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Formula Processor

Formula Processor is a microservice that is responsible for calculation of alert conditions, represented as JavaScript formulas. Formula Processor listens to changes of statistic values on which alert formulas depend and recompute alert formulas when the change is detected. Alert formula values are then distributed to other microservices.

FormulaProcessor is installed with Genesys Pulse Collector. Files are located inside the <Genesys Pulse Collector installation folder>/microservices/FormulaProcessor directory.

You need to have Formula Processor configured and running in order to enable alert condition calculations.

Formula Processor depends on the following Genesys Pulse microservices:

Configuration

The Formula Processor microservice does not use Genesys Configuration Server. All the configuration is defined in the configuration file(s). All changes in the configuration file take effect after the microservice restart.

Tip
Starting with 9.0.008.03, Formula Processor requires configuration files in YAML format. You can convert existing configuration from INI to YAML format using the microservices/FormulaProcessor/contrib/cfg2yaml.py script.

All options of the configuration file are divided into sections and subsections. Empty sections are ignored.

For versions < 9.0.008.03 (INI format) 

[Section_1]
Option_1 = Value_1

[Section_1.Subsection]
Option_11 = Value_11

[Section_2]
Option_2 = Value_2

[Section_3]
List_Option_3 = Value_31,Value_32

For versions >= 9.0.008.03 (YAML format) 

Section_1:
     Option_1: Value_1
     Subsection:
          Option_11: Value_11

Section_2:
     Option_2: Value_2

Section_3:
     List_Option_3:
         - Value_31
         - Value_32

Below are all the options supported by the Formula Processor microservice. All options are grouped by sections.

log

The section is used to configure microservice's log subsystem. The following options in the section are supported:

  • channel
    Name of the default log channel.
    Default value: Name of the executable
    Valid values: String
  • verbose
    Log verbose level.
    Default value: interaction
    Valid values: 
    • all – all messages (same as debug)
    • debug – debug/trace/normal/info/warning/error messages
    • trace – trace/normal/info/warning/error messages
    • interaction – normal/info/warning/error messages
    • alarm – warning/error messages
  • all
    List of log destinations to log all messages.
    Default value: Empty list
    Valid values: 
    • stdout – standard console output
    • syslog – system log
    • <path> – path to the log file
  • debug
    List of log destinations to log debug messages.
    Default value: Empty list
    Valid values: stdout, syslog, <path>
  • trace
    List of log destinations to log trace messages.
    Default value: Empty list
    Valid values: stdout, syslog, <path>
  • interaction
    List of log destinations to log normal messages.
    Default value: Empty list
    Valid values: stdout, syslog, <path>
  • standard
    List of log destinations to log info messages.
    Default value: Empty list
    Valid values: stdout, syslog, <path>
  • alarm
    List of log destinations to log warning/error messages.
    Default value: Empty list
    Valid values: stdout, syslog, <path>
  • segment
    Split log files in segments of the specified size.
    Default value: false
    Valid values: 
    • no, false – do not split log files
    • <size>[kb|mb] – segment size
      • kb – kilobytes (default)
      • mb – megabytes
  • expire
    Keep the specified number of log file segments. If the value of 0 is specified, then segments are not expired.
    Default value: 0
    Valid values: Positive integers, 0

FormulaProcessor

This section provides some general settings. The following options in the section are supported:

  • add_message_timestamp
    Add additional timestamp to formula result messages.
    Default value: false
    Valid values: true, false
  • announce_period
    Number of seconds between sending heartbeat messages.
    Default value: 10
    Valid values: Positive integers

Engine

This subsection of FormulaProcessor provides settings for the formula computation engine. The following options in the section are supported:

  • script_execution_threads
    Number of script execution threads.
    Default value: 10
    Valid values: Integers from 1 to 256
  • script_execution_queue_size
    Maximum size of the queue of requests for every script execution thread. If the value of 0 is specified then the queue is not limited.
    Default value: 0
    Valid values: Positive integers, 0
  • gc_period
    Number of seconds between garbage collections.
    Default value: 1800
    Valid values: Integers from 1 to 86400
  • min_object_inactivity
    Number of seconds of object's inactivity (an absence of any new data for the object) sufficient to mark it as garbage.
    Default value: 900
    Valid values: Integers from 1 to 86400
  • script_parsing_timeout
    Script parsing timeout (in ms).
    Default value: 2000
    Valid values: Integers from 1 to 60000
  • script_execution_timeout
    Formula evaluation timeout (in ms).
    Default value: 1000
    Valid values: Integers from 1 to 60000
  • idle_notification_period
    Scripting engine idle notification period (in ms).
    Default value: 1000
    Valid values: Integers from 1 to 60000
  • recomputation_period
  • Formula re-computation period (in secs).
    Default value: 60
    Valid values: Integers from 1 to 3600

MeasureSubscriber

The section describes how the Formula Processor microservice interacts with the MeasureWatcher microservice. The following options in the section are supported:

  • target
    The URI of the endpoint to connect to.
    Default value: No default value
    Valid values: 
    • [dns:///]<host>:<port> – a hostname/port combination
    • unix:<path> – the UNIX scheme is used to create and connect to UNIX domain sockets. The path represents the absolute or relative path to the desired socket
    • ipv4:<host>:<port> – a pre-resolved ipv4 dotted decimal address/port combination
    • ipv6:[<host>]:<port> – a pre-resolved ipv6 address/port combination
  • reconnect_delay
    Delay (in secs) before attempting to reconnect to the MeasureWatcher service.
    Default value: 10
    Valid values: Positive integers, 0
  • measure_types
    A list of measure types which should be queried. If no types are specified, query all measures.
    Default value: Empty list
    Valid values: GENERIC, FORMULA

