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Diffstat (limited to 'lib/kernel/doc/src/logger.xml')
| -rw-r--r-- | lib/kernel/doc/src/logger.xml | 720 |
1 files changed, 646 insertions, 74 deletions
diff --git a/lib/kernel/doc/src/logger.xml b/lib/kernel/doc/src/logger.xml index 66e6e5c689..911eb158da 100644 --- a/lib/kernel/doc/src/logger.xml +++ b/lib/kernel/doc/src/logger.xml @@ -33,10 +33,50 @@ <file>logger.xml</file> </header> <module>logger</module> - <modulesummary>API module for the logger application.</modulesummary> + <modulesummary>API module for logging in Erlang/OTP.</modulesummary> <description> - + <p> + This module is the main API for logging in Erlang/OTP. It + contains functions that allow applications to use a single log + API and the system to manage those log events independently. Use + the <seealso marker="#emergency-1">API functions</seealso> or the log + <seealso marker="#macros">macros</seealso> to log events. For instance, + to log a new error event:</p> + <code> +?LOG_ERROR("error happened because: ~p",[Reason]). %% With macro +logger:error("error happened because: ~p",[Reason]). %% Without macro + </code> + <p>This log event is then sent to the configured log handlers which + by default means that it is be printed to the console. If you want + your systems logs to be printed to a file instead of the console you + must configure the default handler to do so. The simplest way is + to include the following in your <seealso marker="config"><c>sys.config</c></seealso>.</p> + <code> +[{kernel, + [{logger, + [{handler,default,logger_std_h, + #{logger_std_h=>#{type=>{file,"path/to/file.log"}}}}]}]}]. + </code> + <p> + For more information about: + </p> + <list type="bulleted"> + <item>how to use the API, + see <seealso marker="logger_chapter">the User's Guide</seealso>.</item> + <item>how to configure Logger, + see the <seealso marker="logger_chapter#configuration">Configuration</seealso> + section in the User's Guide.</item> + <item>the convinience macros in logger.hrl, + see <seealso marker="#macros">the macro section</seealso>.</item> + <item>what the builtin formatter can do, + see <seealso marker="logger_formatter">logger_formatter</seealso>.</item> + <item>what the builtin handlers can do, + see <seealso marker="logger_std_h">logger_std_h</seealso> and + <seealso marker="logger_disk_log_h">logger_disk_log_h</seealso>.</item> + <item>what builtin filters are available, + see <seealso marker="logger_filters">logger_filters</seealso>.</item> + </list> </description> <datatypes> @@ -47,7 +87,7 @@ </desc> </datatype> <datatype> - <name name="log"/> + <name name="log_event"/> <desc> <p></p> </desc> @@ -67,37 +107,119 @@ <datatype> <name name="metadata"/> <desc> - <p>Metadata associated with the message to be logged.</p> + <p>Metadata for the log event.</p> + <p>Logger adds the following metadata to each log event:</p> + <list> + <item><c>pid => self()</c></item> + <item><c>gl => group_leader()</c></item> + <item><c>time => erlang:system_time(microsecond)</c></item> + </list> + <p>When a log macro is used, Logger also inserts location + information:</p> + <list> + <item><c>mfa => {?MODULE,?FUNCTION_NAME,?FUNCTION_ARITY}</c></item> + <item><c>file => ?FILE</c></item> + <item><c>line => ?LINE</c></item> + </list> + <p>You can add custom metadata, either by specifying a map as + the last parameter to any of the log macros or the API + functions, or by setting process metadata + with <seealso marker="#set_process_metadata-1"> + <c>set_process_metadata/1</c></seealso> + or <seealso marker="#update_process_metadata-1"> + <c>update_process_metadata/1</c></seealso>.</p> + <p>Logger merges all the metadata maps before forwarding the + log event to the handlers. If the same keys occur, values + from the log call overwrite process metadata, which in turn + overwrite values set by Logger.</p> + <p>The following custom metadata keys have special meaning:</p> + <taglist> + <tag><c>domain</c></tag> + <item> + <p>The value associated with this key is used by filters + for grouping log events originating from, for example, + specific functional + areas. See <seealso marker="logger_filters#domain-2"> + <c>logger_filters:domain/2</c></seealso> + for a description of how this field can be used.