Add logger

12 files changed, 1671 insertions, 5 deletions

diff --git a/lib/kernel/doc/src/Makefile b/lib/kernel/doc/src/Makefile
index 2413541082..10bdf46119 100644
--- a/lib/kernel/doc/src/Makefile
+++ b/lib/kernel/doc/src/Makefile
@@ -56,6 +56,10 @@ XML_REF3_FILES = application.xml \
 	inet.xml \
 	inet_res.xml \
 	init_stub.xml \
+        logger.xml \
+        logger_std_h.xml \
+        logger_filters.xml \
+        logger_formatter.xml \
 	net_adm.xml \
 	net_kernel.xml \
 	os.xml \
@@ -70,11 +74,17 @@ XML_REF4_FILES = app.xml config.xml
 
 XML_REF6_FILES = kernel_app.xml
 
-XML_PART_FILES =
-XML_CHAPTER_FILES = notes.xml
+XML_PART_FILES = part.xml
+XML_CHAPTER_FILES = \
+        notes.xml \
+        introduction_chapter.xml \
+	logger_chapter.xml
 
 BOOK_FILES = book.xml
 
+IMAGE_FILES = \
+	logger_arch.png
+
 XML_FILES = \
 	$(BOOK_FILES) $(XML_CHAPTER_FILES) \
 	$(XML_PART_FILES) $(XML_REF3_FILES) $(XML_REF4_FILES)\
@@ -111,7 +121,7 @@ SPECS_FLAGS = -I../../include
 # ----------------------------------------------------
 # Targets
 # ----------------------------------------------------
-$(HTMLDIR)/%.gif: %.gif
+$(HTMLDIR)/%: %
 	$(INSTALL_DATA) $< $@
 
 docs: man pdf html
@@ -120,11 +130,12 @@ $(TOP_PDF_FILE): $(XML_FILES)
 
 pdf: $(TOP_PDF_FILE)
 
-html: gifs $(HTML_REF_MAN_FILE)
+html: images $(HTML_REF_MAN_FILE)
 
 man: $(MAN3_FILES) $(MAN4_FILES) $(MAN6_FILES)
 
-gifs: $(GIF_FILES:%=$(HTMLDIR)/%)
+images: $(IMAGE_FILES:%=$(HTMLDIR)/%)
+
 debug opt:
 
 clean clean_docs:
diff --git a/lib/kernel/doc/src/book.xml b/lib/kernel/doc/src/book.xml
index 81a87d126d..0b69b547e7 100644
--- a/lib/kernel/doc/src/book.xml
+++ b/lib/kernel/doc/src/book.xml
@@ -34,6 +34,9 @@
   <preamble>
     <contents level="2"></contents>
   </preamble>
+  <parts lift="yes">
+    <xi:include href="part.xml"/>
+  </parts>
   <applications>
     <xi:include href="ref_man.xml"/>
   </applications>
diff --git a/lib/kernel/doc/src/introduction_chapter.xml b/lib/kernel/doc/src/introduction_chapter.xml
new file mode 100644
index 0000000000..6e6990ddda
--- /dev/null
+++ b/lib/kernel/doc/src/introduction_chapter.xml
@@ -0,0 +1,64 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<!DOCTYPE chapter SYSTEM "chapter.dtd">
+
+<chapter>
+  <header>
+    <copyright>
+      <year>2017</year>
+      <holder>Ericsson AB. All Rights Reserved.</holder>
+    </copyright>
+    <legalnotice>
+      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.
+    
+    </legalnotice>
+
+    <title>Introduction</title>
+    <prepared></prepared>
+    <responsible></responsible>
+    <docno></docno>
+    <approved></approved>
+    <checked></checked>
+    <date></date>
+    <rev></rev>
+    <file>introduction.xml</file>
+  </header>
+
+  <section>
+    <title>Scope</title>
+    <p>The Kernel application has all the code necessary to run
+      the Erlang runtime system: file servers, code servers,
+      and so on.</p>
+    <p>The Kernel application is the first application started. It is
+      mandatory in the sense that the minimal system based on
+      Erlang/OTP consists of Kernel and STDLIB. Kernel
+      contains the following functional areas:</p>
+    <list type="bulleted">
+      <item>Start, stop, supervision, configuration, and distribution of applications</item>
+      <item>Code loading</item>
+      <item>Logging</item>
+      <item>Error logging</item>
+      <item>Global name service</item>
+      <item>Supervision of Erlang/OTP</item>
+      <item>Communication with sockets</item>
+      <item>Operating system interface</item>
+    </list>
+  </section>
+
+  <section>
+    <title>Prerequisites</title>
+    <p>It is assumed that the reader is familiar with the Erlang programming
+      language.</p> 
+  </section>
+</chapter>
+
+
diff --git a/lib/kernel/doc/src/logger.xml b/lib/kernel/doc/src/logger.xml
new file mode 100644
index 0000000000..66e6e5c689
--- /dev/null
+++ b/lib/kernel/doc/src/logger.xml
@@ -0,0 +1,478 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<!DOCTYPE erlref SYSTEM "erlref.dtd">
+
+<erlref>
+  <header>
+    <copyright>
+      <year>2017</year>
+      <holder>Ericsson AB. All Rights Reserved.</holder>
+    </copyright>
+    <legalnotice>
+      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.
+
+    </legalnotice>
+
+    <title>logger</title>
+    <prepared></prepared>
+    <responsible></responsible>
+    <docno></docno>
+    <approved></approved>
+    <checked></checked>
+    <date></date>
+    <rev>A</rev>
+    <file>logger.xml</file>
+  </header>
+  <module>logger</module>
+  <modulesummary>API module for the logger application.</modulesummary>
+
+  <description>
+
+  </description>
+
+  <datatypes>
+    <datatype>
+      <name name="level"/>
+      <desc>
+	<p>The severity level for the message to be logged.</p>
+      </desc>
+    </datatype>
+    <datatype>
+      <name name="log"/>
+      <desc>
+	<p></p>
+      </desc>
+    </datatype>
+    <datatype>
+      <name name="report"/>
+      <desc>
+	<p></p>
+      </desc>
+    </datatype>
+    <datatype>
+      <name name="msg_fun"/>
+      <desc>
+	<p></p>
+      </desc>
+    </datatype>
+    <datatype>
+      <name name="metadata"/>
+      <desc>
+	<p>Metadata associated with the message to be logged.</p>
+      </desc>
+    </datatype>
+    <datatype>
+      <name name="config"/>
+      <desc>
+	<p></p>
+      </desc>
+    </datatype>
+    <datatype>
+      <name name="handler_id"/>
+      <desc>
+	<p></p>
+      </desc>
+    </datatype>
+    <datatype>
+      <name name="filter_id"/>
+      <desc>
+	<p></p>
+      </desc>
+    </datatype>
+    <datatype>
+      <name name="filter"/>
+      <desc>
+	<p></p>
+      </desc>
+    </datatype>
+    <datatype>
+      <name name="filter_return"/>
+      <desc>
+	<p></p>
+      </desc>
+    </datatype>
+  </datatypes>
+
+  <section>
+    <title>Macros</title>
+    <p>The following macros are defined:</p>
+
+    <list>
+      <item><c>?LOG_EMERGENCY(StringOrReport[,Metadata])</c></item>
+      <item><c>?LOG_EMERGENCY(FunOrFormat,Args[,Metadata])</c></item>
+      <item><c>?LOG_ALERT(StringOrReport[,Metadata])</c></item>
+      <item><c>?LOG_ALERT(FunOrFormat,Args[,Metadata])</c></item>
+      <item><c>?LOG_CRITICAL(StringOrReport[,Metadata])</c></item>
+      <item><c>?LOG_CRITICAL(FunOrFormat,Args[,Metadata])</c></item>
+      <item><c>?LOG_ERROR(StringOrReport[,Metadata])</c></item>
+      <item><c>?LOG_ERROR(FunOrFormat,Args[,Metadata])</c></item>
+      <item><c>?LOG_WARNING(StringOrReport[,Metadata])</c></item>
+      <item><c>?LOG_WARNING(FunOrFormat,Args[,Metadata])</c></item>
