// ToLogger returns a stdlib log.Logger.
+func (l *WinLogger) ToLogger(prio logPrio) (stdLibLog *log.Logger) {
+
+	stdLibLog = log.New(&logWriter{backend: l, prio: prio}, "", 0)
+
+	return
+}

logging/types.go

@@ -2,9 +2,13 @@ package logging
 
 import (
 	"log"
-	`os`
+	"os"
+
+	`r00t2.io/goutils/bitmask`
 )
 
+type logPrio bitmask.MaskBit
+
 /*
 Logger is one of the various loggers offered by this module.
 */
@@ -18,10 +22,12 @@ type Logger interface {
 	Notice(s string, v ...interface{}) (err error)
 	Warning(s string, v ...interface{}) (err error)
 	DoDebug(d bool) (err error)
+	GetDebug() (d bool)
 	SetPrefix(p string) (err error)
 	GetPrefix() (p string, err error)
 	Setup() (err error)
 	Shutdown() (err error)
+	ToLogger(prio logPrio) (stdLibLog *log.Logger)
 }
 
 /*
@@ -86,6 +92,9 @@ type FileLogger struct {
 	writer *os.File
 }
 
+// NullLogger is used mainly for test implementations, mockup code, etc. It does absolutely nothing with all messages sent to it.
+type NullLogger struct{}
+
 // MultiLogger is used to contain one or more Loggers and present them all as a single Logger.
 type MultiLogger struct {
 	/*
@@ -101,3 +110,12 @@ type MultiLogger struct {
 	*/
 	Loggers map[string]Logger
 }
+
+// logWriter is used as a log.Logger and is returned by <Logger>.ToLogger.
+type logWriter struct {
+	backend Logger
+	prio    logPrio
+}
+
+// nullWriter is used as a shortcut by NullLogger.ToLogger.
+type nullWriter struct{}

logging/types_linux.go

@@ -1,9 +1,5 @@
 package logging
 
-import (
-	`log/syslog`
-)
-
 /*
 SystemDLogger (yes, I'm aware it's actually written as "systemd") writes to journald on systemd-enabled systems.
 */
@@ -11,17 +7,3 @@ type SystemDLogger struct {
 	EnableDebug bool
 	Prefix      string
 }
-
-// SyslogLogger writes to syslog on syslog-enabled systems.
-type SyslogLogger struct {
-	EnableDebug bool
-	Prefix      string
-	alert,
-	crit,
-	debug,
-	emerg,
-	err,
-	info,
-	notice,
-	warning *syslog.Writer
-}

logging/types_nix.go

@@ -0,0 +1,22 @@
+//go:build !(windows || plan9 || wasip1 || js || ios)
+// +build !windows,!plan9,!wasip1,!js,!ios
+
+package logging
+
+import (
+	"log/syslog"
+)
+
+// SyslogLogger writes to syslog on syslog-enabled systems.
+type SyslogLogger struct {
+	EnableDebug bool
+	Prefix      string
+	alert,
+	crit,
+	debug,
+	emerg,
+	err,
+	info,
+	notice,
+	warning *syslog.Writer
+}

multierr/funcs.go

@@ -69,6 +69,9 @@ func (e *MultiError) Error() (errStr string) {
 		numErrs = len(e.Errors)
 	}
 
+	e.lock.Lock()
+	defer e.lock.Unlock()
+
 	for idx, err := range e.Errors {
 		if (idx + 1) < numErrs {
 			errStr += fmt.Sprintf("%v%v", err.Error(), e.ErrorSep)
@@ -87,6 +90,9 @@ func (e *MultiError) AddError(err error) {
 		return
 	}
 
+	e.lock.Lock()
+	defer e.lock.Unlock()
+
 	e.Errors = append(e.Errors, err)
 
 }

multierr/types.go

@@ -1,9 +1,14 @@
 package multierr
 
+import (
+	`sync`
+)
+
 // MultiError is a type of error.Error that can contain multiple errors.
 type MultiError struct {
 	// Errors is a slice of errors to combine/concatenate when .Error() is called.
 	Errors []error `json:"errors"`
 	// ErrorSep is a string to use to separate errors for .Error(). The default is "\n".
 	ErrorSep string `json:"separator"`
+	lock sync.Mutex
 }

structutils/consts.go

@@ -0,0 +1,5 @@
+package structutils
+
+const (
+	TagMapTrim tagMapOpt = iota
+)