</p> + </item> + <tag><c>report_cb</c></tag> + <item> + <p>If the log message is specified as + a <seealso marker="#type-report"><c>report()</c></seealso>, + the <c>report_cb</c> key can be associated with a fun + (report callback) that converts the report to a format + string and arguments. See + section <seealso marker="logger_chapter#log_message">Log + Message</seealso> in the User's Guide for more + information about report callbacks.</p> + </item> + </taglist> </desc> </datatype> <datatype> <name name="config"/> <desc> - <p></p> + <p>Configuration data for the logger part of Logger, or for a handler.</p> + <p>The following default values apply:</p> + <list> + <item><c>level => info</c></item> + <item><c>filter_default => log</c></item> + <item><c>filters => []</c></item> + <item><c>formatter => {logger_formatter,DefaultFormatterConfig</c>}</item> + </list> + <p>See the <seealso marker="logger_formatter#type-config"> + <c>logger_formatter(3)</c></seealso> manual page for + information about the default configuration for this + formatter.</p> </desc> </datatype> <datatype> <name name="handler_id"/> <desc> - <p></p> + <p>A unique identifier for a handler instance.</p> </desc> </datatype> <datatype> <name name="filter_id"/> <desc> - <p></p> + <p>A unique identifier for a filter.</p> </desc> </datatype> <datatype> <name name="filter"/> <desc> - <p></p> + <p>A filter which can be installed for the logger part of + Logger, or for a handler.</p> + </desc> + </datatype> + <datatype> + <name name="filter_arg"/> + <desc> + <p>The second argument to the filter fun.</p> </desc> </datatype> <datatype> <name name="filter_return"/> <desc> - <p></p> + <p>The return value from the filter fun.</p> + </desc> + </datatype> + <datatype> + <name name="timestamp"/> + <desc> + <p>A timestamp produced + with <seealso marker="erts:erlang#system_time-1"> + <c>erlang:system_time(microsecond)</c></seealso>.</p> + </desc> + </datatype> + <datatype> + <name name="formatter_config"/> + <desc> + <p>Configuration data for the + formatter. See <seealso marker="logger_formatter"> + <c>logger_formatter(3)</c></seealso> + for an example of a formatter implementation.</p> </desc> </datatype> </datatypes> @@ -125,15 +247,11 @@ <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>All macros expand to a call to Logger, where <c>Level</c> is + taken from the macro name, and location data is added to the + metadata. See the description of + the <seealso marker="#type-metadata"><c>metadata()</c></seealso> + type for more information about the location data.</p> <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 @@ -251,23 +369,26 @@ <func> <name name="get_logger_config" arity="0"/> - <fsummary>Lookup the current configuration for logger.</fsummary> + <fsummary>Look up the current configuration for the logger part + of Logger.</fsummary> <desc> - <p>Lookup the current configuration for logger.</p> + <p>Look up the current configuration for the logger part of + Logger.</p> </desc> </func> <func> <name name="get_handler_config" arity="1"/> - <fsummary>Lookup the current configuration for the given handler.</fsummary> + <fsummary>Look up the current configuration for the given + handler.</fsummary> <desc> - <p>Lookup the current configuration for the given handler.</p> + <p>Look up the current configuration for the given handler.</p> </desc> </func> <func> <name name="i" arity="0"/> - <fsummary>Get information about all logger configurations</fsummary> + <fsummary>Get all Logger configurations</fsummary> <desc> <p>Same as <seealso marker="#i/1"><c>logger:i(term)</c></seealso></p> </desc> @@ -277,39 +398,42 @@ <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> + <fsummary>Get 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> + <p>Display or return all current Logger configurations.</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"> + <tag><c><anno>Action</anno> = string</c></tag> + <item> + <p>Return the pretty printed current Logger configuration + as iodata.</p> + </item> + <tag><c><anno>Action</anno> = term</c></tag> + <item> + <p>Return the current Logger configuration as a term. The + format of this term may change between 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(). + and <seealso marker="#get_logger_config/0"> + <c>logger:get_logger_config/0</c></seealso>.</p> + <p>The same as calling <c>logger:i()</c>.