+      <item><c>?LOG_NOTICE(StringOrReport[,Metadata])</c></item>
+      <item><c>?LOG_NOTICE(FunOrFormat,Args[,Metadata])</c></item>
+      <item><c>?LOG_INFO(StringOrReport[,Metadata])</c></item>
+      <item><c>?LOG_INFO(FunOrFormat,Args[,Metadata])</c></item>
+      <item><c>?LOG_DEBUG(StringOrReport[,Metadata])</c></item>
+      <item><c>?LOG_DEBUG(FunOrFormat,Args[,Metadata])</c></item>
+    </list>
+
+    <p>All macros expand to a call to logger, where <c>Level</c> is
+      taken from the macro name, and the following metadata is added,
+      or merged with the given <c>Metadata</c>:</p>
+
+    <code>
+#{mfa=>{?MODULE,?FUNCTION_NAME,?FUNCTION_ARITY},
+        file=>?FILE,
+        line=>?LINE}
+    </code>
+
+    <p>The call is wrapped in a case statement and will be evaluated
+      only if <c>Level</c> is equal to or below the configured log
+      level.</p>
+  </section>
+
+  <funcs>
+    <func>
+      <name>emergency(StringOrReport[,Metadata])</name>
+      <name>emergency(Format,Args[,Metadata])</name>
+      <name>emergency(Fun,FunArgs[,Metadata])</name>
+      <fsummary>Logs the given message as level <c>emergency</c>.</fsummary>
+      <desc>
+        <p>Equivalent to
+	<seealso marker="#log-2"><c>log(emergency,...)</c></seealso>.</p>
+      </desc>
+    </func>
+
+    <func>
+      <name>alert(StringOrReport[,Metadata])</name>
+      <name>alert(Format,Args[,Metadata])</name>
+      <name>alert(Fun,FunArgs[,Metadata])</name>
+      <fsummary>Logs the given message as level <c>alert</c>.</fsummary>
+      <desc>
+        <p>Equivalent to
+	<seealso marker="#log-2"><c>log(alert,...)</c></seealso>.</p>
+      </desc>
+    </func>
+
+    <func>
+      <name>critical(StringOrReport[,Metadata])</name>
+      <name>critical(Format,Args[,Metadata])</name>
+      <name>critical(Fun,FunArgs[,Metadata])</name>
+      <fsummary>Logs the given message as level <c>critical</c>.</fsummary>
+      <desc>
+        <p>Equivalent to
+	<seealso marker="#log-2"><c>log(critical,...)</c></seealso>.</p>
+      </desc>
+    </func>
+
+    <func>
+      <name>error(StringOrReport[,Metadata])</name>
+      <name>error(Format,Args[,Metadata])</name>
+      <name>error(Fun,FunArgs[,Metadata])</name>
+      <fsummary>Logs the given message as level <c>error</c>.</fsummary>
+      <desc>
+        <p>Equivalent to
+	<seealso marker="#log-2"><c>log(error,...)</c></seealso>.</p>
+      </desc>
+    </func>
+
+    <func>
+      <name>warning(StringOrReport[,Metadata])</name>
+      <name>warning(Format,Args[,Metadata])</name>
+      <name>warning(Fun,FunArgs[,Metadata])</name>
+      <fsummary>Logs the given message as level <c>warning</c>.</fsummary>
+      <desc>
+        <p>Equivalent to
+	<seealso marker="#log-2"><c>log(warning,...)</c></seealso>.</p>
+      </desc>
+    </func>
+
+    <func>
+      <name>notice(StringOrReport[,Metadata])</name>
+      <name>notice(Format,Args[,Metadata])</name>
+      <name>notice(Fun,FunArgs[,Metadata])</name>
+      <fsummary>Logs the given message as level <c>notice</c>.</fsummary>
+      <desc>
+        <p>Equivalent to
+	<seealso marker="#log-2"><c>log(notice,...)</c></seealso>.</p>
+      </desc>
+    </func>
+
+    <func>
+      <name>info(StringOrReport[,Metadata])</name>
+      <name>info(Format,Args[,Metadata])</name>
+      <name>info(Fun,FunArgs[,Metadata])</name>
+      <fsummary>Logs the given message as level <c>info</c>.</fsummary>
+      <desc>
+        <p>Equivalent to
+	<seealso marker="#log-2"><c>log(info,...)</c></seealso>.</p>
+      </desc>
+    </func>
+
+    <func>
+      <name>debug(StringOrReport[,Metadata])</name>
+      <name>debug(Format,Args[,Metadata])</name>
+      <name>debug(Fun,FunArgs[,Metadata])</name>
+      <fsummary>Logs the given message as level <c>debug</c>.</fsummary>
+      <desc>
+        <p>Equivalent to
+	<seealso marker="#log-2"><c>log(debug,...)</c></seealso>.</p>
+      </desc>
+    </func>
+
+    <func>
+      <name name="log" arity="2"/>
+      <name name="log" arity="3" clause_i="1"/>
+      <name name="log" arity="3" clause_i="2"/>
+      <name name="log" arity="3" clause_i="3"/>
+      <name name="log" arity="4" clause_i="1"/>
+      <name name="log" arity="4" clause_i="2"/>
+      <fsummary>Logs the given message.</fsummary>
+      <type variable="Level"/>
+      <type variable="StringOrReport" name_i="1"/>
+      <type variable="Format" name_i="3"/>
+      <type variable="Args" name_i="3"/>
+      <type variable="Fun" name_i="4"/>
+      <type variable="FunArgs" name_i="4"/>
+      <type variable="Metadata"/>
+      <desc>
+        <p>Log the given message.</p>
+      </desc>
+    </func>
+
+    <func>
+      <name name="get_logger_config" arity="0"/>
+      <fsummary>Lookup the current configuration for logger.</fsummary>
+      <desc>
+        <p>Lookup the current configuration for logger.</p>
+      </desc>
+    </func>
+
+    <func>
+      <name name="get_handler_config" arity="1"/>
+      <fsummary>Lookup the current configuration for the given handler.</fsummary>
+      <desc>
+        <p>Lookup the current configuration for the given handler.</p>
+      </desc>
+    </func>
+
+    <func>
+      <name name="i" arity="0"/>
+      <fsummary>Get information about all logger configurations</fsummary>
+      <desc>
+        <p>Same as <seealso marker="#i/1"><c>logger:i(term)</c></seealso></p>
+      </desc>
+    </func>
+
+    <func>
+      <name name="i" arity="1" clause_i="1"/>
+      <name name="i" arity="1" clause_i="2"/>
+      <name name="i" arity="1" clause_i="3"/>
+      <fsummary>Get information about all logger configurations</fsummary>
+      <desc>
+        <p>The <c>logger:i/1</c> function can be used to get all
+          current logger configuration.  The way that the information
+          is returned depends on the <c><anno>Action</anno></c></p>
+        <taglist>
+          <tag>string</tag>
+          <item>Return the pretty printed current logger configuration
+            as iodata.</item>
+          <tag>term</tag>
+          <item>Return the current logger configuration as a term. The
+            format of this term may change inbetween releases. For a
+            stable format use <seealso marker="#get_handler_config/1">
+	      <c>logger:get_handler_config/1</c></seealso>
+            and <seealso marker="#get_logger_config/0">
+	      <c>logger:get_logger_config/0</c></seealso>.
+            The same as calling <c>logger:i()</c>.</item>
+	  <tag>print</tag>
+          <item>Pretty print all the current logger configuration to
+            standard out. Example:
+            <code><![CDATA[1> logger:i().
