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Package log

import "github.com/Diarkis/diarkis/log"
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Package log ▷

Log

Diarkis logger.

Log Configurations

Log configurations are explained below. 

{
  "level": "verbose",
  "timeZone": "local",
  "color": true,
  "flat": false,
  "filePath": "path/to/log/file"
}

Configuration Values 

level - Default is "verbose"

Controls logger level: verbose < network < sys < debug(trace) < info < notice < warn < error < fatal. 

+----------------+----------------------------------------------------------------------------------------------------+---------+
| Log Level Name | Description                                                                                        |         |
+----------------+----------------------------------------------------------------------------------------------------+---------+
| verbose        | Lowest logging level to see what is taking place under the hood. Must never be used in production. | Default |
| network        | Lower than sys log level to output UDP/TCP network related logs.                                   |         |
| sys            | Second lowest logging level to log more detailed information.                                      |         |
| debug          | Logging debug purpose information usually expected to be used in application level of the code.    |         |
| info           | Logging starting and shutting down log as well as other must see information.                      |         |
| notice         | Should be used to log information that is important for the application, but not as critical.      |         |
| warn           | Warning information that is not errors, but should be logged and reviewed later.                   |         |
| error          | Errors that may be caused by either the user or the application.                                   |         |
| fatal          | Logging of unrecoverable problems.                                                                 |         |
+----------------+----------------------------------------------------------------------------------------------------+---------+

We suggest using log level info for production. 

timeZone - Default is "utc"

Valid configuration value are "utc" or "local". Default is UTC. 

+----------------+-----------------+---------+
| Time Zone Name | Description     |         |
+----------------+-----------------+---------+
| utc            | UTC Time zone   | Default |
| local          | Local time zone |         |
+----------------+-----------------+---------+

We suggest using UTC time zone for multiple cluster envrionment. 

color - Default is true

If false, the output log has no color. The default is true. 

flat - Default is false

If set to true, logging data will not contain linkbreaks. This configuration is recommanded to be paired to env DIARKIS_JSON_LOG=true. 

filePath - Default is ""

File path to output log data to (absolute path).

The absolute file path to write the logging data to. This configuration should be used if you need to leave log files somewhere on disk. Leave this empty to disable it.

Environment Variable Used By Log Module 

DIARKIS_JSON_LOG=true

This converts all output log into StackDriver formatted JSON log.

Change Log Level in Runtime

Diarkis logger allows you to change the current log level of a running server without stopping.

1. Create a signal command file named DIARKIS_SIGUSR1 under /tmp/ directory. It should look like this: /tmp/DIARKIS_SIGUSR1

2. Write LogLevelChange in DIARKIS_SIGUSR1 file

3. Send a SIGUSR1 signal to the target Diarkis server process.

  • This will look for the command file under /tmp/ and executes what the file says, which is LogLevelChange.

4. This will change the current log level.

  • The order of log level change is: verbose → network → sys → debug → info Keep sending the signal until the log level is changed to the desired level.

Formmated Logging

Log module lets you format logging outputs and it surports JSON format as well.

Formatted Text Logging Example: 

logger.Debugf("Debugging logging", "RoomID", roomID, "Object pointer address", obj)
// Output:
// Debug logging	RoomID=[Value="19324322303022354543345" Type=string Pointer=NA]	Object=[Value={"Name":"Example Object","Value":1203} Type=*Object Pointer=0x005a134]

Formatted JSON Logging Example: 

logger.Debugf("Debugging logging", "RoomID", roomID, "Object", obj)
// JSON Output:
// {
//   "logName":"Test",
//   "severity":"100",
//   "resource": {
//       "type":"Server",
//       "labels": {
//         "Message":"Debug logging",
//         "RoomID":{ "Value":"19324322303022354543345", "Type":"string","Pointer":"NA"},
//         "Object":{
//           "Type":"*Object",
//           "Pointer":"0x005a134",
//           "Value": {
//             "Name":"Example Object",
//             "Value": 1203
//           },
//         }
//       }
//     },
//     "timestamp":"2019-10-12T07:20:50.52Z"
//   }
// }