</p> + </item> + <tag><c><anno>Action</anno> = print</c></tag> + <item> + <p>Pretty print all the current Logger configuration to + standard out. Example:</p> + <code><![CDATA[1> logger:i(print). Current logger configuration: Level: info - FilterDefault: log + Filter Default: log Filters: Handlers: - Id: logger_std_h + Id: default Module: logger_std_h Level: info Formatter: Module: logger_formatter - Config: #{template => [{logger_formatter,header},"\n",msg,"\n"], - legacy_header => true} + Config: #{legacy_header => true,single_line => false, + template => [{logger_formatter,header},"\n",msg,"\n"]} Filter Default: stop Filters: Id: stop_progress @@ -320,10 +444,10 @@ Current logger configuration: Config: stop Id: domain Fun: fun logger_filters:domain/2 - Config: {log,prefix_of,[beam,erlang,otp,sasl]} + Config: {log,super,[beam,erlang,otp,sasl]} Id: no_domain Fun: fun logger_filters:domain/2 - Config: {log,no_domain,[]} + Config: {log,undefined,[]} Handler Config: logger_std_h: #{type => standard_io} Level set per module: @@ -336,9 +460,42 @@ Current logger configuration: <func> <name name="add_logger_filter" arity="2"/> - <fsummary>Add a filter to the logger.</fsummary> + <fsummary>Add a filter to the logger part of Logger.</fsummary> <desc> - <p>Add a filter to the logger.</p> + <p>Add a filter to the logger part of Logger.</p> + <p>The filter fun is called with the log event as the first + parameter, and the specified <c>filter_args()</c> as the + second parameter.</p> + <p>The return value of the fun specifies if a log event is to + be discarded or forwarded to the handlers:</p> + <taglist> + <tag><c>log_event()</c></tag> + <item> + <p>The filter <em>passed</em>. The next logger filter, if + any, is applied. If no more logger filters exist, the + log event is forwarded to the handler part of Logger, + where handler filters are applied.</p> + </item> + <tag><c>stop</c></tag> + <item> + <p>The filter <em>did not pass</em>, and the log event is + immediately discarded.</p> + </item> + <tag><c>ignore</c></tag> + <item> + <p>The filter has no knowledge of the log event. The next + logger filter, if any, is applied. If no more logger + filters exist, the value of the <c>filter_default</c> + configuration parameter for the logger part specifies if + the log event shall be discarded or forwarded to the + handler part.</p> + </item> + </taglist> + <p>See section <seealso marker="logger_chapter#filters"> + Filters</seealso> in the User's Guide for more information + about filters.</p> + <p>Some built-in filters exist. These are defined + in <seealso marker="logger_filters"><c>logger_filters</c></seealso>.</p> </desc> </func> @@ -347,14 +504,48 @@ Current logger configuration: <fsummary>Add a filter to the specified handler.</fsummary> <desc> <p>Add a filter to the specified handler.</p> + <p>The filter fun is called with the log event as the first + parameter, and the specified <c>filter_args()</c> as the + second parameter.</p> + <p>The return value of the fun specifies if a log event is to + be discarded or forwarded to the handler callback:</p> + <taglist> + <tag><c>log_event()</c></tag> + <item> + <p>The filter <em>passed</em>. The next handler filter, if + any, is applied. If no more filters exist for this + handler, the log event is forwarded to the handler + callback.</p> + </item> + <tag><c>stop</c></tag> + <item> + <p>The filter <em>did not pass</em>, and the log event is + immediately discarded.</p> + </item> + <tag><c>ignore</c></tag> + <item> + <p>The filter has no knowledge of the log event. The next + handler filter, if any, is applied. If no more filters + exist for this handler, the value of + the <c>filter_default</c> configuration parameter for + the handler specifies if the log event shall be + discarded or forwarded to the handler callback.</p> + </item> + </taglist> + <p>See + section <seealso marker="logger_chapter#filters">Filters</seealso> + in the User's Guide for more information about filters.</p> + <p>Some built-in filters exist. These are defined in + <seealso marker="logger_filters"><c>logger_filters</c></seealso>.</p> </desc> </func> <func> <name name="remove_logger_filter" arity="1"/> - <fsummary>Remove a filter from the logger.</fsummary> + <fsummary>Remove a filter from the logger part of Logger.</fsummary> <desc> - <p>Remove the filter with the specified identity from the logger.