+Current logger configuration:
+  Level: info
+  FilterDefault: log
+  Filters:
+  Handlers:
+    Id: logger_std_h
+      Module:    logger_std_h
+      Level:     info
+      Formatter:
+        Module: logger_formatter
+        Config: #{template => [{logger_formatter,header},"\n",msg,"\n"],
+                  legacy_header => true}
+      Filter Default: stop
+      Filters:
+        Id: stop_progress
+          Fun:    fun logger_filters:progress/2
+          Config: stop
+        Id: remote_gl
+          Fun:    fun logger_filters:remote_gl/2
+          Config: stop
+        Id: domain
+          Fun:    fun logger_filters:domain/2
+          Config: {log,prefix_of,[beam,erlang,otp,sasl]}
+        Id: no_domain
+          Fun:    fun logger_filters:domain/2
+          Config: {log,no_domain,[]}
+      Handler Config:
+        logger_std_h: #{type => standard_io}
+  Level set per module:
+    Module: my_module
+      Level:    debug]]></code>
+          </item>
+        </taglist>
+      </desc>
+    </func>
+
+    <func>
+      <name name="add_logger_filter" arity="2"/>
+      <fsummary>Add a filter to the logger.</fsummary>
+      <desc>
+        <p>Add a filter to the logger.</p>
+      </desc>
+    </func>
+
+    <func>
+      <name name="add_handler_filter" arity="3"/>
+      <fsummary>Add a filter to the specified handler.</fsummary>
+      <desc>
+        <p>Add a filter to the specified handler.</p>
+      </desc>
+    </func>
+
+    <func>
+      <name name="remove_logger_filter" arity="1"/>
+      <fsummary>Remove a filter from the logger.</fsummary>
+      <desc>
+        <p>Remove the filter with the specified identity from the logger.</p>
+      </desc>
+    </func>
+
+    <func>
+      <name name="remove_handler_filter" arity="2"/>
+      <fsummary>Remove a filter from the specified handler.</fsummary>
+      <desc>
+        <p>Remove the filter with the specified identity from the given handler.</p>
+      </desc>
+    </func>
+
+    <func>
+      <name name="add_handler" arity="3"/>
+      <fsummary>Add a handler with the given configuration.</fsummary>
+      <desc>
+        <p>Add a handler with the given configuration.</p>
+      </desc>
+    </func>
+
+    <func>
+      <name name="remove_handler" arity="1"/>
+      <fsummary>Remove the handler with the specified identity.</fsummary>
+      <desc>
+        <p>Remove the handler with the specified identity.</p>
+      </desc>
+    </func>
+
+    <func>
+      <name name="set_module_level" arity="2"/>
+      <fsummary>Set the log level for the specified module.</fsummary>
+      <desc>
+        <p>Set the log level for the specified module.</p>
+        <p>To change the logging level globally, use
+        <seealso marker="#set_logger_config/2"><c>logger:set_logger_config(level, Level)</c></seealso>.
+        </p>
+      </desc>
+    </func>
+
+    <func>
+      <name name="reset_module_level" arity="1"/>
+      <fsummary>Remove a module specific log setting.</fsummary>
+      <desc>
+        <p>Remove a module specific log setting. After this, the
+          global log level is used for the specified module.</p>
+      </desc>
+    </func>
+
+    <func>
+      <name name="set_logger_config" arity="1"/>
+      <name name="set_logger_config" arity="2"/>
+      <fsummary>Add or update configuration data for the logger.</fsummary>
+      <desc>
+        <p>Add or update configuration data for the logger.</p>
+      </desc>
+    </func>
+
+    <func>
+      <name name="set_handler_config" arity="2"/>
+      <name name="set_handler_config" arity="3"/>
+      <fsummary>Add or update configuration data for the specified
+        handler.</fsummary>
+      <desc>
+        <p>Add or update configuration data for the specified
+          handler.</p>
+      </desc>
+    </func>
+
+    <func>
+      <name name="compare_levels" arity="2"/>
+      <fsummary>Compare the severity of two log levels.</fsummary>
+      <desc>
+        <p>Compare the severity of two log levels. Returns <c>gt</c>
+          if <c>Level1</c> is more severe than
+          <c>Level2</c>, <c>lt</c> if <c>Level1</c> is less severe,
+          and <c>eq</c> if the levels are equal.</p>
+      </desc>
+    </func>
+
+    <func>
+      <name name="set_process_metadata" arity="1"/>
+      <fsummary>Set metadata to use when logging from current process.</fsummary>
+      <desc>
+        <p>Set metadata which <c>logger</c> automatically inserts it
+          in all log events produced on the current
+          process. Subsequent calls will overwrite previous data set
+          by this function.</p>
+	<p>When logging, location data produced by the log macros,
+	  and/or metadata given as argument to the log call (API
+	  function or macro), will be merged with the process
+	  metadata. If the same keys occur, values from the metadata
+	  argument to the log call will overwrite values in the
+	  process metadata, which in turn will overwrite values from
+	  the location data.</p>
+      </desc>
+    </func>
+
+    <func>
+      <name name="get_process_metadata" arity="0"/>
+      <fsummary>Retrieve data set with set_process_metadata/1.</fsummary>
+      <desc>
+        <p>Retrieve data set
+          with <seealso marker="#set_process_metadata-1">
+	    <c>set_process_metadata/1</c></seealso>.</p>
+      </desc>
+    </func>
+
+    <func>
+      <name name="unset_process_metadata" arity="0"/>
+      <fsummary>Delete data set with set_process_metadata/1.</fsummary>
+      <desc>
+        <p>Delete data set
+          with <seealso marker="#set_process_metadata-1">
+	    <c>set_process_metadata/1</c></seealso>.</p>
+      </desc>
+    </func>
+
+  </funcs>
+
+</erlref>
+
+
diff --git a/lib/kernel/doc/src/logger_arch.png b/lib/kernel/doc/src/logger_arch.png
new file mode 100644
index 0000000000..727609a6ef
--- /dev/null
+++ b/lib/kernel/doc/src/logger_arch.png
diff --git a/lib/kernel/doc/src/logger_chapter.xml b/lib/kernel/doc/src/logger_chapter.xml
new file mode 100644
index 0000000000..2a325453da
--- /dev/null
+++ b/lib/kernel/doc/src/logger_chapter.xml
@@ -0,0 +1,641 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<!DOCTYPE chapter SYSTEM "chapter.dtd">
+
+<chapter>
+  <header>
+    <copyright>
+      <year>2017</year>
+      <holder>Ericsson AB. All Rights Reserved.</holder>
+    </copyright>
+    <legalnotice>
+      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.