AeronPublisher

The section describes how the microservice should publish the collected statistic values via Aeron. The following options in the section are supported:

  • driver_directory
    Directory of the Aeron media driver. It should be the same as the media driver uses. On Linux systems it is better to be a directory inside the /dev/shm/ directory.
    Default value: System specific
    Valid values: String
  • driver_timeout
    The amount of time, in milliseconds, that the publisher waits until it determines the the Aeron media driver is unavailable.
    Default value: 2000
    Valid values: Positive integers
  • channel.control
    Multi-Destination-Cast (MDC) control address to be used for dynamically allocating new destination streams.
    Default value: No default value
    Valid values: String in the <host>:<port> format
  • channel.uri
    URI of the Aeron channel. If specified, all other channel parameters are ignored. If the control option is not specified then the parameter is required.
    Default value: No default value
    Valid values: String
  • reconnect_delay
    Delay (in secs) before attempting to reconnect to the media driver.
    Default value: 10
    Valid values: Positive integers, 0

AeronSubscriber

The section provides detailed Aeron channel options. The following options in the section are supported:

  • driver_directory
    Aeron driver directory. Should be the same as the one that the media driver is using.
    Default value: System specific
    Valid values: String
  • driver_timeout
    The amount of time, in milliseconds, that the subscriber waits until it determines the the Aeron media driver is unavailable.
    Default value: 2000
    Valid values: Positive integers
  • reconnect_delay
    Delay (in secs) before attempting to reconnect to the media driver.
    Default value: 10
    Valid values: Positive integers, 0

channel

This subsection of AeronSubscriber describes how the Formula Processor microservice should receive statistical values from the StatServer Data Provider microservice via Aeron. The following options in the section are supported:

  • control
    Multi-Destination-Cast (MDC) control address that is used for dynamically allocating new destination streams.
    Default value: No default value
    Valid values: String in the <host>:<port> format
  • endpoint
    Local endpoint address that is used for listening incoming messages.
    Default value: No default value
    Valid values: String in the <host>:<port> format
  • uri
    Aeron channel URI. If specified, all other options in this section are ignored. If neither control nor endpoint are specified then this option is required. Multiple channel specifications are acceptable. In case of a single channel, the channel name can be omitted.
    Default value: No default value
    Valid values: String

How to Run FormulaProcessor

The FormulaProcessor is implemented as a standalone executable. The following command line options are supported:

  • -h, --help
    Print help screen and exit.
  • -c, --config-file FILE
    Specifies the path to the file that contains the configuration for the microservice. The option can be specified multiple times. In this case, all the configurations are merged. If no configuration files are specified, the FormulaProcessor.cfg file located in the executable's directory is used.
  • -D, --define NAME=VALUE
    Defines the value of the configuration property. The option can be specified multiple times. The property values specified in command line take precedence over the values specified in the configuration files.
  • --service NAME
    The microservice is running as a system service.
    On Windows, the option is added automatically during the creation of the service and should not be used directly by the user.
    On Linux, if the option is specified in the command line, then the microservice is running in the background.
    This option is modified in the 9.0.001 release. The short option -s is no longer supported.
  • --install[=INSTANCE_NAME]
    Creates a Windows service for the microservice. If an instance name is not specified, then the name of the service is FormulaProcessor. If the instance name is provided, then the name of the service is FormulaProcessor#INSTANCE_NAME.
    If additional command line options are specified, they are used to run the service.
    This option is introduced in the 9.0.001 release.
  • --remove[=INSTANCE_NAME]
    Removes a Windows service for the microservice. If an instance name is not specified, then the name of the service is FormulaProcessor. If the instance name is provided, then the name of the service is FormulaProcessor#INSTANCE_NAME.
    This option is introduced in the 9.0.001 release.

Run as a Service on Windows

To create a Windows service, perform the following command:
path\to\installation\FormulaProcessor.exe -c path\to\config\file --install

You can use the NET command in a Windows command prompt to manage the service:

  • NET START FormulaProcessor
  • NET STOP FormulaProcessor

To remove the service, perform the following command:
path\to\installation\FormulaProcessor.exe --remove

If multiple instances of the microservice are required to run on the same host, you can create an additional instance of the service:
path\to\installation\FormulaProcessor.exe -c path\to\config\file --install=<instance_name>

You can use the NET command in a Windows command prompt to manage the service:

  • NET START FormulaProcessor#<instance_name>
  • NET STOP FormulaProcessor#<instance_name>

To remove the service, perform the following command:
path\to\installation\FormulaProcessor.exe --remove=<instance_name>

Run as a Service on Linux

Create a separate systemd service configuration file for each instance of the Formula Processor service you need to run.
For example, create the systemd service configuration file /etc/systemd/system/pulse-formula-processor.service with the following content: 

[Unit]
Description=Pulse Formula Processor

[Service]
ExecStart=/path/to/installation/FormulaProcessor -c /path/to/config/file --service
Type=forking

[Install]
WantedBy=multi-user.target

If multiple instances of the microservice running on the same host are required, you can create an additional instance of the service /etc/systemd/system/pulse-formula-processor-instance_name.service: 

[Unit]
Description=Pulse Formula Processor <instance_name>

[Service]
ExecStart=/path/to/installation/FormulaProcessor -c /path/to/config/file --service=<instance_name>
Type=forking

[Install]
WantedBy=multi-user.target

You can use systemctl(1) to manage these services. Type man systemctl for more information.

Important
Make sure that Aeron Media Driver is configured and running on the host.
This page was last edited on November 17, 2023, at 14:45.
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