Index ▾

func CloseFileOutput(next func(error))
func FmtBlue(msg string) string
func FmtDBlue(msg string) string
func FmtGreen(msg string) string
func FmtGrey(msg string) string
func FmtLBlue(msg string) string
func FmtPurple(msg string) string
func FmtRed(msg string) string
func FmtRedBg(msg string) string
func FmtYellow(msg string) string
func FormatStruct(cb func(v interface{}) string)
func IsDebug() bool
func IsError() bool
func IsFatal() bool
func IsInfo() bool
func IsNetwork() bool
func IsNotice() bool
func IsSys() bool
func IsVerbose() bool
func IsWarn() bool
func Level(_level int)
func SetCustomOutput(custom func(formatted bool, name string, prefix string, level string, vals []interface{}) string)
func SetDebugLevel()
func SetErrorLevel()
func SetFatalLevel()
func SetInfoLevel()
func SetNetworkLevel()
func SetNoticeLevel()
func SetPrefix(prefix string)
func SetSysLevel()
func SetVerboseLevel()
func SetWarnLevel()
func Setup(confpath string)
func UpdateConfigs(configs map[string]interface{})
func UseCustomOutput()
func UseJSONFormat()
func UseStackdriverLogging()
type Logger
    func New(name string) *Logger
    func (logger *Logger) Debug(vals ...interface{})
    func (logger *Logger) Debugf(vals ...interface{})
    func (logger *Logger) DisableCustom()
    func (logger *Logger) EnableCustom()
    func (logger *Logger) Error(vals ...interface{})
    func (logger *Logger) Errorf(vals ...interface{})
    func (logger *Logger) Fatal(vals ...interface{})
    func (logger *Logger) Fatalf(vals ...interface{})
    func (logger *Logger) Fmt(msg string, vals ...interface{}) string
    func (logger *Logger) FmtDebug(vals ...interface{}) string
    func (logger *Logger) FmtError(vals ...interface{}) string
    func (logger *Logger) FmtFatal(vals ...interface{}) string
    func (logger *Logger) FmtInfo(vals ...interface{}) string
    func (logger *Logger) FmtNetwork(vals ...interface{}) string
    func (logger *Logger) FmtNotice(vals ...interface{}) string
    func (logger *Logger) FmtSys(vals ...interface{}) string
    func (logger *Logger) FmtVerbose(vals ...interface{}) string
    func (logger *Logger) FmtWarn(vals ...interface{}) string
    func (logger *Logger) FormatStruct(cb func(v interface{}) string)
    func (logger *Logger) Info(vals ...interface{})
    func (logger *Logger) Infof(vals ...interface{})
    func (logger *Logger) Network(vals ...interface{})
    func (logger *Logger) Networkf(vals ...interface{})
    func (logger *Logger) Notice(vals ...interface{})
    func (logger *Logger) Noticef(vals ...interface{})
    func (logger *Logger) Sys(vals ...interface{})
    func (logger *Logger) Sysf(vals ...interface{})
    func (logger *Logger) Trace(vals ...interface{})
    func (logger *Logger) Verbose(vals ...interface{})
    func (logger *Logger) Verbosef(vals ...interface{})
    func (logger *Logger) Warn(vals ...interface{})
    func (logger *Logger) Warnf(vals ...interface{})
    func (logger *Logger) Write(vals ...interface{})

func CloseFileOutput 

func CloseFileOutput(next func(error))

CloseFileOutput [INTERNAL USE ONLY] Closes the file descriptor of log data if used

func FmtBlue 

func FmtBlue(msg string) string

FmtBlue Colorize the given string

func FmtDBlue 

func FmtDBlue(msg string) string

FmtDBlue Colorize the given string

func FmtGreen 

func FmtGreen(msg string) string

FmtGreen Colorize the given string

func FmtGrey 

func FmtGrey(msg string) string

FmtGrey Colorize the given string

func FmtLBlue 

func FmtLBlue(msg string) string

FmtLBlue Colorize the given string

func FmtPurple 

func FmtPurple(msg string) string

FmtPurple Colorize the given string

func FmtRed 

func FmtRed(msg string) string

FmtRed Colorize the given string

func FmtRedBg 

func FmtRedBg(msg string) string

FmtRedBg Colorize the given string

func FmtYellow 

func FmtYellow(msg string) string

FmtYellow Colorize the given string

func FormatStruct 

func FormatStruct(cb func(v interface{}) string)

FormatStruct assigns an optional callback to be called from Verbosef, Networkf, Sysf, Debugf, Noticef, Infof, Warnf, Errorf, and Fatalf to format struct variable being passed. 

