Table of contents

Description

The Log Monitor & Dispatcher, known as LOGMOND, is a special program which monitors a guest LOG file produced by Charon and executes a customized script when it detects removal of a license.

It runs in the background (as a program or as a service) and periodically scans a specified LOG file. When it detects a message with the code 00000424 ("Detected removal of a license") or 0000002A or 00000351 for backward compatibility, it submits the nolicense.bat procedure (this BAT file must be created manually). It also invokes the license_changed.bat script, if it exists, when it detects a message with code 0000040B / "License has changed. License detected and online".

The Log Monitor & Dispatcher service is installed as EmulatorLogMonitor. By default it is installed in such a way that requires explicit actions to be started (either through a command line interface or using the standard ways of service management). For unattended execution, change the service’s configuration so that Windows starts the service automatically.

The tool requires a specific file "nolicense.bat", and optionally a file named "license_changed.bat", containing some specific instructions to be taken in situation of license absence or license change. These files must be created in the virtual machine's home directory.

Recommendations

• Create a specific folder to hold the Charon configuration and log files, the nolicense.bat file, the license_changed.bat if needed, and any specific action script you would add.
• Use the rotating log files mechanism or use a single log file with "append" mode.
• Install and start the Charon log monitor service, named "EmulatorLogMonitor": doing so you will not have to start logmond manually in interactive mode and newly added virtual machines services will be automatically taken into account. Use interactive mode for tests and debugging purpose.

Notes

• The log monitor utility will detect the absence or change of the dongle only at a specified interval, called the license check interval and defined by the license. Its default is set to 1 hour. In case you need to perform tests, you can send us a fresh C2V file and ask for an update to reduce this interval.
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• Once started the logmond utility will lock the virtual machine log file, you will not be able to move it, copy it or delete it. You will however be able to open it using the notepad utility or other log editors like baretail for example which will allow you to have a continuous view of the log with highlights (see: Charon Log files - Using baretail on Windows for syntax highlighting) or vim (see: Charon Log files - Using vim for syntax highlighting on Linux and Windows)..

Service setup example

Example below is based on a Charon-AXP V4.9 B19402 running on a Windows 2012 R2 server and emulating an AlphaServer DS20. All files (configuration, bin, rom and nolicense.bat) are located in C:\Charon, rotating log files are located in C:\Charon\logs

The configuration file is defined as follows:

Setup and start your virtual machine.

• Start the "Charon Virtual Machines Manager"
• Create your virtual machine and start it
  
  See Running and managing Charon-AXP for Windows or Running and managing Charon-VAX and Charon-PDP for Windows for details..

Install and start the log monitor service

• First, prepare a nolicense.bat file. See nolicense.bat considerations chapter further for more information if needed..

Example:

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Use the notepad for example to create the nolicense.bat script. We will here add a line in a log file:

echo %date% %time% dongle removed >>C:\Charon\logmond.log

The license_changed.bat script can also contain quite the same line:

echo %date% %time% license has changed >>C:\Charon\logmond.log

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• Install the log monitoring service and start it:
  
  These command lines must be executed as an administrator in order to manage the services 
  
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• Notes:
  
  • The "logmond -r" command removes the service if any
  • The "logmond -i" command installs the service
  • The "logmond -u" command starts the service
  • The powershell commands shows 2 logmond processes, one scans for new services, the other is monitoring the log file of the current service (myds20)
  • The EmulatorLogMonitor service running the logmond processes will discover already installed Charon virtual machines services. If a new virtual machine service is added, it's log file will be automatically discovered and monitored.
  • The logmond.exe file is located by default in the "C:\Program Files\Charon\Build_19402\x64" folder for Charon-AXP/VAX/PDP V4.9, "C:\Program Files\Charon\Build_20200\x64" for V4.10.

• In this test, two dongles were connected, the active one has been removed (1) producing the license changed message (2 and 3) then the last active dongle has been removed (4 and 5).
  During the tests the license check interval was set to 5 minutes therefore, when the dongle is disconnected, a message is sent telling there are only 4 minutes remaining before the DS20 stops
  .
  

Running the log monitor from the command line

The "logmond" utility has several parameters available. Use the "logmond -h" command to have a complete list.

Starting in background mode

In order to start the Log Monitor & Dispatcher as a background application:

1. Open "cmd.exe" from the "Start" menu.
2. Change current directory to the folder (presumably) containing the Charon configuration file.

3. Start the Log Monitor & Dispatcher using the following command line as an example:
   
   For single log file:

   ...> "C:\Program Files\Charon\Build_19402\x64\logmond" C:\my_Charon.log

   For rotating log file:

   ...> "C:\Program Files\Charon\Build_19402\x64\logmond" -l <log-directory> -p <log-prefix>

   where:

• • <log-directory> is the directory where the rotating log files are stored
  • <log-prefix> is the same as the "configuration_name" value in corresponding Charon configuration file (or "hw_model", if "configuration_name" is not specified).

Example:

To stop the Log Monitor & Dispatcher application, open the Task Manager, find the "logmond.exe" process and terminate it.

Debugging

To diagnose LOGMOND using trace feature:

1. Stop LOGMOND service using "--stop" (or "-d" or "--down"). This is not absolutely necessary though, as multiple running LOGMOND utilities do not affect each other.
   
   
2. Start "almost-as-a-service" LOGMOND with diagnostic trace using two command line switches: "-e" and "-t". This starts master task of LOGMOND which enumerates all Charon services and for each of them invokes slave task of LOGMOND. The master task of LOGMOND looks for installing or removal Charon services.
   1. When Charon service is installed, master creates new slave.
   2. When Charon service is removed, slave is terminated to. The slave task monitors LOG of particular Charon service.
   The "-t" switch enables trace windows, so you can see the process of monitoring.
   
   
3. To terminate "almost-as-a-service" LOGMOND master and all its slaves, bring focus to master's trace window, and press "Ctrl-C" ([X] button closes master task, but slaves continue to run unmastered).

The LOGMOND still supports backward compatibility mode, when it does NOT monitor ALL Charon services, but only monitors a particular folder or even a particular file. So, if you want to diagnose how it monitors a file, you can use the same "-t" option:

If you want to diagnose monitoring rotating log:

If you want to diagnose monitoring particular service:

When you install LOGMOND to run as a service it implicitly runs with "-e" option but without "-t". Alternatively you may install LOGMOND as a service with explicitly specified name of log file (for backward compatibility)

nolicense.bat considerations

LOGMOND always looks for nolicense.bat and license_changed.bat files in the current working directory. What is current working directory for LOGMOND depends on how it is invoked.

If you run LOGMOND with just path to log file, the LOGMOND inherits current working directory from command prompt it is invoked from. So, before you run LOGMOND this way, change prompt's working directory to where you keep your NOLICENSE.BAT file.

If you run LOGMOND with name of Charon service, the LOGMOND changes its current working directory to the Charon service's Home directory. So, keep the nolicense.bat and license_changed.bat files in the virtual machine's home directory.

If you run LOGMOND with "-e" option, each slave receives a particular name of Charon service, and therefore changes to the service's Home directory. So, keep the nolicense.bat and license_changed.bat files in the virtual machine's home directory.

Stromasys highly recommends to use logmond as a service, installing it with the "-i" option then starting it with "-u".

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