-`LEVEL`: (Default: **Info**) Least severe log events to persist. Case insensitive. The full list of levels can be read in [app.example.ini](https://codeberg.org/forgejo/forgejo/src/branch/forgejo/custom/conf/app.example.ini).
Certain configuration is common to all modes of log output:
-`MODE` is the mode of the log output. It will default to the sublogger
name, thus `[log.console.router]` will default to `MODE = console`.
For mode specific confgurations read further.
-`LEVEL` is the lowest level that this output will log. This value
is inherited from `[log]` and in the case of the non-default loggers
from `[log.sublogger]`.
-`STACKTRACE_LEVEL` is the lowest level that this output will print
a stacktrace. This value is inherited.
-`COLORIZE` will default to `true` for `console` as
described, otherwise it will default to `false`.
### Non-inherited default values
There are several values which are not inherited as described above but
rather default to those specific to type of logger, these are:
`EXPRESSION`, `FLAGS`, `PREFIX` and `FILE_NAME`.
#### `EXPRESSION`
`EXPRESSION` represents a regular expression that log events must match to be logged by the sublogger. Either the log message, (with colors removed), must match or the `longfilename:linenumber:functionname` must match. NB: the whole message or string doesn't need to completely match.
Please note this expression will be run in the sublogger's goroutine
not the logging event subroutine. Therefore it can be complicated.
#### `FLAGS`
`FLAGS` represents the preceding logging context information that is
printed before each message. It is a comma-separated string set. The order of values does not matter.
Possible values are:
-`none` or `,` - No flags.
-`date` - the date in the local time zone: `2009/01/23`.
-`time` - the time in the local time zone: `01:23:23`.
The main intention of these commands is to easily add a temporary logger to investigate problems on running systems where a restart
may cause the issue to disappear.
## Log colorization
Logs to the console will be colorized by default when not running on
Windows. Terminal sniffing will occur on Windows and if it is
determined that we are running on a terminal capable of color we will
colorize.
Further, on \*nix it is becoming common to have file logs that are
colored by default. Therefore file logs will be colorised by default
when not running on Windows.
You can switch on or off colorization by using the `COLORIZE` value.
From a development point of view. If you write
`log.Info("A %s string", "formatted")` the `formatted` part of the log
message will be Bolded on colorized logs.
You can change this by either rendering the formatted string yourself.
Or you can wrap the value in a `log.ColoredValue` struct.
The `log.ColoredValue` struct contains a pointer to value, a pointer to
string of bytes which should represent a color and second set of reset
bytes. Pointers were chosen to prevent copying of large numbers of
values. There are several helper methods:
-`log.NewColoredValue` takes a value and 0 or more color attributes
that represent the color. If 0 are provided it will default to a cached
bold. Note, it is recommended that color bytes constructed from
attributes should be cached if this is a commonly used log message.
-`log.NewColoredValuePointer` takes a pointer to a value, and
0 or more color attributes that represent the color.
-`log.NewColoredValueBytes` takes a value and a pointer to an array
of bytes representing the color.
These functions will not double wrap a `log.ColoredValue`. They will
also set the `resetBytes` to the cached `resetBytes`.
The `colorBytes` and `resetBytes` are not exported to prevent
accidental overwriting of internal values.
## ColorFormat & ColorFormatted
Structs may implement the `log.ColorFormatted` interface by implementing the `ColorFormat(fmt.State)` function.
If a `log.ColorFormatted` struct is logged with `%-v` format, its `ColorFormat` will be used instead of the usual `%v`. The full `fmt.State` will be passed to allow implementers to look at additional flags.
In order to help implementers provide `ColorFormat` methods. There is a
`log.ColorFprintf(...)` function in the log module that will wrap values in `log.ColoredValue` and recognise `%-v`.
In general it is recommended not to make the results of this function too verbose to help increase its versatility. Usually this should simply be an `ID`:`Name`. If you wish to make a more verbose result, it is recommended to use `%-+v` as your marker.
## Log Spoofing protection
In order to protect the logs from being spoofed with cleverly
constructed messages. Newlines are now prefixed with a tab and control
characters except those used in an ANSI CSI are escaped with a
preceding `\` and their octal value.
## Creating a new named logger group
Should a developer wish to create a new named logger, `NEWONE`. It is
recommended to add an `ENABLE_NEWONE_LOG` value to the `[log]`
section, and to add a new `NEWONE` value for the modes.
A function like `func newNewOneLogService()` is recommended to manage
- Configure `logrotate` to match your deployment requirements, see `man 8 logrotate` for configuration syntax details. In the `postrotate/endscript` block send Forgejo a `USR1` signal via `kill -USR1` or `kill -10` to the `forgejo` process itself, or run `forgejo manager logging release-and-reopen` (with the appropriate environment). Ensure that your configurations apply to all files emitted by Forgejo loggers as described in the above sections.
- If you are using docker and are running from outside of the container you can use `docker exec -u $OS_USER $CONTAINER_NAME sh -c 'forgejo manager logging release-and-reopen'` or `docker exec $CONTAINER_NAME sh -c '/bin/s6-svc -1 /etc/s6/gitea/'` or send `USR1` directly to the Forgejo process itself.
The next `logrotate` jobs will include your configurations, so no restart is needed. You can also immediately reload `logrotate` with `logrotate /etc/logrotate.conf --force`.