structutils/funcs.go

@@ -0,0 +1,362 @@
+/*
+   GoUtils - a library to assist with various Golang-related functions
+   Copyright (C) 2020  Brent Saner
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <https://www.gnu.org/licenses/>.
+*/
+
+package structutils
+
+import (
+	`reflect`
+	`strings`
+)
+
+/*
+	TagToBoolMap takes struct field `field` and tag name `tagName`,
+	 optionally with options `opts`, and returns a map of the tag values.
+	The tag value string is assumed to be in the form of:
+		option[,option,option...]
+	and returns a map[string]bool (map[option]true).
+
+	If field does not have tag tagName, m will be nil.
+
+	See the TagMap* constants for opts.
+*/
+func TagToBoolMap(field reflect.StructField, tagName string, opts ...tagMapOpt) (m map[string]bool) {
+
+	var s string
+	var optSplit []string
+	var tagOpts map[tagMapOpt]bool = getTagMapOpts(opts)
+
+	s = field.Tag.Get(tagName)
+
+	if strings.TrimSpace(s) == "" {
+		return
+	}
+
+	optSplit = strings.Split(s, ",")
+	if optSplit == nil || len(optSplit) == 0 {
+		return
+	}
+	m = make(map[string]bool)
+	for _, o := range optSplit {
+		if tagOpts[TagMapTrim] {
+			o = strings.TrimSpace(o)
+		}
+		m[o] = true
+	}
+
+	return
+}
+
+/*
+	TagToBoolMapWithValue is like TagToBoolMap but additionally assumes the first value is an "identifier".
+	The tag value string is assumed to be in the form of:
+		value,option[,option,option...]
+	and returns a map[string]bool (map[option]true) with the value.
+*/
+func TagToBoolMapWithValue(field reflect.StructField, tagName string, opts ...tagMapOpt) (value string, m map[string]bool) {
+
+	var s string
+	var optSplit []string
+	var tagOpts map[tagMapOpt]bool = getTagMapOpts(opts)
+
+	s = field.Tag.Get(tagName)
+
+	if strings.TrimSpace(s) == "" {
+		return
+	}
+
+	optSplit = strings.Split(s, ",")
+	if optSplit == nil || len(optSplit) == 0 {
+		return
+	}
+	m = make(map[string]bool)
+	for idx, o := range optSplit {
+		if idx == 0 {
+			if tagOpts[TagMapTrim] {
+				o = strings.TrimSpace(o)
+			}
+			value = o
+			continue
+		}
+		if tagOpts[TagMapTrim] {
+			o = strings.TrimSpace(o)
+		}
+		m[o] = true
+	}
+
+	return
+}
+
+/*
+	TagToMixedMap combines TagToBoolMap and TagToStringMap.
+	It takes struct field `field` and tag name `tagName`,
+	and returns all single-value options in mapBool, and all key/value options in mapString.
+
+	If field does not have tag tagName, m will be nil.
+
+	See the TagMap* constants for opts.
+*/
+func TagToMixedMap(field reflect.StructField, tagName string, opts ...tagMapOpt) (mapBool map[string]bool, mapString map[string]string) {
+
+	var s string
+	var valStr string
+	var split []string
+	var kvSplit []string
+	var valSplit []string
+	var k string
+	var v string
+	var tagOpts map[tagMapOpt]bool = getTagMapOpts(opts)
+
+	s = field.Tag.Get(tagName)
+
+	if strings.TrimSpace(s) == "" {
+		return
+	}
+
+	split = strings.Split(s, ",")
+	if split == nil || len(split) == 0 {
+		return
+	}
+	mapBool = make(map[string]bool)
+	mapString = make(map[string]string)
+	for _, valStr = range split {
+		if strings.Contains(valStr, "=") {
+			kvSplit = strings.SplitN(valStr, "=", 2)
+			if kvSplit == nil || len(kvSplit) == 0 {
+				continue
+			}
+			k = valSplit[0]
+			switch len(valSplit) {
+			case 1:
+				v = ""
+			case 2:
+				v = kvSplit[1]
+			}
+			if tagOpts[TagMapTrim] {
+				k = strings.TrimSpace(k)
+				v = strings.TrimSpace(v)
+			}
+			mapString[k] = v
+		} else {
+			if tagOpts[TagMapTrim] {
+				valStr = strings.TrimSpace(valStr)
+			}
+			mapBool[valStr] = true
+		}
+	}
+
+	return
+}
+
+/*
+	TagToMixedMapWithValue combines TagToBoolMapWithValue and TagToStringMapWithValue.
+	It takes struct field `field` and tag name `tagName`,
+	and returns all single-value options in mapBool, and all key/value options in mapString
+	along with the first single-value option as value..
+
+	If field does not have tag tagName, m will be nil.
+
+	See the TagMap* constants for opts.
+*/
+func TagToMixedMapWithValue(field reflect.StructField, tagName string, opts ...tagMapOpt) (value string, mapBool map[string]bool, mapString map[string]string) {
+
+	var s string
+	var idx int
