diff options
Diffstat (limited to 'lib/kernel/doc/src/logger_std_h.xml')
| -rw-r--r-- | lib/kernel/doc/src/logger_std_h.xml | 130 |
1 files changed, 103 insertions, 27 deletions
diff --git a/lib/kernel/doc/src/logger_std_h.xml b/lib/kernel/doc/src/logger_std_h.xml index e156f5719b..5ac4f58d12 100644 --- a/lib/kernel/doc/src/logger_std_h.xml +++ b/lib/kernel/doc/src/logger_std_h.xml @@ -32,7 +32,7 @@ <rev>A</rev> <file>logger_std_h.xml</file> </header> - <module>logger_std_h</module> + <module since="OTP 21.0">logger_std_h</module> <modulesummary>Standard handler for Logger.</modulesummary> <description> @@ -55,30 +55,105 @@ is stored in a sub map with the key <c>config</c>, and can contain the following parameters:</p> <taglist> - <tag><marker id="type"/><c>type</c></tag> + <tag><marker id="type"/><c>type = standard_io | standard_error | file</c></tag> <item> - <p>This has the value <c>standard_io</c>, <c>standard_error</c>, - <c>{file,LogFileName}</c>, or <c>{file,LogFileName,LogFileOpts}</c>.</p> - <p>If <c>LogFileOpts</c> is specified, it replaces the default - list of options used when opening the log file. The default - list is <c>[raw,append,delayed_write]</c>. One reason to do - so can be to change <c>append</c> to, for - example, <c>write</c>, ensuring that the old log is - truncated when a node is restarted. See the reference manual - for <seealso marker="file#open-2"><c>file:open/2</c></seealso> - for more information about file options.</p> - <p>Log files are always UTF-8 encoded. The encoding can not be - changed by setting the option <c>{encoding,Encoding}</c> - in <c>LogFileOpts</c>.</p> - <p>Notice that the standard handler does not have support for - circular logging. Use the disk_log handler, - <seealso marker="logger_disk_log_h"><c>logger_disk_log_h</c></seealso>, - for this.</p> - <p>The value is set when the handler is added, and it can not + <p>Specifies the log destination.</p> + <p>The value is set when the handler is added, and it cannot be changed in runtime.</p> - <p>Defaults to <c>standard_io</c>.</p> + <p>Defaults to <c>standard_io</c>, unless + parameter <seealso marker="#file"><c>file</c></seealso> is + given, in which case it defaults to <c>file</c>.</p> </item> - <tag><c>filesync_repeat_interval</c></tag> + <tag><marker id="file"/><c>file = </c><seealso marker="file#type-filename"><c>file:filename()</c></seealso></tag> + <item> + <p>This specifies the name of the log file when the handler is + of type <c>file</c>.</p> + <p>The value is set when the handler is added, and it cannot + be changed in runtime.</p> + <p>Defaults to the same name as the handler identity, in the + current directory.</p> + </item> + <tag><marker id="modes"/><c>modes = [</c><seealso marker="file#type-mode"><c>file:mode()</c></seealso><c>]</c></tag> + <item> + <p>This specifies the file modes to use when opening the log + file, + see <seealso marker="file#open-2"><c>file:open/2</c></seealso>. + If <c>modes</c> are not specified, the default list used + is <c>[raw,append,delayed_write]</c>. If <c>modes</c> are + specified, the list replaces the default modes list with the + following adjustments:</p> + <list> + <item> + If <c>raw</c> is not found in the list, it is added. + </item> + <item> + If none of <c>write</c>, <c>append</c> or <c>exclusive</c> is + found in the list, <c>append</c> is added.</item> + <item>If none of <c>delayed_write</c> + or <c>{delayed_write,Size,Delay}</c> is found in the + list, <c>delayed_write</c> is added.</item> + </list> + <p>Log files are always UTF-8 encoded. The encoding cannot be + changed by setting the mode <c>{encoding,Encoding}</c>.</p> + <p>The value is set when the handler is added, and it cannot + be changed in runtime.</p> + <p>Defaults to <c>[raw,append,delayed_write]</c>.</p> + </item> + <tag><marker id="max_no_bytes"/><c>max_no_bytes = pos_integer() | infinity</c></tag> + <item> + <p>This parameter specifies if the log file should be rotated + or not. The value <c>infinity</c> means the log file will + grow indefinitely, while an integer value specifies at which + file size (bytes) the file is rotated.