[CRITICALLY IMPORTANT] Do not use mutex lock or functions that uses mutex lock of any kind internally to avoid possible mutext dead-lock.
[CRITICALLY IMPORTANT] Do not attempt to print maps to avoid possible fatal error of concurrent map read and write.

func IsDebug 

func IsDebug() bool

IsDebug returns true if the log level is debug

func IsError 

func IsError() bool

IsError returns true if the log level is error

func IsFatal 

func IsFatal() bool

IsFatal returns true if the log level is fatal

func IsInfo 

func IsInfo() bool

IsInfo returns true if the log level is info

func IsNetwork 

func IsNetwork() bool

IsNetwork returns true if the log level is network

func IsNotice 

func IsNotice() bool

IsNotice returns true if the log level is notice

func IsSys 

func IsSys() bool

IsSys returns true if the log level is sys

func IsVerbose 

func IsVerbose() bool

IsVerbose returns true if the log level is verbose

func IsWarn 

func IsWarn() bool

IsWarn returns true if the log level is warn

func Level 

func Level(_level int)

Level Sets logging level

func SetCustomOutput 

func SetCustomOutput(custom func(formatted bool, name string, prefix string, level string, vals []interface{}) string)

SetCustomOutput Registers a custom function to create a log output string

func SetDebugLevel 

func SetDebugLevel()

SetDebugLevel set log level to debug

func SetErrorLevel 

func SetErrorLevel()

SetErrorLevel set log level to error

func SetFatalLevel 

func SetFatalLevel()

SetFatalLevel set log level to fatal

func SetInfoLevel 

func SetInfoLevel()

SetInfoLevel set log level to info

func SetNetworkLevel 

func SetNetworkLevel()

SetNetworkLevel set log level to sys

func SetNoticeLevel 

func SetNoticeLevel()

SetNoticeLevel set log level to notice

func SetPrefix 

func SetPrefix(prefix string)

SetPrefix Sets a prefix for every log

func SetSysLevel 

func SetSysLevel()

SetSysLevel set log level to sys

func SetVerboseLevel 

func SetVerboseLevel()

SetVerboseLevel set log level to verbose

func SetWarnLevel 

func SetWarnLevel()

SetWarnLevel set log level to warn

func Setup 

func Setup(confpath string)

Setup Load a configuration file into memory - pass an empty string to load nothing

func UpdateConfigs 

func UpdateConfigs(configs map[string]interface{})

UpdateConfigs Apply configurations It can be executed in runtime to update the configurations also

func UseCustomOutput 

func UseCustomOutput()

UseCustomOutput Enables custom output for all log data.

func UseJSONFormat 

func UseJSONFormat()

UseJSONFormat formats the log with JSON format.

func UseStackdriverLogging 

func UseStackdriverLogging()

UseStackdriverLogging is an alias of UseJSONFormat

type Logger

Logger Logger data structure 

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

func New 

func New(name string) *Logger

New Creates a new logger

func (*Logger) Debug 

func (logger *Logger) Debug(vals ...interface{})

Debug Outputs a log to stdout stream

func (*Logger) Debugf 

func (logger *Logger) Debugf(vals ...interface{})

Debugf returns an instance of FormattedText struct.

This is useful when you need to format the logging message. 

[IMPORTANT] FormattedText supports JSON format log output as well.

Example: 

logger.Debugf("This is a log", "intVar", 123, "stringVar", "aaa", "object", obj)
// output:
// This is a log	intVar=[Value=="123" Type=int Pointer=NA] 	stringVar=[Value="aaa" Type=string Pointer=NA]	object=[Value={"Name":"exampleObject","Counter":100} Type=*Object Pointer=0x0ff234]

func (*Logger) DisableCustom 

func (logger *Logger) DisableCustom()

DisableCustom blocks logger.Write()

func (*Logger) EnableCustom 

func (logger *Logger) EnableCustom()

EnableCustom allows logger.Write()

func (*Logger) Error 

func (logger *Logger) Error(vals ...interface{})

Error Outputs a log to stdout stream

func (*Logger) Errorf 

func (logger *Logger) Errorf(vals ...interface{})

Errorf returns an instance of FormattedText struct.

