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authorSiri Hansen <[email protected]>2018-10-03 12:21:23 +0200
committerSiri Hansen <[email protected]>2018-10-03 13:06:25 +0200
commit6fae4fbd3650366730d35988ee588c32848dbecc (patch)
treed204f1bf65439f6da5a3ec35e491bd4385752530 /lib/kernel/doc
parent1838418b9193140f6ba5f5716884b62aad7b662d (diff)
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[logger] Add handler callback filter_config/1
This function is called when a logger API function for fetching handler configuration is called. The point is to allow the handler to remove internal data fields that it might have stored in the configuration database, before returning the handler configuration to the caller. An example of such internal data are the 'handler_pid' and 'mode_tab' fields that logger_std_h and logger_disk_log_h store in their configuration maps.
Diffstat (limited to 'lib/kernel/doc')
-rw-r--r--lib/kernel/doc/src/logger.xml20
-rw-r--r--lib/kernel/doc/src/logger_chapter.xml12
2 files changed, 30 insertions, 2 deletions
diff --git a/lib/kernel/doc/src/logger.xml b/lib/kernel/doc/src/logger.xml
index aa6e17f27b..2bcf137299 100644
--- a/lib/kernel/doc/src/logger.xml
+++ b/lib/kernel/doc/src/logger.xml
@@ -1123,6 +1123,26 @@ logger:set_process_metadata(maps:merge(logger:get_process_metadata(), Meta)).
</func>
<func>
+ <name>HModule:filter_config(Config) -> FilteredConfig</name>
+ <fsummary>Remove internal data from configuration.</fsummary>
+ <type>
+ <v>Config = FilteredConfig =
+ <seealso marker="#type-handler_config">handler_config()</seealso></v>
+ </type>
+ <desc>
+ <p>This callback function is optional.</p>
+ <p>The function is called when one of the Logger API functions
+ for fetching the handler configuration is called, for
+ example
+ <seealso marker="#get_handler_config-1">
+ <c>logger:get_handler_config/1</c></seealso>.</p>
+ <p>It allows the handler to remove internal data fields from
+ its configuration data before it is returned to the
+ caller.</p>
+ </desc>
+ </func>
+
+ <func>
<name>HModule:log(LogEvent, Config) -> void()</name>
<fsummary>Log the given log event.</fsummary>
<type>
diff --git a/lib/kernel/doc/src/logger_chapter.xml b/lib/kernel/doc/src/logger_chapter.xml
index 777c37058e..1870d2ab79 100644
--- a/lib/kernel/doc/src/logger_chapter.xml
+++ b/lib/kernel/doc/src/logger_chapter.xml
@@ -384,8 +384,8 @@ logger:debug(#{got => connection_request, id => Id, state => State},
<p>In addition to the mandatory callback function <c>log/2</c>, a
handler module can export the optional callback
- functions <c>adding_handler/1</c>, <c>changing_config/3</c>
- and <c>removing_handler/1</c>. See
+ functions <c>adding_handler/1</c>, <c>changing_config/3</c>,
+ <c>filter_config/1</c>, and <c>removing_handler/1</c>. See
section <seealso marker="logger#handler_callback_functions">Handler
Callback Functions</seealso> in the logger(3) manual page for
more information about these function.</p>
@@ -1029,6 +1029,7 @@ ok</pre>
<item><c>adding_handler(Config)</c></item>
<item><c>removing_handler(Config)</c></item>
<item><c>changing_config(SetOrUpdate, OldConfig, NewConfig)</c></item>
+ <item><c>filter_config(Config)</c></item>
</list>
<p>When a handler is added, by for example a call
to <seealso marker="logger#add_handler-3">
@@ -1052,6 +1053,13 @@ ok</pre>
calls <c>HModule:changing_config(SetOrUpdate, OldConfig, NewConfig)</c>. If
this function returns <c>{ok,NewConfig1}</c>, Logger
writes <c>NewConfig1</c> to the configuration database.</p>
+ <p>When <seealso marker="logger#get_config-0">
+ <c>logger:get_config/0</c></seealso> or
+ <seealso marker="logger#get_handler_config-0">
+ <c>logger:get_handler_config/0,1</c></seealso> is called,
+ Logger calls <c>HModule:filter_config(Config)</c>. This function
+ must return the handler configuration where internal data is
+ removed.</p>
<p>A simple handler that prints to the terminal can be implemented
as follows:</p>