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-rw-r--r--lib/kernel/doc/src/logger.xml61
-rw-r--r--lib/kernel/doc/src/logger_chapter.xml55
2 files changed, 112 insertions, 4 deletions
diff --git a/lib/kernel/doc/src/logger.xml b/lib/kernel/doc/src/logger.xml
index e09c5db5e3..0668676096 100644
--- a/lib/kernel/doc/src/logger.xml
+++ b/lib/kernel/doc/src/logger.xml
@@ -245,6 +245,12 @@ logger:error("error happened because: ~p", [Reason]). % Without macro
</desc>
</datatype>
<datatype>
+ <name name="olp_config"/>
+ <desc>
+ <p></p>
+ </desc>
+ </datatype>
+ <datatype>
<name name="primary_config"/>
<desc>
<p>Primary configuration data for Logger. The following
@@ -597,8 +603,8 @@ start(_, []) ->
<name name="get_config" arity="0" since="OTP 21.0"/>
<fsummary>Look up the current Logger configuration</fsummary>
<desc>
- <p>Look up all current Logger configuration, including primary
- and handler configuration, and module level settings.</p>
+ <p>Look up all current Logger configuration, including primary,
+ handler, and proxy configuration, and module level settings.</p>
</desc>
</func>
@@ -636,6 +642,17 @@ start(_, []) ->
</func>
<func>
+ <name name="get_proxy_config" arity="0" since="OTP 21.3"/>
+ <fsummary>Look up the current configuration for the Logger proxy.</fsummary>
+ <desc>
+ <p>Look up the current configuration for the Logger proxy.</p>
+ <p>For more information about the proxy, see
+ section <seealso marker="logger_chapter#proxy">Logger
+ Proxy</seealso> in the Kernel User's Guide.</p>
+ </desc>
+ </func>
+
+ <func>
<name name="get_module_level" arity="0" since="OTP 21.0"/>
<fsummary>Look up all current module levels.</fsummary>
<desc>
@@ -801,6 +818,27 @@ start(_, []) ->
</func>
<func>
+ <name name="set_proxy_config" arity="1" since="OTP 21.3"/>
+ <fsummary>Set configuration data for the Logger proxy.</fsummary>
+ <desc>
+ <p>Set configuration data for the Logger proxy. This
+ overwrites the current proxy configuration. Keys that are not
+ specified in the <c><anno>Config</anno></c> map gets default
+ values.</p>
+ <p>To modify the existing configuration,
+ use <seealso marker="#update_proxy_config-1">
+ <c>update_proxy_config/1</c></seealso>, or, if a more
+ complex merge is needed, read the current configuration
+ with <seealso marker="#get_proxy_config-0"><c>get_proxy_config/0</c>
+ </seealso>, then do the merge before writing the new
+ configuration back with this function.</p>
+ <p>For more information about the proxy, see
+ section <seealso marker="logger_chapter#proxy">Logger
+ Proxy</seealso> in the Kernel User's Guide.</p>
+ </desc>
+ </func>
+
+ <func>
<name name="set_module_level" arity="2" since="OTP 21.0"/>
<fsummary>Set the log level for the specified modules.</fsummary>
<desc>
@@ -1013,6 +1051,25 @@ logger:set_process_metadata(maps:merge(logger:get_process_metadata(), Meta)).
</seealso>.</p>
</desc>
</func>
+
+ <func>
+ <name name="update_proxy_config" arity="1" since="OTP 21.3"/>
+ <fsummary>Update configuration data for the Logger proxy.</fsummary>
+ <desc>
+ <p>Update configuration data for the Logger proxy. This function
+ behaves as if it was implemented as follows:</p>
+ <code type="erl">
+Old = logger:get_proxy_config(),
+logger:set_proxy_config(maps:merge(Old, Config)).