+    
+    </legalnotice>
+
+    <title>Logging</title>
+    <prepared></prepared>
+    <docno></docno>
+    <date></date>
+    <rev></rev>
+    <file>logger_chapter.xml</file>
+  </header>
+
+  <section>
+    <title>Overview</title>
+    <p>Erlang/OTP provides a standard API for logging. The backend of
+      this API can be used as is, or it can be customized to suite
+      specific needs.</p>
+    <p>It consists of two parts - the <em>logger</em> part and the
+      <em>handler</em> part. The logger will forward log events to one
+      or more handler(s).</p>
+
+    <image file="logger_arch.png">
+      <icaption>Conceptual overview</icaption>
+    </image>
+
+    <p><em>Filters</em> can be added to the logger and to each
+      handler. The filters decide if an event is to be forwarded or
+      not, and they can also modify all parts of the log event.</p>
+
+    <p>A <em>formatter</em> can be set for each handler. The formatter
+      does the final formatting of the log event, including the log
+      message itself, and possibly a timestamp, header and other
+      metadata.</p>
+
+    <p>In accordance with the Syslog protocol, RFC-5424, eight
+      severity levels can be specified:</p>
+
+    <table align="left">
+      <row>
+	<cell><strong>Level</strong></cell>
+	<cell align="center"><strong>Integer</strong></cell>
+	<cell><strong>Description</strong></cell>
+      </row>
+      <row>
+	<cell>emergency</cell>
+	<cell align="center">0</cell>
+	<cell>system is unusable</cell>
+      </row>
+      <row>
+	<cell>alert</cell>
+	<cell align="center">1</cell>
+	<cell>action must be taken immediately</cell>
+      </row>
+      <row>
+	<cell>critical</cell>
+	<cell align="center">2</cell>
+	<cell>critical contidions</cell>
+      </row>
+      <row>
+	<cell>error</cell>
+	<cell align="center">3</cell>
+	<cell>error conditions</cell>
+      </row>
+      <row>
+	<cell>warning</cell>
+	<cell align="center">4</cell>
+	<cell>warning conditions</cell>
+      </row>
+      <row>
+	<cell>notice</cell>
+	<cell align="center">5</cell>
+	<cell>normal but significant conditions</cell>
+      </row>
+      <row>
+	<cell>info</cell>
+	<cell align="center">6</cell>
+	<cell>informational messages</cell>
+      </row>
+      <row>
+	<cell>debug</cell>
+	<cell align="center">7</cell>
+	<cell>debug-level messages</cell>
+      </row>
+      <tcaption>Severity levels</tcaption>
+    </table>
+
+    <p>A log event is allowed by Logger if the integer value of
+      its <c>Level</c> is less than or equal to the currently
+      configured log level. The log level can be configured globally,
+      or to allow more verbose logging from a specific part of the
+      system, per module.</p>
+
+    <section>
+      <title>Customizable parts</title>
+
+      <taglist>
+	<tag><marker id="Handler"/>Handler</tag>
+	<item>
+	  <p>A handler is defined as a module exporting the following
+	    function:</p>
+
+	  <code>log(Log, Config) -> ok</code>
+
+	  <p>A handler is called by the logger backend after filtering on
+	    logger level and on handler level for the handler which is
+	    about to be called. The function call is done on the client
+	    process, and it is up to the handler implementation if other
+	    processes are to be involved or not.</p>
+
+	  <p>Multiple instances of the same handler can be
+	    added. Configuration is per instance.</p>
+
+	</item>
+
+	<tag><marker id="Filter"/>Filter</tag>
+	<item>
+	  <p>Filters can be set on the logger or on a handler. Logger
+	    filters are applied first, and if passed, the handler filters
+	    for each handler are applied. The handler plugin is only
+	    called if all handler filters for the handler in question also
+	    pass.</p>
+
+	  <p>A filter is specified as:</p>
+
+	  <code>{fun((Log,Extra) -> Log | stop | ignore), Extra}</code>
+
+	  <p>The configuration parameter <c>filter_default</c>
+	    specifies the behavior if all filters return <c>ignore</c>.
+	    <c>filter_default</c> is by default set to <c>log</c>.</p>
+
+	  <p>The <c>Extra</c> parameter may contain any data that the
+	    filter needs.</p>
+	</item>
+
+	<tag><marker id="Formatter"/>Formatter</tag>
+	<item>
+	  <p>A formatter is defined as a module exporting the following
+	    function:</p>
+
+	  <code>format(Log,Extra) -> string()</code>
+
+	  <p>The formatter plugin is called by each handler, and the
+	    returned string can be printed to the handler's destination
+	    (stdout, file, ...).</p>
+	</item>
+
+      </taglist>
+    </section>
+
+    <section>
+      <title>Built-in handlers</title>
+
+      <taglist>
+	<tag><c>logger_std_h</c></tag>
+	<item>
+	  <p>This is the default handler used by OTP. Multiple instances
+	    can be started, and each instance will write log events to a
+	    given destination, console or file. Filters can be used for
+	    selecting which event to send to which handler instance.</p>
+	</item>
+
+	<tag><c>logger_disk_log_h</c></tag>
+	<item>
+	  <p>This handler behaves much like logger_std_h, except it uses
+	    <seealso marker="disk_log"><c>disk_log</c></seealso> as its
+	    destination.</p>
+	</item>
+
+	<tag><marker id="ErrorLoggerManager"/><c>error_logger</c></tag>
+	<item>
+	  <p>This handler is to be used for backwards compatibility
+	    only. It is not started by default, but will be automatically
+	    started the first time an event handler is added
+	    with <seealso marker="error_logger#add_report_handler-1">
+	      <c>error_logger:add_report_handler/1,2</c></seealso>.</p>
+
+	  <p>No built-in event handlers exist.</p>
+	</item>
+      </taglist>
+    </section>
+
+    <section>
+      <title>Built-in filters</title>
+
+      <taglist>
+	<tag><c>logger_filters:domain/2</c></tag>
+	<item>
+	  <p>This filter provides a way of filtering log events based on a
+	    <c>domain</c> field <c>Metadata</c>. See 
+	    <seealso marker="logger_filters#domain-2">
+	    <c>logger_filters:domain/2</c></seealso></p>
+	</item>
+
+	<tag><c>logger_filters:level/2</c></tag>
+	<item>
+	  <p>This filter provides a way of filtering log events based
+	    on the log level. See <seealso marker="logger_filters#domain-2">
+	    <c>logger_filters:domain/2</c></seealso></p>
+	</item>
+
+	<tag><c>logger_filters:progress/2</c></tag>
+	<item>
+	  <p>This filter matches all progress reports
+	    from <c>supervisor</c> and <c>application_controller</c>.
+	    See <seealso marker="logger_filters#progress/2">
+	    <c>logger_filters:progress/2</c></seealso></p>
+	</item>
+
+	<tag><c>logger_filters:remote_gl/2</c></tag>
+	<item>
+	  <p>This filter matches all events originating from a process
+	    that has its group leader on a remote node.
+	    See <seealso marker="logger_filters#remote_gl/2">
+	    <c>logger_filters:remote_gl/2</c></seealso></p>
+	</item>
+      </taglist>
+    </section>
+
+    <section>
+      <title>Default formatter</title>
+
+      <p>The default formatter is <c>logger_formatter</c>.