</p> + <p>Remove the filter identified + by <c><anno>FilterId</anno></c> from the logger part of Logger.</p> </desc> </func> @@ -362,7 +553,9 @@ Current logger configuration: <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> + <p>Remove the filter identified + by <c><anno>FilterId</anno></c> from the handler identified + by <c><anno>HandlerId</anno></c>.</p> </desc> </func> @@ -371,6 +564,9 @@ Current logger configuration: <fsummary>Add a handler with the given configuration.</fsummary> <desc> <p>Add a handler with the given configuration.</p> + <p><c><anno>HandlerId</anno></c> is a unique identifier which + must be used in all subsequent calls referring to this + handler.</p> </desc> </func> @@ -378,7 +574,7 @@ Current logger configuration: <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> + <p>Remove the handler identified by <c><anno>HandlerId</anno></c>.</p> </desc> </func> @@ -386,15 +582,43 @@ Current logger configuration: <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> + <p>Set the log level for the + specified <c><anno>Module</anno></c>.</p> + <p>The log level for a module overrides the global log level + of Logger for log events originating from the module in + question. Notice, however, that it does not override the + level configuration for any handler.</p> + <p>For example: Assume that the global log level for Logger + is <c>info</c>, and there is one handler, <c>h1</c>, with + level <c>info</c> and one handler, <c>h2</c>, with + level <c>debug</c>.</p> + <p>With this configuration, no debug messages will be logged, + since they are all stopped by the global log level.</p> + <p>If the level for <c>mymodule</c> is now set + to <c>debug</c>, then debug events from this module will be + logged by the handler <c>h2</c>, but not by + handler <c>h1</c>.</p> + <p>Debug events from other modules are still not logged.</p> + <p>To change the global log level for Logger, use + <seealso marker="#set_logger_config/2"> + <c>logger:set_logger_config(level,Level)</c></seealso>.</p> + <p>To change the log level for a handler, use + <seealso marker="#set_handler_config/3"> + <c>logger:set_handler_config(HandlerId,level,Level)</c></seealso>.</p> + <note> + <p>The originating module for a log event is only detected + if <c>mfa=>{Module,Function,Arity}</c> exists in the + metadata. When log macros are used, this association is + automatically added to all log events. If an API function + is called directly, without using a macro, the logging + client must explicitly add this information if module + levels shall have any effect.</p> + </note> </desc> </func> <func> - <name name="reset_module_level" arity="1"/> + <name name="unset_module_level" arity="1"/> <fsummary>Remove a module specific log setting.</fsummary> <desc> <p>Remove a module specific log setting. After this, the @@ -403,22 +627,179 @@ Current logger configuration: </func> <func> + <name name="add_handlers" arity="1" clause_i="1"/> + <fsummary>Set up log handlers from the application's + configuration parameters.</fsummary> + <desc> + <p>Reads the application configuration parameter <c>logger</c> and + calls <c>logger:add_handlers/1</c> with its contents.</p> + </desc> + </func> + + <func> + <name name="add_handlers" arity="1" clause_i="2"/> + <fsummary>Setup logger handlers.</fsummary> + <type name="config_handler"/> + <desc> + <p>This function should be used by custom Logger handlers to make + configuration consistent no matter which handler the system uses. + Normal usage is to add a call to <c>logger:add_handlers/1</c> + just after the processes that the handler needs are started, + and pass the application's <c>logger</c> configuration as the argument. + For example:</p> + <code> +-behaviour(application). +start(_, []) -> + case supervisor:start_link({local, my_sup}, my_sup, []) of + {ok, Pid} -> + ok = logger:add_handlers(my_app), + {ok, Pid, []}; + Error -> Error + end.</code> + <p>This reads the <c>logger</c> configuration parameter from + the <c>my_all</c> application and starts the configured + handlers. The contents of the configuration use the same + rules as the + <seealso marker="logger_chapter#handler-configuration">logger handler configuration</seealso>. + </p> + <p>If the handler is meant to replace the default handler, the Kernel's + default handler have to be disabled before the new handler is added. + A <c>sys.config</c> file that disables the Kernel handler and adds + a custom handler could look like this:</p> + <code> +[{kernel, + [{logger, + %% Disable the default Kernel handler + [{handler,default,undefined}]}]}, + {my_app, + [{logger, + %% Enable this handler as the default + [{handler,default,my_handler,#{}}]}]}]. + </code> + </desc> + </func> + + <func> <name name="set_logger_config" arity="1"/> + <fsummary>Set configuration data for the logger part of Logger.