+ </code>
+ <p>To overwrite the existing configuration without any merge,
+ use <seealso marker="#set_proxy_config-1"><c>set_proxy_config/1</c>
+ </seealso>.</p>
+ <p>For more information about the proxy, see
+ section <seealso marker="logger_chapter#proxy">Logger
+ Proxy</seealso> in the Kernel User's Guide.</p>
+ </desc>
+ </func>
</funcs>
<section>
diff --git a/lib/kernel/doc/src/logger_chapter.xml b/lib/kernel/doc/src/logger_chapter.xml
index c7e87e6668..03b9edcf8f 100644
--- a/lib/kernel/doc/src/logger_chapter.xml
+++ b/lib/kernel/doc/src/logger_chapter.xml
@@ -693,8 +693,10 @@ logger:debug(#{got => connection_request, id => Id, state => State},
with <seealso marker="#logger_sasl_compatible">
<c>logger_sasl_compatible</c></seealso>.</p>
<p>With this parameter, you can modify or disable the default
- handler, add custom handlers and primary logger filters, and
- set log levels per module.</p>
+ handler, add custom handlers and primary logger filters, set
+ log levels per module, and modify
+ the <seealso marker="#proxy">proxy</seealso>
+ configuration.</p>
<p><c>Config</c> is any (zero or more) of the following:</p>
<taglist>
<tag><c>{handler, default, undefined}</c></tag>
@@ -746,6 +748,14 @@ logger:debug(#{got => connection_request, id => Id, state => State},
<p>for each <c>Module</c>.</p>
<p>Multiple entries of this type are allowed.</p>
</item>
+ <tag><c>{proxy, ProxyConfig}</c></tag>
+ <item>
+ <p>Sets the proxy configuration, equivalent to calling</p>
+ <pre><seealso marker="logger#set_proxy_config/1">
+ logger:set_proxy_config(ProxyConfig)
+ </seealso></pre>
+ <p>Only one entry of this type is allowed.</p>
+ </item>
</taglist>
<p>See
section <seealso marker="#config_examples">Configuration
@@ -1334,9 +1344,50 @@ logger:add_handler(my_disk_log_h, logger_disk_log_h,
</section>
<section>
+ <marker id="proxy"/>
+ <title>Logger Proxy</title>
+ <p>The Logger proxy is an Erlang process which is part of the
+ Kernel application's supervision tree. During startup, the proxy
+ process registers itself as the <c>system_logger</c>, meaning
+ that log events produced by the emulator are sent to this
+ process.</p>
+ <p>When a log event is issued on a process which has its group
+ leader on a remote node, Logger automatically forwards the log
+ event to the group leader's node. To achieve this, it first
+ sends the log event as an Erlang message from the original
+ client process to the proxy on the local node, and the proxy in
+ turn forwards the event to the proxy on the remote node.</p>
+ <p>When receiving a log event, either from the emulator or from a
+ remote node, the proxy calls the Logger API to log the event.</p>
+ <p>The proxy process is overload protected in the same way as
+ described in
+ section <seealso marker="#overload_protection">Protecting the
+ Handler from Overload</seealso>, but with the following default
+ values:</p>
+ <code>
+ #{sync_mode_qlen => 500,
+ drop_mode_qlen => 1000,
+ flush_qlen => 5000,
+ burst_limit_enable => false,
+ overload_kill_enable => false}</code>
+ <p>For log events from the emulator, synchronous message passing
+ mode is not applicable, since all messages are passed
+ asynchronously by the emulator. Drop mode is achieved by setting
+ the <c>system_logger</c> to <c>undefined</c>, forcing the
+ emulator to drop events until it is set back to the proxy pid
+ again.</p>
+ <p>The proxy uses <seealso marker="erts:erlang#send_nosuspend/2">
+ <c>erlang:send_nosuspend/2</c></seealso> when sending log
+ events to a remote node. If the message could not be sent
+ without suspending the sender, it is dropped. This is to avoid
+ blocking the proxy process.</p>
+ </section>
+
+ <section>
<title>See Also</title>
<p>
<seealso marker="disk_log"><c>disk_log(3)</c></seealso>,
+ <seealso marker="erts:erlang"><c>erlang(3)</c></seealso>,
<seealso marker="error_logger"><c>error_logger(3)</c></seealso>,
<seealso marker="logger"><c>logger(3)</c></seealso>,
<seealso marker="logger_disk_log_h"><c>logger_disk_log_h(3)</c></seealso>,