+	See <seealso marker="logger_formatter#format-2">
+	  <c>logger_formatter:format/2</c></seealso>.</p>
+    </section>
+  </section>
+
+  <section>
+    <title>Configuration</title>
+
+    <section>
+      <title>Application environment variables</title>
+      <p>See <seealso marker="kernel_app#configuration">Kernel(6)</seealso> for
+	information about the application environment variables that can
+	be used for configuring logger.</p>
+    </section>
+
+    <section>
+      <title>Logger configuration</title>
+
+      <taglist>
+	<tag><c>level</c></tag>
+	<item>
+	  <p>Specifies the severity level to log.</p>
+	</item>
+	<tag><c>filters</c></tag>
+	<item>
+	  <p>Logger filters are added or removed with
+	    <seealso marker="logger#add_logger_filter-2">
+	      <c>logger:add_logger_filter/2</c></seealso> and
+	    <seealso marker="logger#remove_logger_filter-1">
+	      <c>logger:remove_logger_filter/1</c></seealso>,
+	    respectively.</p>
+	  <p>See <seealso marker="#Filter">Filter</seealso> for more
+	    information.</p>
+	  <p>By default, no filters exist.</p>
+	</item>
+	<tag><c>filter_default = log | stop</c></tag>
+	<item>
+	  <p>Specifies what to do with an event if all filters
+	    return <c>ignore</c>.</p>
+	  <p>Default is <c>log</c>.</p>
+	</item>
+	<tag><c>handlers</c></tag>
+	<item>
+	  <p>Handlers are added or removed with
+	    <seealso marker="logger#add_handler-3">
+	      <c>logger:add_handler/3</c></seealso> and
+	    <seealso marker="logger#remove_handler-1">
+	      <c>logger:remove_handler/1</c></seealso>,
+	    respectively.</p>
+	  <p>See <seealso marker="#Handler">Handler</seealso> for more
+	    information.</p>
+	</item>
+      </taglist>
+    </section>
+
+    <section>
+      <title>Handler configuration</title>
+      <taglist>
+	<tag><c>level</c></tag>
+	<item>
+	  <p>Specifies the severity level to log.</p>
+	</item>
+	<tag><c>filters</c></tag>
+	<item>
+	  <p>Handler filters can be specified when adding the handler,
+	    or added or removed later with
+	    <seealso marker="logger#add_handler_filter-3">
+	      <c>logger:add_handler_filter/3</c></seealso> and
+	    <seealso marker="logger#remove_handler_filter-2">
+	      <c>logger:remove_handler_filter/2</c></seealso>,
+	    respectively.</p>
+	  <p>See <seealso marker="#Filter">Filter</seealso> for more
+	    information.</p>
+	  <p>By default, no filters exist.</p>
+	</item>
+	<tag><c>filter_default = log | stop</c></tag>
+	<item>
+	  <p>Specifies what to do with an event if all filters
+	    return <c>ignore</c>.</p>
+	  <p>Default is <c>log</c>.</p>
+	</item>
+        <tag><c>depth = pos_integer() | unlimited</c></tag>
+	<item>
+	  <p>Specifies if the depth of terms in the log events shall
+	    be limited by using control characters <c>~P</c>
+	    and <c>~W</c> instead of <c>~p</c> and <c>~w</c>,
+	    respectively. See
+	    <seealso marker="stdlib:io#format-1"><c>io:format</c></seealso>.</p>
+	</item>
+        <tag><c>max_size = pos_integer() | unlimited</c></tag>
+	<item>
+	  <p>Specifies if the size of a log event shall be limited by
+	    truncating the formatted string.</p>
+	</item>
+	<tag><c>formatter = {Module::module(),Extra::term()}</c></tag>
+	<item>
+	  <p>See <seealso marker="#Formatter">Formatter</seealso> for more
+	    information.</p>
+	  <p>The default module is <seealso marker="logger_formatter">
+	      <c>logger_formatter</c></seealso>, and <c>Extra</c> is
+	      it's configuration map.</p>
+	</item>
+      </taglist>
+
+      <p>Note that <c>level</c> and <c>filters</c> are obeyed by
+	Logger itself before forwarding the log events to each
+	handler, while <c>depth</c>, <c>max_size</c>
+	and <c>formatter</c> are left to the handler
+	implementation. All Logger's built-in handlers do apply these
+	configuration parameters before printing.</p>
+    </section>
+
+  </section>
+
+  <section>
+    <marker id="compatibility"/>
+    <title>Backwards compatibility with error_logger</title>
+    <p>Logger provides backwards compatibility with the old
+      <c>error_logger</c> in the following ways:</p>
+
+    <taglist>
+      <tag>Legacy event handlers</tag>
+      <item>
+	<p>To use event handlers written for <c>error_logger</c>, just
+	  add your event handler with</p>
+	<code>
+error_logger:add_report_handler/1,2.
+	</code>
+	<p>This will automatically start the <c>error_logger</c>
+	  event manager, and add <c>error_logger</c> as a
+	  handler to <c>logger</c>, with configuration</p>
+<code>
+#{level=>info,
+  filter_default=>log,
+  filters=>[]}.
+</code>
+	<p>Note that this handler will ignore events that do not
+	  originate from the old <c>error_logger</c> API, or from
+	  within OTP. This means that if your code uses the logger API
+	  for logging, then your log events will be discarded by this
+	  handler.</p>
+	<p>Also note that <c>error_logger</c> is not overload
+	  protected.</p>
+      </item>
+      <tag>Logger API</tag>
+      <item>
+	<p>The old <c>error_logger</c> API still exists, but should
+	  only be used by legacy code. It will be removed in a later
+	  release.</p>
+      </item>
+      <tag>Output format</tag>
+      <item>
+	<p>To get log events on the same format as produced
+	  by <c>error_logger_tty_h</c> and <c>error_logger_file_h</c>,
+	  use the default formatter, <c>logger_formatter</c>, with
+	  configuration parameter <c>legacy_header=>true</c>. This is
+	  also the default.</p>
+      </item>
+      <tag>Default format of log events from OTP</tag>
+      <item>
+	<p>By default, all log events originating from within OTP,
+	  except the former so called "SASL reports", look the same as
+	  before.</p>
+      </item>
+      <tag>SASL reports</tag>
+      <item>
+	<p>By SASL reports we mean supervisor reports, crash reports
+	  and progress reports.</p>
+	<p>In earlier releases, these reports were only logged when
+	  the SASL application was running, and they were printed
+	  trough specific event handlers
+	  named <c>sasl_report_tty_h</c>
+	  and <c>sasl_report_file_h</c>.</p>
+	<p>The destination of these log events were configured by
+	  environment variables for the SASL application.</p>
+	<p>Due to the specific event handlers, the output format
+	  slightly differed from other log events.</p>
+	<p>As of OTP-21, the concept of SASL reports is removed,
+	  meaning that the default behavior is as follows:</p>
+	<list>
+	  <item>Supervisor reports, crash reports and progress reports
+	    are no longer connected to the SASL application.</item>
+	  <item>Supervisor reports and crash reports are logged by
+	    default.</item>
+	  <item>Progress reports are not logged by default, but can be
+	    enabled with the kernel environment
+	    variable <c>logger_log_progress</c>.</item>
+	  <item>The output format is the same for all log
+	    events.</item>
+	</list>
+	<p>If the old behavior is preferred, the kernel environment
+	  variable <c>logger_sasl_compatible</c> can be set
+	  to <c>true</c>. The old SASL environment variables can then
+	  be used as before, and the SASL reports will only be printed
+	  if the SASL application is running - through a second log
+	  handler named <c>sasl_h</c>.</p>
+	<p>All SASL reports have a metadata
+	  field <c>domain=>[beam,erlang,otp,sasl]</c>, which can be
+	  used, for example, by filters to to stop or allow the
+	  events.</p>
+      </item>
+    </taglist>
+  </section>
+
+
+  <section>
+    <title>Error handling</title>
+    <p>Log data is expected to be either a format string and
+      arguments, a string (unicode:chardata), or a report (map or
+      key-value list) which can be converted to a format string and
+      arguments by the handler. A default report callback should be
+      included in the log event's metadata, which can be used for
+      converting the report to a format string and arguments. The
+      handler might also do a custom conversion if the default format
+      is not desired.</p>
+    <p><c>logger</c> does, to a certain extent, check its input data
+      before forwarding a log event to the handlers, but it does not
+      evaluate conversion funs or check the validity of format strings
+      and arguments. This means that any filter or handler must be
+      careful when formatting the data of a log event, making sure
+      that it does not crash due to bad input data or faulty
+      callbacks.</p>
+    <p>If a filter or handler still crashes, logger will remove the
+      filter or handler in question from the configuration, and then
+      print a short error message on the console. A debug event
+      containing the crash reason and other details is also issued,
+      and can be seen if a handler is installed which logs on debug
+      level.</p>
+  </section>
+
+  <section>
+    <title>Example: add a handler to log debug events to file</title>
+    <p>When starting an erlang node, the default behavior is that all
+      log events with level info and above are logged to the
+      console. In order to also log debug events, you can either
+      change the global log level to <c>debug</c> or add a separate
+      handler to take care of this. In this example we will add a new
+      handler which prints the debug events to a separate file.</p>
+    <p>First, we add an instance of logger_std_h with
+      type <c>{file,File}</c>, and we set the handler's level
+      to <c>debug</c>:</p>
+    <pre>
+1> <input>Config = #{level=>debug,logger_std_h=>#{type=>{file,"./debug.log"}}}.</input>
+#{logger_std_h => #{type => {file,"./debug.log"}},
+  level => debug}
+2> <input>logger:add_handler(debug_handler,logger_std_h,Config).</input>
+ok</pre>
+    <p>By default, the handler receives all events, so we need to add a filter
+      to stop all non-debug events:</p>
+    <pre>
+3> <input>Fun = fun(#{level:=debug}=Log,_) -> Log; (_,_) -> stop end.</input>
+#Fun&lt;erl_eval.12.98642416>
+4> <input>logger:add_handler_filter(debug_handler,allow_debug,{Fun,[]}).</input>
+ok</pre>
+    <p>And finally, we need to make sure that the logger itself allows
+      debug events. This can either be done by setting the global
+      logger level:</p>
+    <pre>
+5> <input>logger:set_logger_config(level,debug).</input>
+ok</pre>
+    <p>Or by allowing debug events from one or a few modules only:</p>
+    <pre>
+6> <input>logger:set_module_level(mymodule,debug).</input>
+ok</pre>
+
+  </section>
+
+  <section>
+    <title>Example: implement a handler</title>
+    <p>The only requirement that a handler MUST fulfill is to export
+      the following function:</p>
+    <code>log(logger:log(),logger:config()) ->ok</code>
+    <p>It may also implement the following callbacks:</p>
+    <code>
+adding_handler(logger:handler_id(),logger:config()) -> {ok,logger:config()} | {error,term()}
+removing_handler(logger:handler_id()) -> ok
+changing_config(logger:handler_id(),logger:config(),logger:config()) -> {ok,logger:config()} | {error,term()}
+    </code>
+    <p>When logger:add_handler(Id,Module,Config) is called, logger
+      will first call Module:adding_handler(Id,Config), and if it
+      returns {ok,NewConfig} the NewConfig is written to the
+      configuration database. After this, the handler may receive log
+      events as calls to Module:log/2.</p>
+    <p>A handler can be removed by calling
+      logger:remove_handler(Id). logger will call
+      Module:removing_handler(Id), and then remove the handler's
+      configuration from the configuration database.</p>
+    <p>When logger:set_handler_config is called, logger calls
+      Module:changing_config(Id,OldConfig,NewConfig). If this function
+      returns ok, the NewConfig is written to the configuration
+      database.</p>
+
+    <p>A simple handler which prints to the console could be
+      implemented as follows:</p>
+    <code>
+-module(myhandler).
