Erlang -- sasl

# sasl

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Application

sasl

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Application Summary

The SASL application

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Description

The SASL application provides the following services:

- alarm_handler
- release_handler
- systools

Note

The SASL application in OTP has nothing to do with "Simple Authentication and Security Layer" (RFC 4422).

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Configuration

The following configuration parameters are defined for the SASL application. For more information about configuration parameters, see app(4) in Kernel.

All configuration parameters are optional.

start_prg = string()

  Specifies the program to be used when restarting the system during release installation. Default is $OTP_ROOT/bin/start.

masters = [atom()]

  Specifies the nodes used by this node to read/write release information. This parameter is ignored if parameter client_directory is not set.

client_directory = string()

  This parameter specifies the client directory at the master nodes. For details, see Release Handling in OTP Design Principles. This parameter is ignored if parameter masters is not set.

static_emulator = true | false

  Indicates if the Erlang emulator is statically installed. A node with a static emulator cannot switch dynamically to a new emulator, as the executable files are written into memory statically. This parameter is ignored if parameters masters and client_directory are not set.

releases_dir = string()

  Indicates where the releases directory is located. The release handler writes all its files to this directory. If this parameter is not set, the OS environment parameter RELDIR is used. By default, this is $OTP_ROOT/releases.

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Deprecated Error Logger Event Handlers and Configuration

In Erlang/OTP 21.0, a new API for logging was added. The old error_logger event manager, and event handlers running on this manager, still work, but they are not used by default.

The error logger event handlers sasl_report_tty_h and sasl_report_file_h, were earlier used for printing the so called SASL reports, i.e. supervisor reports, crash reports, and progress reports. These reports are now also printed by the default logger handler started by the Kernel application. Progress reports are by default stopped by the primary log level, but can be enabled by setting this level to info, for example by using the Kernel configuration parameter logger_level.

If the old error logger event handlers are still desired, they must be added by calling error_logger:add_report_handler/1,2.

sasl_report_tty_h

  Formats and writes supervisor reports, crash reports, and progress reports to stdio. This error logger event handler uses error_logger_format_depth in the Kernel application to limit how much detail is printed in crash and supervisor reports.

sasl_report_file_h

  Formats and writes supervisor reports, crash report, and progress report to a single file. This error logger event handler uses error_logger_format_depth in the Kernel application to limit the details printed in crash and supervisor reports.

A similar behaviour, but still using the new logger API, can be obtained by setting the Kernel application environment variable logger_sasl_compatible to true. This adds a second instance of the standard Logger handler, named sasl, which only prints the SASL reports. No SASL reports are then printed by the Kernel logger handler.

The sasl handler is configured according to the values of the following SASL application environment variables.

sasl_error_logger = Value

  Value is one of the following:

  tty

    Installs sasl_report_tty_h in the error logger. This is the default option.

  {file,FileName}

    Installs sasl_report_file_h in the error logger. All reports go to file FileName, which is a string. The file is opened in write mode with encoding utf8.

  {file,FileName,Modes}

    Same as {file,FileName}, except that Modes allows you to specify the modes used for opening the FileName given to the file:open/2 call. By default, the file is opened in write mode with encoding utf8. Use [append] to have the FileName open in append mode. A different encoding can also be specified. FileName is a string.

  false

    No SASL error logger handler is installed.

errlog_type = error | progress | all

  Restricts the error logging performed by the specified sasl_error_logger to error reports or progress reports, or both. Default is all.

utc_log = true | false

  If set to true, all dates in textual log outputs are displayed in Universal Coordinated Time with the string UTC appended.

The error logger event handler log_mf_h can also still be used. This event handler writes all events sent to the error logger to disk. Multiple files and log rotation are used. For efficiency reasons, each event is written as a binary. For more information about this handler, see the STDLIB Reference Manual.

To activate this event handler, three SASL configuration parameters must be set:

error_logger_mf_dir = string() | false

  Specifies in which directory log_mf_h is to store its files. If this parameter is undefined or false, the log_mf_h handler is not installed.

error_logger_mf_maxbytes = integer()

  Specifies the maximum size of each individual file written by log_mf_h. If this parameter is undefined, the log_mf_h handler is not installed.

error_logger_mf_maxfiles = 0<integer()<256

  Specifies the number of files used by log_mf_h. If this parameter is undefined, the log_mf_h handler is not installed.

The new logger_disk_log_h might be an alternative to log_mf_h if log rotation is desired. This does, however, write the log events in clear text and not as binaries.

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See Also

alarm_handler(3), error_logger(3), logger(3), log_mf_h(3), rb(3), release_handler(3), systools(3)