</p> + <p>Defaults to <c>infinity</c>.</p> + </item> + <tag><marker id="max_no_files"/><c>max_no_files = non_neg_integer()</c></tag> + <item> + <p>This parameter specifies the number of rotated log file + archives to keep. This has meaning only + if <seealso marker="#max_no_bytes"><c>max_no_bytes</c></seealso> + is set to an integer value.</p> + <p>The log archives are + named <c>FileName.0</c>, <c>FileName.1</c>, + ... <c>FileName.N</c>, where <c>FileName</c> is the name of + the current log file. <c>FileName.0</c> is the newest of the + archives. The maximum value for <c>N</c> is the value + of <c>max_no_files</c> minus 1.</p> + <p>Notice that setting this value to <c>0</c> does not turn of + rotation. It only specifies that no archives are kept.</p> + <p>Defaults to <c>0</c>.</p> + </item> + <tag><marker id="compress_on_rotate"/><c>compress_on_rotate = boolean()</c></tag> + <item> + <p>This parameter specifies if the rotated log file archives + shall be compressed or not. If set to <c>true</c>, all + archives are compressed with <c>gzip</c>, and renamed + to <c>FileName.N.gz</c></p> + <p><c>compress_on_rotate</c> has no meaning if <seealso + marker="#max_no_bytes"><c>max_no_bytes</c></seealso> has the + value <c>infinity</c>.</p> + <p>Defaults to <c>false</c>.</p> + </item> + <tag><marker id="file_check"/><c>file_check = non_neg_integer()</c></tag> + <item> + <p>When <c>logger_std_h</c> logs to a file, it reads the file + information of the log file prior to each write + operation. This is to make sure the file still exists and + has the same inode as when it was opened. This implies some + performance loss, but ensures that no log events are lost in + the case when the file has been removed or renamed by an + external actor.</p> + <p>In order to allow minimizing the performance loss, the + <c>file_check</c> parameter can be set to a positive integer + value, <c>N</c>. The handler will then skip reading the file + information prior to writing, as long as no more + than <c>N</c> milliseconds have passed since it was last + read.</p> + <p>Notice that the risk of loosing log events grows when + the <c>file_check</c> value grows.</p> + <p>Defaults to 0.</p> + </item> + <tag><c>filesync_repeat_interval = pos_integer() | no_repeat</c></tag> <item> <p>This value, in milliseconds, specifies how often the handler does a file sync operation to write buffered data to disk. The handler attempts @@ -97,12 +172,13 @@ standard handler and the disk_log handler, and are documented in the <seealso marker="logger_chapter#overload_protection"><c>User's Guide</c> </seealso>.</p> - <p>Notice that if changing the configuration of the handler in runtime, - the <c>type</c> parameter must not be modified.</p> + <p>Notice that if changing the configuration of the handler in + runtime, the <c>type</c>, <c>file</c>, or <c>modes</c> parameters + must not be modified.</p> <p>Example of adding a standard handler:</p> <code type="none"> logger:add_handler(my_standard_h, logger_std_h, - #{config => #{type => {file,"./system_info.log"}, + #{config => #{file => "./system_info.log", filesync_repeat_interval => 1000}}). </code> <p>To set the default handler, that starts initially with @@ -110,7 +186,7 @@ logger:add_handler(my_standard_h, logger_std_h, change the Kernel default logger configuration. Example:</p> <code type="none"> erl -kernel logger '[{handler,default,logger_std_h, - #{config => #{type => {file,"./log.log"}}}}]' + #{config => #{file => "./log.log"}}}]' </code> <p>An example of how to replace the standard handler with a disk_log handler at startup is found in the @@ -121,7 +197,7 @@ erl -kernel logger '[{handler,default,logger_std_h, <funcs> <func> - <name name="filesync" arity="1" clause_i="1"/> + <name name="filesync" arity="1" clause_i="1" since="OTP 21.0"/> <fsummary>Writes buffered data to disk.</fsummary> <desc> <p>Write buffered data to disk.</p> |