Process Status Module

Introduction

This module is an ASYN port driver that can provide process information. The EPICS IOC and the processorp processes of interest must run on the same Linux host.

The documentation still under development. Look at the test app for example on usage.

Identifying process to monitor

There are two commands that must be run in IOC's st.cmd, or equivilent, file.

ProcessStatus_Initialise

This command both initialises the driver, and sets the weeor warnong level. The command takes a single integer parameter. The expected values are:

• 0 report errors only
• 1 report errors and warnings
• 2 report errors, warnings and info

Example:

ProcessStatus_Initialise (2)

ProcessStatus_Configure

This command identifies the process to monitor. The command takes four parameters. These are:

• 1: The asyn port name.
• 2: The program name (out of /proc/<pid>/cmdline). Examples: /bin/bash, kwrite. Note: how the process was launched impacts wheather full path name or just the basename appears in /proc/<pid>/cmdline. This parameter must match exactly.
• 3: When you want to distiguish between different instances of the same executable, this nominates the parameter number (or 0 if not applicable) to be used to identify each instance,
• 4: When #3 is specified, this provides a regular expression used to match the parameter.

Examples:

ProcessStatus_Configure ("PSBASH",  "/bin/bash",                 0, "")
ProcessStatus_Configure ("PSINIT",  "/usr/lib/systemd/systemd",  0, "")
ProcessStatus_Configure ("PSSLEEP", "sleep",                     1, "^500$")
ProcessStatus_Configure ("PSKRITE", "kwrite",                    1, "st.cmd")

Loading the template (example)

dbLoadRecords ("db/process_status.template", "PORT=PSBASH,  PROCESS=BASH,   DESC=any bash")
dbLoadRecords ("db/process_status.template", "PORT=PSINIT,  PROCESS=INIT,   DESC=systemd")
dbLoadRecords ("db/process_status.template", "PORT=PSSLEEP, PROCESS=SLEEP,  DESC=sleep 500")
dbLoadRecords ("db/process_status.template", "PORT=PSKRITE, PROCESS=KWRITE, DESC=kwrite st.cmd")

A substituion file may be more appropriate if many processes are being monitored.

EPICS Database template

The module includes process_status.template which can be used as is, or as a guide or inspiration to creating your template file.

The template provides three records. These are described below.

$(PROCESS):STATUS

This is an mbbi record. The status are:

State	Severity	Comment
Unknown	INVALID	Undefined
Stopped	MAJOR	No processes match the specified criteria
Running	NO_ALARM	One process matches the criteria
Multiple	MINOR	Tow or more processes matches the criteria

$(PROCESS):COUNT

This is a longin record. In provides a count of the number of processes that match the specified criteria.

$(PROCESS):PID

This is a longin record. If a single process matches the specified criteria, i.e. the status is running, this record provides the process id. If no processes or multiple processes match, the record is set to 0.

Last updated: Sat May 13 18:10:14 2023