+-export([log/2]).
+
+log(#{msg:={report,R}},_) ->
+    io:format("~p~n",[R]);
+log(#{msg:={string,S}},_) ->
+    io:put_chars(S);
+log(#{msg:={F,A}},_) ->
+    io:format(F,A).
+    </code>
+
+    <p>A simple handler which prints to file could be implemented like
+      this:</p>
+    <code>
+-module(myhandler).
+-export([adding_handler/2, removing_handler/1, log/2]).
+-export([init/1, handle_call/3, handle_cast/2, terminate/2]).
+
+adding_handler(Id,Config) ->
+    {ok,Fd} = file:open(File,[append,{encoding,utf8}]),
+    {ok,Config#{myhandler_fd=>Fd}}.
+
+removing_handler(Id,#{myhandler_fd:=Fd}) ->
+    _ = file:close(Fd),
+    ok.
+
+log(#{msg:={report,R}},#{myhandler_fd:=Fd}) ->
+    io:format(Fd,"~p~n",[R]);
+log(#{msg:={string,S}},#{myhandler_fd:=Fd}) ->
+    io:put_chars(Fd,S);
+log(#{msg:={F,A}},#{myhandler_fd:=Fd}) ->
+    io:format(Fd,F,A).
+    </code>
+
+    <p>Note that none of the above handlers have any overload
+      protection, and all log events are printed directly from the
+      client process. Neither do the handlers use the formatter or
+      in any way add time or other metadata to the printed events.</p>
+
+    <p>For examples of overload protection, please refer to the
+      implementation
+      of <seealso marker="logger_std_h"><c>logger_std_h</c></seealso>
+      and <!--<seealso marker="logger_disk_log_h"--><c>logger_disk_log_h</c>
+      <!--/seealso-->.</p>
+
+    <p>Below is a simpler example of a handler which logs through one
+      single process, and uses the default formatter to gain a common
+      look of the log events.</p>
+    <p>It also uses the metadata field <c>report_cb</c>, if it exists,
+      to print reports in the way the event issuer suggests. The
+      formatter will normally do this, but if the handler either has
+      an own default (as in this example) or if the
+      given <c>report_cb</c> should not be used at all, then the
+      handler must take care of this itself.</p>
+    <code>
+-module(myhandler).
+-export([adding_handler/2, removing_handler/1, log/2]).
+-export([init/1, handle_call/3, handle_cast/2, terminate/2]).
+
+adding_handler(Id,Config) ->
+    {ok,Pid} = gen_server:start(?MODULE,Config),
+    {ok,Config#{myhandler_pid=>Pid}}.
+
+removing_handler(Id,#{myhandler_pid:=Pid}) ->
+    gen_server:stop(Pid).
+
+log(Log,#{myhandler_pid:=Pid} = Config) ->
+    gen_server:cast(Pid,{log,Log,Config}).
+
+init(#{myhandler_file:=File}) ->
+    {ok,Fd} = file:open(File,[append,{encoding,utf8}]),
+    {ok,#{file=>File,fd=>Fd}}.
+
+handle_call(_,_,State) ->
+    {reply,{error,bad_request},State}.
+
+handle_cast({log,Log,Config},#{fd:=Fd} = State) ->
+    do_log(Fd,Log,Config),
+    {noreply,State}.
+
+terminate(Reason,#{fd:=Fd}) ->
+    _ = file:close(Fd),
+    ok.
+
+do_log(Fd,#{msg:={report,R}} = Log, Config) ->
+    Fun = maps:get(report_cb,Config,fun my_report_cb/1,
+    {F,A} = Fun(R),
+    do_log(Fd,Log#{msg=>{F,A},Config);
+do_log(Fd,Log,#{formatter:={FModule,FConfig}}) ->
+    String = FModule:format(Log,FConfig),
+    io:put_chars(Fd,String).
+
+my_report_cb(R) ->
+    {"~p",[R]}.
+    </code>
+  </section>
+
+
+  <section>
+    <title>See Also</title>
+    <p><seealso marker="error_logger"><c>error_logger(3)</c></seealso>,
+    <seealso marker="sasl:sasl_app"><c>SASL(6)</c></seealso></p>
+  </section>
+</chapter>
diff --git a/lib/kernel/doc/src/logger_filters.xml b/lib/kernel/doc/src/logger_filters.xml
new file mode 100644
index 0000000000..d742391e35
--- /dev/null
+++ b/lib/kernel/doc/src/logger_filters.xml
@@ -0,0 +1,191 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<!DOCTYPE erlref SYSTEM "erlref.dtd">
+
+<erlref>
+  <header>
+    <copyright>
+      <year>2018</year>
+      <holder>Ericsson AB. All Rights Reserved.</holder>
+    </copyright>
+    <legalnotice>
+      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.