This is useful when you need to format the logging message. 

[IMPORTANT] FormattedText supports JSON format log output as well.

Example: 

logger.Errorf("This is a log", "intVar", 123, "stringVar", "aaa", "object", obj)
// output:
// This is a log	intVar=[Value=="123" Type=int Pointer=NA] 	stringVar=[Value="aaa" Type=string Pointer=NA]	object=[Value={"Name":"exampleObject","Counter":100} Type=*Object Pointer=0x0ff234]

func (*Logger) Fatal 

func (logger *Logger) Fatal(vals ...interface{})

Fatal Outputs a log to stdout stream

func (*Logger) Fatalf 

func (logger *Logger) Fatalf(vals ...interface{})

Fatalf returns an instance of FormattedText struct.

This is useful when you need to format the logging message. 

[IMPORTANT] FormattedText supports JSON format log output as well.

Example: 

logger.Fatalf("This is a log", "intVar", 123, "stringVar", "aaa", "object", obj)
// output:
// This is a log	intVar=[Value=="123" Type=int Pointer=NA] 	stringVar=[Value="aaa" Type=string Pointer=NA]	object=[Value={"Name":"exampleObject","Counter":100} Type=*Object Pointer=0x0ff234]

func (*Logger) Fmt 

func (logger *Logger) Fmt(msg string, vals ...interface{}) string

Fmt uses fmt.Sprintf internally

func (*Logger) FmtDebug 

func (logger *Logger) FmtDebug(vals ...interface{}) string

FmtDebug Formats given strings and returns it for logging purpose

func (*Logger) FmtError 

func (logger *Logger) FmtError(vals ...interface{}) string

FmtError Formats given strings and returns it for logging purpose

func (*Logger) FmtFatal 

func (logger *Logger) FmtFatal(vals ...interface{}) string

FmtFatal Formats given strings and returns it for logging purpose

func (*Logger) FmtInfo 

func (logger *Logger) FmtInfo(vals ...interface{}) string

FmtInfo Formats given strings and returns it for logging purpose

func (*Logger) FmtNetwork 

func (logger *Logger) FmtNetwork(vals ...interface{}) string

FmtNetwork Formats given strings and returns it for logging purpose

func (*Logger) FmtNotice 

func (logger *Logger) FmtNotice(vals ...interface{}) string

FmtNotice Formats given strings and returns it for logging purpose

func (*Logger) FmtSys 

func (logger *Logger) FmtSys(vals ...interface{}) string

FmtSys Formats given strings and returns it for logging purpose

func (*Logger) FmtVerbose 

func (logger *Logger) FmtVerbose(vals ...interface{}) string

FmtVerbose Formats given strings and returns it for logging purpose

func (*Logger) FmtWarn 

func (logger *Logger) FmtWarn(vals ...interface{}) string

FmtWarn Formats given strings and returns it for logging purpose

func (*Logger) FormatStruct 

func (logger *Logger) FormatStruct(cb func(v interface{}) string)

FormatStruct assigns an optional callback to be called from Verbosef, Networkf, Sysf, Debugf, Noticef, Infof, Warnf, Errorf, and Fatalf to format struct variable being passed.

func (*Logger) Info 

func (logger *Logger) Info(vals ...interface{})

Info Outputs a log to stdout stream

func (*Logger) Infof 

func (logger *Logger) Infof(vals ...interface{})

Infof returns an instance of FormattedText struct.

This is useful when you need to format the logging message. 

[IMPORTANT] FormattedText supports JSON format log output as well.