</fsummary> + <desc> + <p>Set configuration data for the logger part of Logger. This + overwrites the current logger configuration.</p> + <p>To modify the existing configuration, + use <seealso marker="#update_logger_config-1"> + <c>update_logger_config/1</c></seealso>, or, if a more + complex merge is needed, read the current configuration + with <seealso marker="#get_logger_config-0"><c>get_logger_config/0</c> + </seealso>, then do the merge before writing the new + configuration back with this function.</p> + <p>If a key is removed compared to the current configuration, + the default value is used.</p> + </desc> + </func> + + <func> <name name="set_logger_config" arity="2"/> - <fsummary>Add or update configuration data for the logger.</fsummary> + <fsummary>Add or update configuration data for the logger part + of Logger.</fsummary> <desc> - <p>Add or update configuration data for the logger.</p> + <p>Add or update configuration data for the logger part of + Logger. If the given <c><anno>Key</anno></c> already exists, + its associated value will be changed + to <c><anno>Value</anno></c>. If it does not exist, it will + be added.</p> + </desc> + </func> + + <func> + <name name="update_logger_config" arity="1"/> + <fsummary>Update configuration data for the logger part of + Logger.</fsummary> + <desc> + <p>Update configuration data for the logger part of + Logger. This function behaves as if it was implemented as + follows:</p> + <code type="erl"> +{ok,Old} = logger:get_logger_config(), +logger:set_logger_config(maps:merge(Old,Config)). + </code> + <p>To overwrite the existing configuration without any merge, + use <seealso marker="#set_logger_config-1"><c>set_logger_config/1</c> + </seealso>.</p> </desc> </func> <func> <name name="set_handler_config" arity="2"/> + <fsummary>Set configuration data for the specified handler.</fsummary> + <desc> + <p>Set configuration data for the specified handler. This + overwrites the current handler configuration.</p> + <p>To modify the existing configuration, + use <seealso marker="#update_handler_config-2"> + <c>update_handler_config/2</c></seealso>, or, if a more + complex merge is needed, read the current configuration + with <seealso marker="#get_handler_config-1"><c>get_handler_config/1</c> + </seealso>, then do the merge before writing the new + configuration back with this function.</p> + <p>If a key is removed compared to the current configuration, + and the key is known by Logger, the default value is used. If + it is a custom key, then it is up to the handler + implementation if the value is removed or a default value is + inserted.</p> + </desc> + </func> + + <func> <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> + handler. If the given <c><anno>Key</anno></c> already + exists, its associated value will be changed + to <c><anno>Value</anno></c>. If it does not exist, it will + be added.</p> + </desc> + </func> + + <func> + <name name="update_handler_config" arity="2"/> + <fsummary>Update configuration data for the specified handler.</fsummary> + <desc> + <p>Update configuration data for the specified handler. This function + behaves as if it was implemented as follows:</p> + <code type="erl"> +{ok,{_,Old}} = logger:get_handler_config(HandlerId), +logger:set_handler_config(HandlerId,maps:merge(Old,Config)). + </code> + <p>To overwrite the existing configuration without any merge, + use <seealso marker="#set_handler_config-2"><c>set_handler_config/2</c> + </seealso>.</p> + </desc> + </func> + + <func> + <name name="update_formatter_config" arity="2"/> + <fsummary>Update the formatter configuration for the specified handler.</fsummary> + <desc> + <p>Update the formatter configuration for the specified handler.</p> + <p>The new configuration is merged with the existing formatter + configuration.