+
+    </legalnotice>
+
+    <title>logger_filters</title>
+    <prepared></prepared>
+    <responsible></responsible>
+    <docno></docno>
+    <approved></approved>
+    <checked></checked>
+    <date></date>
+    <rev>A</rev>
+    <file>logger_filters.xml</file>
+  </header>
+  <module>logger_filters</module>
+  <modulesummary>Filters to use with logger.</modulesummary>
+
+  <description>
+    <p>Filters to use with logger. All functions exported from this
+      module can be used as logger or handler
+      filters. See <seealso marker="logger#add_logger_filter-2">
+	<c>logger:add_logger_filter/2</c></seealso>
+      and <seealso marker="logger#add_handler_filter-3">
+	<c>logger:add_handler_filter/3</c></seealso>
+      for more information about how filters are added.</p>
+  </description>
+
+  <funcs>
+    <func>
+      <name name="domain" arity="2"/>
+      <fsummary>Filter log events based on the domain field in metadata.</fsummary>
+      <desc>
+	  <p>This filter provides a way of filtering log events based on a
+	    <c>domain</c> field <c>Metadata</c>.</p>
+
+	  <p>The <c><anno>Extra</anno></c> parameter is specified when
+	    adding the filter
+	    via <seealso marker="logger#add_logger_filter-2">
+	      <c>logger:add_logger_filter/2</c></seealso>
+	    or <seealso marker="logger#add_handler_filter-3">
+	      <c>logger:add_handler_filter/3</c></seealso>.</p>
+
+	  <p>The filter compares the value of the <c>domain</c> field
+	    in the log event's metadata (<c>Domain</c>)
+	    to <c><anno>MatchDomain</anno></c> as follows:</p>
+
+	  <taglist>
+	    <tag><c><anno>Compare</anno> = starts_with</c></tag>
+	    <item><p>The filter matches if <c>MatchDomain</c> is a prefix
+	      of <c>Domain</c>.</p></item>
+	    <tag><c><anno>Compare</anno> = prefix_of</c></tag>
+	    <item><p>The filter matches if <c>Domain</c> is a prefix
+	      of <c>MatchDomain</c>.</p></item>
+	    <tag><c><anno>Compare</anno> = equals</c></tag>
+	    <item><p>The filter matches if <c>Domain</c> is equal
+	      to <c>MatchDomain</c>.</p></item>
+	    <tag><c><anno>Compare</anno> = no_domain</c></tag>
+	    <item><p>The filter matches if there is no domain field in
+	      metadata. In this case <c><anno>MatchDomain</anno></c> shall
+	      be <c>[]</c>.</p></item>
+	  </taglist>
+
+          <p>If the filter matches and <c><anno>Action</anno> =
+            log</c>, the log event is allowed. If the filter matches
+            and <c><anno>Action</anno> = stop</c>, the log event is
+            stopped.</p>
+
+	  <p>If the filter does not match, it returns <c>ignore</c>,
+	    meaning that other filters, or the value of the
+	    configuration parameter <c>filter_default</c>, will decide
+	    if the event is allowed or not.</p>
+
+	  <p>Log events that do not contain any domain field, will
+	    only match when <c><anno>Compare</anno> = no_domain</c>.</p>
+
+	  <p>Example: stop all events with
+	    domain <c>[beam,erlang,otp,sasl|_]</c></p>
+
+	  <code>
+logger:set_handler_config(h1,filter_default,log). % this is the default
+Filter = {fun logger_filters:domain/2,{stop,starts_with,[beam,erlang,otp,sasl]}}.
+logger:add_handler_filter(h1,no_sasl,Filter).
+ok</code>
+      </desc>
+    </func>
+
+    <func>
+      <name name="level" arity="2"/>
+      <fsummary>Filter log events based on the log level.</fsummary>
+      <desc>
+	  <p>This filter provides a way of filtering log events based
+	    on the log level. It matches log events by comparing the
+	    log level with a predefined <c>MatchLevel</c></p>
+
+	  <p>The <c><anno>Extra</anno></c> parameter is specified when
+	    adding the filter
+	    via <seealso marker="logger#add_logger_filter-2">
+	      <c>logger:add_logger_filter/2</c></seealso>
+	    or <seealso marker="logger#add_handler_filter-3">
+	      <c>logger:add_handler_filter/3</c></seealso>.</p>
+
+	  <p>The filter compares the value of the event's log level
+	    (<c>Level</c>) to <c><anno>MatchLevel</anno></c> by
+	    calling <seealso marker="logger#compare_levels-2">
+	      <c>logger:compare_levels(Level,MatchLevel) -> CmpRet</c></seealso>. It
+	    matches the event if:</p>
+
+	  <list>
+	    <item><c>CmpRet = eq</c> and <c><anno>Operator</anno> =
+		eq | lteq | gteq</c></item>
+	    <item><c>CmpRet = lt</c> and <c><anno>Operator</anno> =
+		lt | lteq | neq</c></item>
+	    <item><c>CmpRet = gt</c> and <c><anno>Operator</anno> =
+		gt | gteq | neq</c></item>
+	  </list>
+
+          <p>If the filter matches and <c><anno>Action</anno> =
+            log</c>, the log event is allowed. If the filter matches
+            and <c><anno>Action</anno> = stop</c>, the log event is
+            stopped.</p>
+
+	  <p>If the filter does not match, it returns <c>ignore</c>,
+	    meaning that other filters, or the value of the
+	    configuration parameter <c>filter_default</c>, will decide
+	    if the event is allowed or not.</p>
+
+	  <p>Example: only allow debug level log events</p>
+
+	  <code>
+logger:set_handler_config(h1,filter_default,stop).
+Filter = {fun logger_filters:level/2,{log,eq,debug}}.
+logger:add_handler_filter(h1,debug_only,Filter).
+ok</code>
+      </desc>
+    </func>
+
+    <func>
+      <name name="progress" arity="2"/>
+      <fsummary>Filter progress reports from supervisor and application_controller.</fsummary>
+      <desc>
+	  <p>This filter matches all progress reports
+	    from <c>supervisor</c> and <c>application_controller</c>.</p>
+
+	  <p>If <c><anno>Extra</anno> = log</c>, the progress reports
+	    are allowed. If <c><anno>Extra</anno> = stop</c>, the
+	    progress reports are stopped.</p>
+
+	  <p>The filter returns <c>ignore</c> for all other log events.</p>
+      </desc>
+    </func>
+
+    <func>
+      <name name="remote_gl" arity="2"/>
+      <fsummary>Filter events with group leader on remote node.</fsummary>
+      <desc>
+	  <p>This filter matches all events originating from a process
+	    that has its group leader on a remote node.</p>
+
+	  <p>If <c><anno>Extra</anno> = log</c>, the matching events
+	    are allowed. If <c><anno>Extra</anno> = stop</c>, the
+	    matching events are stopped.</p>
+
+	  <p>The filter returns <c>ignore</c> for all other log events.</p>
+      </desc>
+    </func>
+
+  </funcs>
+
+</erlref>
+
+
diff --git a/lib/kernel/doc/src/logger_formatter.xml b/lib/kernel/doc/src/logger_formatter.xml
new file mode 100644
index 0000000000..213a592e47
--- /dev/null
+++ b/lib/kernel/doc/src/logger_formatter.xml
@@ -0,0 +1,149 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<!DOCTYPE erlref SYSTEM "erlref.dtd">
+
+<erlref>
+  <header>
+    <copyright>
+      <year>2017</year>
+      <holder>Ericsson AB. All Rights Reserved.</holder>
+    </copyright>
+    <legalnotice>
+      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.
