From 224a42d658d3c08e3ce080fa8041c161e16f3863 Mon Sep 17 00:00:00 2001
From: Siri Hansen <siri@erlang.org>
Date: Thu, 20 Sep 2018 16:56:26 +0200
Subject: [logger] Add SetOrUpdate parameter to handler callback
 changing_config

Since logger has now knowledge of the handler specific data ('config'
field in the handler configuration map), it can not merge this data
structure with default or old values upon configuration
change. Instead, the handler callback changing_config must do
this. Earlier, this callback did not reflect if the configuration
change was initiated by a call to set_handler_config or
update_handler_config, so the handler did not know if unspecified
fields should get default values or the values from the existing
configuration.

To overcome this problem, the new parameter SetOrUpdate is added to
this callback. If SetOrUpdate equals set, then default values should
be used. If SetOrUpdate equals update, then existing configuration
values should be used.
---
 lib/kernel/doc/src/logger_chapter.xml | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

(limited to 'lib/kernel/doc/src/logger_chapter.xml')

diff --git a/lib/kernel/doc/src/logger_chapter.xml b/lib/kernel/doc/src/logger_chapter.xml
index 4a81cfa34a..7e88f82dad 100644
--- a/lib/kernel/doc/src/logger_chapter.xml
+++ b/lib/kernel/doc/src/logger_chapter.xml
@@ -384,7 +384,7 @@ 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/2</c>
+      functions <c>adding_handler/1</c>, <c>changing_config/3</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
@@ -1024,7 +1024,7 @@ ok</pre>
     <list>
       <item><c>adding_handler(Config)</c></item>
       <item><c>removing_handler(Config)</c></item>
-      <item><c>changing_config(OldConfig, NewConfig)</c></item>
+      <item><c>changing_config(SetOrUpdate, OldConfig, NewConfig)</c></item>
     </list>
     <p>When a handler is added, by for example a call
       to <seealso marker="logger#add_handler-3">
@@ -1045,7 +1045,7 @@ ok</pre>
       or <seealso marker="logger#update_handler_config/2">
 	<c>logger:update_handler_config/2</c></seealso> is called,
       Logger
-      calls <c>HModule:changing_config(OldConfig, NewConfig)</c>. If
+      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>
 
-- 
cgit v1.2.3