</p> + <p>To overwrite the existing configuration without any merge, + use <seealso marker="#set_handler_config-3"> + <c>set_handler_config(HandlerId,formatter, + {FormatterModule,FormatterConfig})</c></seealso>.</p> + </desc> + </func> + + <func> + <name name="update_formatter_config" arity="3"/> + <fsummary>Update the formatter configuration for the specified handler.</fsummary> + <desc> + <p>Update the formatter configuration for the specified handler.</p> + <p>This is equivalent + to <br/><seealso marker="#update_formatter_config-2"> + <c>update_formatter_config(<anno>HandlerId</anno>,#{<anno>Key</anno>=><anno>Value</anno>})</c></seealso></p> </desc> </func> @@ -437,17 +818,37 @@ Current logger configuration: <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> + <p>Set metadata which Logger shall automatically insert in + all log events produced on the current process.</p> + <p>Location data produced by the log macros, and/or metadata + given as argument to the log call (API function or macro), + are merged with the process metadata. If the same keys + occur, values from the metadata argument to the log call + overwrite values from the process metadata, which in turn + overwrite values from the location data.</p> + <p>Subsequent calls to this function overwrites previous data + set. To update existing data instead of overwriting it, + see <seealso marker="#update_process_metadata-1"> + <c>update_process_metadata/1</c></seealso>.</p> + </desc> + </func> + + <func> + <name name="update_process_metadata" arity="1"/> + <fsummary>Set or update metadata to use when logging from + current process.</fsummary> + <desc> + <p>Set or update metadata to use when logging from current + process</p> + <p>If process metadata exists for the current process, this + function behaves as if it was implemented as follows:</p> + <code type="erl"> +logger:set_process_metadata(maps:merge(logger:get_process_metadata(),Meta)). + </code> + <p>If no process metadata exists, the function behaves as + <seealso marker="#set_process_metadata-1"> + <c>set_process_metadata/1</c> + </seealso>.</p> </desc> </func> @@ -457,7 +858,9 @@ Current logger configuration: <desc> <p>Retrieve data set with <seealso marker="#set_process_metadata-1"> - <c>set_process_metadata/1</c></seealso>.</p> + <c>set_process_metadata/1</c></seealso> or + <seealso marker="#update_process_metadata-1"> + <c>update_process_metadata/1</c></seealso>.</p> </desc> </func> @@ -467,12 +870,181 @@ Current logger configuration: <desc> <p>Delete data set with <seealso marker="#set_process_metadata-1"> - <c>set_process_metadata/1</c></seealso>.</p> + <c>set_process_metadata/1</c></seealso> or + <seealso marker="#update_process_metadata-1"> + <c>update_process_metadata/1</c></seealso>.</p> + </desc> + </func> + + <func> + <name name="format_report" arity="1"/> + <fsummary>Convert a log message on report form to {Format,Args}.</fsummary> + <desc> + <p>Convert a log message on report form to <c>{Format,Args}</c>.</p> + <p>This is the default report callback used + by <seealso marker="logger_formatter"> + <c>logger_formatter</c></seealso> when no custom report + callback is found.</p> + <p>The function produces lines of <c>Key: Value</c> from + key-value lists. Strings are printed with <c>~ts</c> and + other terms with <c>~tp</c>.</p> + <p>If the <c><anno>Report</anno></c> is a map, it is + converted to a key-value list before formatting as such.</p> + </desc> + </func> + + </funcs> + + <section> + <marker id="handler_callback_functions"/> + <title>Handler Callback Functions</title> + <p>The following functions are to be exported from a handler + callback module.</p> + </section> + + <funcs> + <func> + <name>HModule:adding_handler(Config1) -> {ok,Config2} | {error,Reason}</name> + <fsummary>An instance of this handler is about to be added.</fsummary> + <type> + <v>Config1 = Config2 = + <seealso marker="#type-config">config()</seealso></v> + <v>Reason = term()</v> + </type> + <desc> + <p>This callback function is optional.</p> + <p>The function is called when an new handler is about to be + added, and the purpose is to verify the configuration and + initiate all resources needed by the handler.</p> + <p>The handler identity is associated with the <c>id</c> key + in <c>Config1</c>.</p> + <p>If everything succeeds, the callback function can add + possible default values or internal state values to the + configuration, and return the adjusted map + in <c>{ok,Config2}</c>.