+	var valStr string
+	var split []string
+	var kvSplit []string
+	var valSplit []string
+	var k string
+	var v string
+	var tagOpts map[tagMapOpt]bool = getTagMapOpts(opts)
+
+	s = field.Tag.Get(tagName)
+
+	if strings.TrimSpace(s) == "" {
+		return
+	}
+
+	split = strings.Split(s, ",")
+	if split == nil || len(split) == 0 {
+		return
+	}
+	mapBool = make(map[string]bool)
+	mapString = make(map[string]string)
+	for idx, valStr = range split {
+		if idx == 0 {
+			if tagOpts[TagMapTrim] {
+				valStr = strings.TrimSpace(valStr)
+			}
+			value = valStr
+			continue
+		}
+		if strings.Contains(valStr, "=") {
+			kvSplit = strings.SplitN(valStr, "=", 2)
+			if kvSplit == nil || len(kvSplit) == 0 {
+				continue
+			}
+			k = valSplit[0]
+			switch len(valSplit) {
+			case 1:
+				v = ""
+			case 2:
+				v = kvSplit[1]
+			}
+			if tagOpts[TagMapTrim] {
+				k = strings.TrimSpace(k)
+				v = strings.TrimSpace(v)
+			}
+			mapString[k] = v
+		} else {
+			if tagOpts[TagMapTrim] {
+				valStr = strings.TrimSpace(valStr)
+			}
+			mapBool[valStr] = true
+		}
+	}
+
+	return
+}
+
+/*
+	TagToStringMap takes struct field `field` and tag name `tagName`,
+	 optionally with options `opts`, and returns a map of the tag values.
+	The tag value string is assumed to be in the form of:
+		key=value[,key=value,key=value...]
+	and returns a map[string]string (map[key]value).
+	It is proccessed in order; later duplicate keys overwrite previous ones.
+
+	If field does not have tag tagName, m will be nil.
+
+	If only a key is provided with no value, the value in the map will be an empty string.
+	(e.g. "foo,bar=baz" => map[string]string{"foo": "", "bar: "baz"}
+
+	See the TagMap* constants for opts.
+*/
+func TagToStringMap(field reflect.StructField, tagName string, opts ...tagMapOpt) (m map[string]string) {
+
+	var s string
+	var kvSplit []string
+	var valSplit []string
+	var k string
+	var v string
+	var tagOpts map[tagMapOpt]bool = getTagMapOpts(opts)
+
+	s = field.Tag.Get(tagName)
+
+	if strings.TrimSpace(s) == "" {
+		return
+	}
+
+	kvSplit = strings.Split(s, ",")
+	if kvSplit == nil || len(kvSplit) == 0 {
+		return
+	}
+	for _, kv := range kvSplit {
+		valSplit = strings.SplitN(kv, "=", 2)
+		if valSplit == nil || len(valSplit) == 0 {
+			continue
+		}
+		k = valSplit[0]
+		switch len(valSplit) {
+		case 1:
+			v = ""
+		case 2:
+			v = valSplit[1]
+			// It's not possible to have more than 2.
+		}
+		if m == nil {
+			m = make(map[string]string)
+		}
+		if tagOpts[TagMapTrim] {
+			k = strings.TrimSpace(k)
+			v = strings.TrimSpace(v)
+		}
+		m[k] = v
+	}
+
+	return
+}
+
+/*
+	TagToStringMapWithValue is like TagToStringMap but additionally assumes the first value is an "identifier".
+	The tag value string is assumed to be in the form of:
+		value,key=value[,key=value,key=value...]
+	and returns a map[string]string (map[key]value) with the value.
+*/
+func TagToStringMapWithValue(field reflect.StructField, tagName string, opts ...tagMapOpt) (value string, m map[string]string) {
+
+	var s string
+	var kvSplit []string
+	var valSplit []string
+	var k string
+	var v string
+	var tagOpts map[tagMapOpt]bool = getTagMapOpts(opts)
+
+	s = field.Tag.Get(tagName)
+
+	if strings.TrimSpace(s) == "" {
+		return
+	}
+
+	kvSplit = strings.Split(s, ",")
+	if kvSplit == nil || len(kvSplit) == 0 {
+		return
+	}
+	for idx, kv := range kvSplit {
+		if idx == 0 {
+			if tagOpts[TagMapTrim] {
+				kv = strings.TrimSpace(kv)
+			}
+			value = kv
+			continue
+		}
+		valSplit = strings.SplitN(kv, "=", 2)
+		if valSplit == nil || len(valSplit) == 0 {
+			continue
+		}
+		k = valSplit[0]
+		switch len(valSplit) {
+		case 1:
+			v = ""
+		case 2:
+			v = valSplit[1]
+			// It's not possible to have more than 2.
+		}
+		if m == nil {
+			m = make(map[string]string)
+		}
+		if tagOpts[TagMapTrim] {
+			k = strings.TrimSpace(k)
+			v = strings.TrimSpace(v)
+		}
+		m[k] = v
+	}
+
+	return
+}
+
+func getTagMapOpts(opts []tagMapOpt) (optMap map[tagMapOpt]bool) {
+
+	optMap = make(map[tagMapOpt]bool)
+
+	if opts == nil {
+		return
+	}
+
+	return
+}

structutils/types.go

@@ -0,0 +1,5 @@
+package structutils
+
+type (
+	tagMapOpt uint8
+)