+
+    </legalnotice>
+
+    <title>logger_formatter</title>
+    <prepared></prepared>
+    <responsible></responsible>
+    <docno></docno>
+    <approved></approved>
+    <checked></checked>
+    <date></date>
+    <rev>A</rev>
+    <file>logger_formatter.xml</file>
+  </header>
+  <module>logger_formatter</module>
+  <modulesummary>Default formatter for the Logger application.</modulesummary>
+
+  <description>
+    <p>Default formatter for the Logger application.</p>
+  </description>
+
+  <datatypes>
+    <datatype>
+      <name name="template"/>
+      <desc>
+      </desc>
+    </datatype>
+  </datatypes>
+
+  <funcs>
+    <func>
+      <name name="format" arity="2"/>
+      <fsummary>Formats the given message.</fsummary>
+      <desc>
+        <p>Formats the given message.</p>
+	<p>The template is a list of atoms, tuples and strings. Atoms
+	  can be <c>level</c> or <c>msg</c>, which are placeholders
+	  for the severity level and the log message,
+	  repectively. Tuples are interpreted as placeholders for
+	  metadata. Each element in the tuple must be an atom which
+	  matches a key in the nested metadata map, e.g. the
+	  tuple <c>{key1,key2}</c> will be replaced by the value of
+	  the key2 field in this nested map (the value vill be
+	  converted to a string):</p>
+
+<code>
+#{key1=>#{key2=>my_value,
+          ...},
+  ...}</code>
+
+
+        <p> Strings are printed literally.</p>
+
+	<p><c>depth</c> is a positive integer representing the maximum
+	  depth to which terms shall be printed by this
+	  formatter. Format strings passed to this formatter are
+	  rewritten. The format controls ~p and ~w are replaced with
+	  ~P and ~W, respectively, and the value is used as the depth
+	  parameter. For details, see
+	  <seealso marker="stdlib:io#format-2">io:format/2</seealso>
+	  in STDLIB.</p>
+
+	<p><c>max_size</c> is a positive integer representing the
+	  maximum size a string returned from this formatter can
+	  have. If the formatted string is longer, it will be
+	  truncated.</p>
+
+	<p><c>utc</c> is a boolean. If set to true, all dates are
+	  displayed in Universal Coordinated Time. Default
+	  is <c>false</c>.</p>
+
+	<p><c>report_cb</c> must be a function with arity 1,
+	  returning <c>{Format,Args}</c>. This function will replace
+	  any <c>report_cb</c> found in metadata.</p>
+
+	<p>If <c>single_line=true</c>, all newlines in the message are
+	  replaced with <c>", "</c>, and whitespaces following directly
+	  after newlines are removed. Note that newlines added by the
+	  formatter template are not replaced.</p>
+
+	<p>If <c>legacy_header=true</c> a header field is added to
+	  logger_formatter's part of <c>Metadata</c>. The value of
+	  this field is a string similar to the header created by the
+	  old <c>error_logger</c> event handlers. It can be included
+	  in the log event by adding the
+	  tuple <c>{logger_formatter,header}</c> to the template.</p>
+
+	<p>The default template when <c>legacy_header=true</c> is</p>
+
+	<code>[{logger_formatter,header},"\n",msg,"\n"]</code>
+
+	<p>which will cause log entries like this:</p>
+
+	<code>=ERROR REPORT==== 29-Dec-2017::13:30:51.245123 ===
+    process: &lt;0.74.0&gt;
+    exit_reason: "Something went wrong"</code>
+
+	<p>Note that all eight levels might occur here, not
+	  only <c>ERROR</c>, <c>WARNING</c> or <c>INFO</c>. And also
+	  that micro seconds are added at the end of the
+	  timestamp.</p>
+
+	<p>The default template when <c>single_line=true</c> is</p>
+
+	<code>[time," ",level,": ",msg,"\n"]</code>
+
+	<p>which will cause log entries like this:</p>
+
+	<code>2017-12-29 13:31:49.640317 error: process: &lt;0.74.0&gt;, exit_reason: "Something went wrong"</code>
+
+	<p>The default template when both <c>legacy_header</c> and
+	  <c>single_line</c> are set to false is:</p>
+
+	<code>[time," ",level,":\n",msg,"\n"]</code>
+
+	<p>which will cause log entries like this:</p>
+
+	<code>2017-12-29 13:32:25.191925 error:
+    process: &lt;0.74.0&gt;
+    exit_reason: "Something went wrong"</code>
+
+      </desc>
+    </func>
+
+  </funcs>
+
+</erlref>
+
+
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 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<!DOCTYPE erlref SYSTEM "erlref.dtd">
+
+<erlref>
+  <header>
+    <copyright>
+      <year>2017</year>
+      <holder>Ericsson AB. All Rights Reserved.</holder>
+    </copyright>
+    <legalnotice>
+      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.
+
+    </legalnotice>
+
+    <title>logger_std_h</title>
+    <prepared></prepared>
+    <responsible></responsible>
+    <docno></docno>
+    <approved></approved>
+    <checked></checked>
+    <date></date>
+    <rev>A</rev>
+    <file>logger_std_h.xml</file>
+  </header>
+  <module>logger_std_h</module>
+  <modulesummary>Default handler for the Logger application.</modulesummary>
+
+  <description>
+    <p>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 <c>standard_io</c>,
+      <c>standard_error</c> or to a file.</p>
+
+    <p>To add a new instance,
+      use <seealso marker="logger#add_handler-3"><c>logger:add_handler/3</c>
+      </seealso>.</p>
+
+    <p>The handler configuration may contain the following keys,
+      associated with values as described:</p>
+    <taglist>
+      <tag><c>filters</c></tag>
+      <item>
+	<p>A list of <c>{Id,{Fun,Args}}</c>, each representing a filter
+	  that may selct or modify log events to forward to this
+	  handler.</p></item>
+      <tag><c>filter_default</c></tag>
+      <item>
+	<p>The atom <c>log</c> or <c>stop</c>, specifying what to
+	  do with a log event if all filters
+	  return <c>ignore</c>.</p></item>
+      <tag><c>formatter</c></tag>
+      <item>
+	<p><c>{Module,Extra}</c>,
+	  where <c>Module:format(Log,Extra)</c> will be called by
+	  the handler to produce the string that will be printed to
+	  the handler's destination.</p></item>
+      <tag><c>level</c></tag>
+      <item>
+	<p>The level of log events that <c>logger</c> shall forward to
+	  this handler. Log events of the specified, or more severe
+	  levels, are forwarded.</p></item>
+    </taglist>
+
+  </description>
+
+<!--  <funcs>
+  </funcs> -->
+
+</erlref>
+
+
diff --git a/lib/kernel/doc/src/part.xml b/lib/kernel/doc/src/part.xml
new file mode 100644
index 0000000000..68eb4530e2
--- /dev/null
+++ b/lib/kernel/doc/src/part.xml
@@ -0,0 +1,40 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<!DOCTYPE part SYSTEM "part.dtd">
+
+<part xmlns:xi="http://www.w3.org/2001/XInclude">
+  <header>
+    <copyright>
+      <year>1996</year><year>2017</year>
+      <holder>Ericsson AB. All Rights Reserved.</holder>
+    </copyright>
+    <legalnotice>
+      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.
+    
+    </legalnotice>
+
+    <title>Logger User's Guide</title>
+    <prepared>OTP Team</prepared>
+    <docno></docno>
+    <date>2017-12-01</date>
+    <rev>0.1</rev>
+    <file>part.xml</file>
+  </header>
+  <description>
+    <p>The System Architecture Support Libraries SASL application
+      provides support for alarm handling, release handling, and
+      related functions.</p>
+  </description>
+  <xi:include href="introduction_chapter.xml"/>
+  <xi:include href="logger_chapter.xml"/>
+</part>
+
diff --git a/lib/kernel/doc/src/ref_man.xml b/lib/kernel/doc/src/ref_man.xml
index 5cd77e0f6f..7f4d5b384f 100644
--- a/lib/kernel/doc/src/ref_man.xml
+++ b/lib/kernel/doc/src/ref_man.xml
@@ -52,6 +52,10 @@
   <xi:include href="inet.xml"/>
   <xi:include href="inet_res.xml"/>
   <xi:include href="init_stub.xml"/>
+  <xi:include href="logger.xml"/>
+  <xi:include href="logger_filters.xml"/>
+  <xi:include href="logger_formatter.xml"/>
+  <xi:include href="logger_std_h.xml"/>
   <xi:include href="net_adm.xml"/>
   <xi:include href="net_kernel.xml"/>
   <xi:include href="os.xml"/>
diff --git a/lib/kernel/doc/src/specs.xml b/lib/kernel/doc/src/specs.xml
index 29d52f23bb..a67e26ef16 100644
--- a/lib/kernel/doc/src/specs.xml
+++ b/lib/kernel/doc/src/specs.xml
@@ -20,6 +20,10 @@
   <xi:include href="../specs/specs_inet.xml"/>
   <xi:include href="../specs/specs_inet_res.xml"/>
   <xi:include href="../specs/specs_init_stub.xml"/>
+  <xi:include href="../specs/specs_logger.xml"/>
+  <xi:include href="../specs/specs_logger_filters.xml"/>
+  <xi:include href="../specs/specs_logger_formatter.xml"/>
+  <xi:include href="../specs/specs_logger_std_h.xml"/>
   <xi:include href="../specs/specs_net_adm.xml"/>
   <xi:include href="../specs/specs_net_kernel.xml"/>
   <xi:include href="../specs/specs_os.xml"/>