kovetskiy / lorg

Easily-customizable Go logger

LORG

Formatting and placeholders

Synopsis

When you set new format for a logger, lorg will examine given string and look for placeholders' signatures which must be used with the following syntax:

${placeholder}
${placeholder[:option]}

• placeholder - unique placeholder name like level or time.
• option - positional argument which will be passed to placeholder function, this argument usually should be used for controlling placeholder behavior. For example, time placeholder use option value instead of time layout.

Level

Level placeholder returns level of current logging entry. level can take 3 positional options:

${level[:format[:alignment[:short]]]}

• format - will be used to format a string representation of logging level;
• alignment - describes how to align resulting string, can be left or right.
• short - use short string representation of logging level, WARNING -> WARN.

Example:

lorg.SetFormat(
    lorg.NewFormat(`[${level}] %s`),
)
lorg.Info("info")
lorg.Warning("warning")

Output:

[INFO] info
[WARNING] warning

Example:

lorg.SetFormat(
    lorg.NewFormat(`${level:[%s]} %s`),
)
lorg.Info("info")
lorg.Warning("warning")

Output:

[INFO] info
[WARNING] warning

Example:

lorg.SetFormat(
    lorg.NewFormat(`${level:[%s]:left} %s`),
)
lorg.Info("info")
lorg.Warning("warning")

Output:

[INFO]    info
[WARNING] warning

Example:

lorg.SetFormat(
    lorg.NewFormat(`${level:[%s]:right} %s`),
)
lorg.Info("info")
lorg.Warning("warning")

Output:

   [INFO] info
[WARNING] warning

Example:

lorg.SetFormat(
    lorg.NewFormat(`${level:[%s]:left:short} %s`),
)
lorg.Info("info")
lorg.Warning("warning")

Output:

[INFO]  info
[WARN]  warning

Example:

lorg.SetFormat(
    lorg.NewFormat(`${level:[%s]:right:short} %s`),
)
lorg.Info("info")
lorg.Warning("warning")
lorg.Debug("debug")

Output:

 [INFO] info
 [WARN] warning
[DEBUG] debug

Time

Time placeholder returns current time. time can take 1 positional option:

${time[:layout]}

• layout - will be to format current time;

Example:

lorg.SetFormat(
    lorg.NewFormat(`${time:15:04:05} %s`),
)
lorg.Info("info")
lorg.Warning("warning")

Output:

09:21:44 info
09:21:44 warning

Example:

lorg.SetFormat(
    lorg.NewFormat(`${time:15:04} %s`),
)
lorg.Info("info")
lorg.Warning("warning")

Output:

09:21 info
09:21 warning

File

File placeholder returns a filename where has been called logging function.

${file[:mode]}

Placeholder accept two modes:

• short - default behavior, return base name of resulting filename.
• long - return full resulting filename

Example:

lorg.SetFormat(
    lorg.NewFormat(`${file} %s`),
)
lorg.Info("info")
lorg.Warning("warning")

Output:

a.go info
a.go warning

Example:

lorg.SetFormat(
    lorg.NewFormat(`${file:short} %s`),
)

lorg.Info("info")
lorg.Warning("warning")

Output:

a.go info
a.go warning

Example:

lorg.SetFormat(
    lorg.NewFormat(`${file:long} %s`),
)
lorg.Info("info")
lorg.Warning("warning")

Output

/home/operator/a.go info
/home/operator/a.go warning

Line

Line placeholder returns a number of line where has been called logging function.

${line}

Example:

lorg.SetFormat(
    lorg.NewFormat(`${line} %s`),
)
lorg.Info("info")
lorg.Warning("warning")

Output:

11 info
12 warning

License

This project is licensed under the terms of the MIT license.