Example: 

logger.Infof("This is a log", "intVar", 123, "stringVar", "aaa", "object", obj)
// output:
// This is a log	intVar=[Value=="123" Type=int Pointer=NA] 	stringVar=[Value="aaa" Type=string Pointer=NA]	object=[Value={"Name":"exampleObject","Counter":100} Type=*Object Pointer=0x0ff234]

func (*Logger) Network 

func (logger *Logger) Network(vals ...interface{})

Network Outputs a log to stdout stream

func (*Logger) Networkf 

func (logger *Logger) Networkf(vals ...interface{})

Networkf returns an instance of FormattedText struct.

This is useful when you need to format the logging message. 

[IMPORTANT] FormattedText supports JSON format log output as well.

Example: 

logger.Networkf("This is a log", "intVar", 123, "stringVar", "aaa", "object", obj)
// output:
// This is a log	intVar=[Value=="123" Type=int Pointer=NA] 	stringVar=[Value="aaa" Type=string Pointer=NA]	object=[Value={"Name":"exampleObject","Counter":100} Type=*Object Pointer=0x0ff234]

func (*Logger) Notice 

func (logger *Logger) Notice(vals ...interface{})

Notice Outputs a log to stdout stream

func (*Logger) Noticef 

func (logger *Logger) Noticef(vals ...interface{})

Noticef returns an instance of FormattedText struct.

This is useful when you need to format the logging message. 

[IMPORTANT] FormattedText supports JSON format log output as well.

Example: 

logger.Noticef("This is a log", "intVar", 123, "stringVar", "aaa", "object", obj)
// output:
// This is a log	intVar=[Value=="123" Type=int Pointer=NA] 	stringVar=[Value="aaa" Type=string Pointer=NA]	object=[Value={"Name":"exampleObject","Counter":100} Type=*Object Pointer=0x0ff234]

func (*Logger) Sys 

func (logger *Logger) Sys(vals ...interface{})

Sys Outputs a log to stdout stream

func (*Logger) Sysf 

func (logger *Logger) Sysf(vals ...interface{})

Sysf returns an instance of FormattedText struct.

This is useful when you need to format the logging message. 

[IMPORTANT] FormattedText supports JSON format log output as well.

Example: 

logger.Sysf("This is a log", "intVar", 123, "stringVar", "aaa", "object", obj)
// output:
// This is a log	intVar=[Value=="123" Type=int Pointer=NA] 	stringVar=[Value="aaa" Type=string Pointer=NA]	object=[Value={"Name":"exampleObject","Counter":100} Type=*Object Pointer=0x0ff234]

func (*Logger) Trace 

func (logger *Logger) Trace(vals ...interface{})

Trace Outputs a log to stdout stream as Sys level log with stack trace. Useful for debugging

func (*Logger) Verbose 

func (logger *Logger) Verbose(vals ...interface{})

Verbose Outputs a log to stdout stream

func (*Logger) Verbosef 

func (logger *Logger) Verbosef(vals ...interface{})

Verbosef returns an instance of FormattedText struct.

This is useful when you need to format the logging message. 

[IMPORTANT] FormattedText supports JSON format log output as well.

Example: 

logger.Verbosef("This is a log", "intVar", 123, "stringVar", "aaa", "object", obj)
// output:
// This is a log	intVar=[Value=="123" Type=int Pointer=NA] 	stringVar=[Value="aaa" Type=string Pointer=NA]	object=[Value={"Name":"exampleObject","Counter":100} Type=*Object Pointer=0x0ff234]

func (*Logger) Warn 

func (logger *Logger) Warn(vals ...interface{})

Warn Outputs a log to stdout stream

func (*Logger) Warnf 

func (logger *Logger) Warnf(vals ...interface{})

Warnf returns an instance of FormattedText struct.

This is useful when you need to format the logging message. 

[IMPORTANT] FormattedText supports JSON format log output as well.

Example: 

logger.Warnf("This is a log", "intVar", 123, "stringVar", "aaa", "object", obj)
// output:
// This is a log	intVar=[Value=="123" Type=int Pointer=NA] 	stringVar=[Value="aaa" Type=string Pointer=NA]	object=[Value={"Name":"exampleObject","Counter":100} Type=*Object Pointer=0x0ff234]

func (*Logger) Write 

func (logger *Logger) Write(vals ...interface{})

Write outputs a log to stdout stream

Subdirectories

Name Synopsis
..
lib
colorize
msg
std