</p> + <p>If the configuration is faulty, or if the initiation fails, + the callback function must return <c>{error,Reason}</c>.</p> + </desc> + </func> + + <func> + <name>HModule:changing_config(Config1,Config2) -> {ok,Config3} | {error,Reason}</name> + <fsummary>The configuration for this handler is about to change.</fsummary> + <type> + <v>Config1 = Config2 = Config3 = + <seealso marker="#type-config">config()</seealso></v> + <v>Reason = term()</v> + </type> + <desc> + <p>This callback function is optional.</p> + <p>The function is called when the configuration for a handler + is about to change, and the purpose is to verify and act on + the new configuration.</p> + <p><c>Config1</c> is the existing configuration + and <c>Config2</c> is the new configuration.</p> + <p>The handler identity is associated with the <c>id</c> key + in <c>Config1</c>.</p> + <p>If everything succeeds, the callback function must return a + possibly adjusted configuration in <c>{ok,Config3}</c>.</p> + <p>If the configuration is faulty, the callback function must + return <c>{error,Reason}</c>.</p> + </desc> + </func> + + <func> + <name>HModule:log(LogEvent,Config) -> void()</name> + <fsummary>Log the given log event.</fsummary> + <type> + <v>LogEvent = + <seealso marker="#type-log_event">log_event()</seealso></v> + <v>Config = + <seealso marker="#type-config">config()</seealso></v> + </type> + <desc> + <p>This callback function is mandatory.</p> + <p>The function is called when all global filters and all + handler filters for the handler in question have passed for + the given log event.</p> + <p>The handler identity is associated with the <c>id</c> key + in <c>Config</c>.</p> + <p>The handler must log the event.</p> + <p>The return value from this function is ignored by + Logger.</p> + </desc> + </func> + + <func> + <name>HModule:removing_handler(Config) -> ok</name> + <fsummary>The given handler is about to be removed.</fsummary> + <type> + <v>Config = + <seealso marker="#type-config">config()</seealso></v> + </type> + <desc> + <p>This callback function is optional.</p> + <p>The function is called when a handler is about to be + removed, and the purpose is to release all resources used by + the handler.</p> + <p>The handler identity is associated with the <c>id</c> key + in <c>Config</c>.</p> + <p>The return value is ignored by Logger.</p> </desc> </func> </funcs> + <section> + <marker id="formatter_callback_functions"/> + <title>Formatter Callback Functions</title> + <p>The following functions are to be exported from a formatter + callback module.</p> + </section> + + <funcs> + <func> + <name>FModule:check_config(FConfig) -> ok | {error,term()}</name> + <fsummary>Validate the given formatter configuration.</fsummary> + <type> + <v>FConfig = + <seealso marker="#type-formatter_config">formatter_config()</seealso></v> + </type> + <desc> + <p>This callback function is optional.</p> + <p>The function is called by a Logger when formatter + configuration is set or modified. The formatter must + validate the given configuration and return <c>ok</c> if it + is correct, and <c>{error,term()}</c> if it is faulty.</p> + <p>See <seealso marker="logger_formatter"> + <c>logger_formatter(3)</c></seealso> + for an example implementation. <c>logger_formatter</c> is the + default formatter used by Logger.</p> + </desc> + </func> + <func> + <name>FModule:format(LogEvent,FConfig) -> FormattedLogEntry</name> + <fsummary>Format the given log event.</fsummary> + <type> + <v>LogEvent = + <seealso marker="#type-log_event">log_event()</seealso></v> + <v>FConfig = + <seealso marker="#type-formatter_config">formatter_config()</seealso></v> + <v>FormattedLogEntry = + <seealso marker="unicode#type-chardata">unicode:chardata()</seealso></v> + </type> + <desc> + <p>This callback function is mandatory.</p> + <p>The function can be called by a log handler to convert a + log event term to a printable string. The returned value + can, for example, be printed as a log entry to the console + or a file using <seealso marker="stdlib:io#put_chars-1"> + <c>io:put_chars/1,2</c></seealso>.</p> + <p>See <seealso marker="logger_formatter"> + <c>logger_formatter(3)</c></seealso> + for an example implementation. <c>logger_formatter</c> is the + default formatter used by Logger.</p> + </desc> + </func> + </funcs> </erlref> |