From 0deea4a8f369013ec00e231d0c2c37e4ab3f0ba1 Mon Sep 17 00:00:00 2001 From: Siri Hansen Date: Tue, 24 Apr 2018 14:26:31 +0200 Subject: Add logger --- lib/kernel/doc/src/logger_std_h.xml | 81 +++++++++++++++++++++++++++++++++++++ 1 file changed, 81 insertions(+) create mode 100644 lib/kernel/doc/src/logger_std_h.xml (limited to 'lib/kernel/doc/src/logger_std_h.xml') diff --git a/lib/kernel/doc/src/logger_std_h.xml b/lib/kernel/doc/src/logger_std_h.xml new file mode 100644 index 0000000000..2a368b16eb --- /dev/null +++ b/lib/kernel/doc/src/logger_std_h.xml @@ -0,0 +1,81 @@ + + + + +
+ + 2017 + Ericsson AB. All Rights Reserved. + + + Licensed under the Apache License, Version 2.0 (the "License"); + you may not use this file except in compliance with the License. + You may obtain a copy of the License at + + http://www.apache.org/licenses/LICENSE-2.0 + + Unless required by applicable law or agreed to in writing, software + distributed under the License is distributed on an "AS IS" BASIS, + WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + See the License for the specific language governing permissions and + limitations under the License. + + + + logger_std_h + + + + + + + A + logger_std_h.xml +
+ logger_std_h + Default handler for the Logger application. + + +

This is the default handler for the Logger + application. Multiple instances of this handler can be added to + logger, and each instance will print logs to standard_io, + standard_error or to a file.

+ +

To add a new instance, + use logger:add_handler/3 + .

+ +

The handler configuration may contain the following keys, + associated with values as described:

+ + filters + +

A list of {Id,{Fun,Args}}, each representing a filter + that may selct or modify log events to forward to this + handler.

 + filter_default + +

The atom log or stop, specifying what to + do with a log event if all filters + return ignore.

 + formatter + +

{Module,Extra}, + where Module:format(Log,Extra) will be called by + the handler to produce the string that will be printed to + the handler's destination.

 + level + +

The level of log events that logger shall forward to + this handler. Log events of the specified, or more severe + levels, are forwarded.

 + + + + + + + + + -- cgit v1.2.3 From ee44197422710dabe43f2f4b80d1034aae9c916f Mon Sep 17 00:00:00 2001 From: Peter Andersson Date: Wed, 25 Apr 2018 21:18:08 +0200 Subject: Add documentation of the built-in logger handlers --- lib/kernel/doc/src/logger_std_h.xml | 110 ++++++++++++++++++++++++++---------- 1 file changed, 81 insertions(+), 29 deletions(-) (limited to 'lib/kernel/doc/src/logger_std_h.xml') diff --git a/lib/kernel/doc/src/logger_std_h.xml b/lib/kernel/doc/src/logger_std_h.xml index 2a368b16eb..fe9b9ca5a9 100644 --- a/lib/kernel/doc/src/logger_std_h.xml +++ b/lib/kernel/doc/src/logger_std_h.xml @@ -39,42 +39,94 @@

This is the default handler for the Logger application. Multiple instances of this handler can be added to logger, and each instance will print logs to standard_io, - standard_error or to a file.

- -

To add a new instance, - use logger:add_handler/3 + standard_error or to file. The default instance that starts + with kernel is named logger_std_h - which is the name to be used + for reconfiguration.

+

The handler has an overload protection mechanism that will keep the handler + process and the kernel application alive during a high load of log + requests. How this feature works, and how to modify the configuration, + is described in the + User's Guide .

- -

The handler configuration may contain the following keys, - associated with values as described:

+

To add a new instance of the standard handler, use + logger:add_handler/3 + . The handler configuration argument is a map which may contain + general configuration parameters, as documented in the + User's Guide + , as well as handler specific parameters. The specific parameters + are stored in a sub map with the key logger_std_h. The following + keys and values may be specified:

- filters - -

A list of {Id,{Fun,Args}}, each representing a filter - that may selct or modify log events to forward to this - handler.

 - filter_default - -

The atom log or stop, specifying what to - do with a log event if all filters - return ignore.

 - formatter + type -

{Module,Extra}, - where Module:format(Log,Extra) will be called by - the handler to produce the string that will be printed to - the handler's destination.

 - level +

This will have the value standard_io, standard_error, + {file,LogFileName}, or {file,LogFileName,LogFileOpts}, + where standard_io is the default value for type. It's recommended + to not specify LogFileOpts if not absolutely necessary. The + default options used by the handler to open a file for logging are: + raw, append and delayed_write. The standard + handler does not have support for circular logging. Use the + logger_disk_log_h + handler for this.

+ filesync_repeat_interval -

The level of log events that logger shall forward to - this handler. Log events of the specified, or more severe - levels, are forwarded.

 +

This value (in milliseconds) specifies how often the handler will + do a file sync operation in order to make sure that buffered data gets + written to disk. The handler will repeatedly attempt this + operation, but only perform it if something has actually been logged + since the last sync. The default value is 5000 milliseconds. + If no_repeat is set as value, the repeated file sync operation + is disabled, and it will be the operating system settings that determine + how quickly or slowly data gets written to disk. The user can also call + the filesync/1 + function to perform a file sync.

 - +

There are a number of other configuration parameters available, that are + to be used for customizing the overload protection behaviour. The same + parameters are used both in the standard handler and the disk_log handler, + and are documented in the + User's Guide + .

+

Note that when changing the configuration of the handler in runtime, by + calling + logger:set_handler_config/2 + , or + logger:set_handler_config/3 + , + the type parameter may not be modified.

+

Example of adding a standard handler:

+ +logger:add_handler(my_standard_h, logger_std_h, + #{level => info, + filter_default => log, + logger_std_h => + #{type => {file,"./system_info.log"}, + filesync_repeat_interval => 1000}}). + +

In order to configure the default handler (that starts initially with + the kernel application) to log to file instead of standard_io, + use the kernel configuration parameter + logger_dest with + value {file,FileName}. Example:

+ +erl -kernel logger_dest '{file,"./erl.log"}' + +

An example of how to replace the standard handler with a disk_log handler + at startup can be found in the manual of + logger_disk_log_h.

- + + + + + Writes buffered data to disk. + +

Write buffered data to disk.

+ + + + -- cgit v1.2.3