improg: Program integration input module
Module Name: | improg |
Authors: | Jean-Philippe Hilaire <jean-philippe.hilaire@pmu.fr> & Philippe Duveau <philippe.duveau@free.fr> |
Purpose
This module allows rsyslog to spawn external command(s) and consume message from pipe(s) (stdout of the external process).
Limitation: select() seems not to support usage of printf(…) or fprintf(stdout,…). Only write(STDOUT_FILENO,…) seems to be efficient.
The input module consume pipes form all external programs in a mono-threaded runInput method. This means that data treatments will be serialized.
Optionally, the module manage the external program through keyword sent to it using a second pipe to stdin of the external process.
An operational sample in C can be found @ “github.com/pduveau/jsonperfmon”
Also a bash’s script is provided as tests/improg-simul.sh. The echo and read (built-in) can be used to communicate with the module. External commands can not be used to communicate. printf is unable to send data directly to the module but can used through a variable and echo.
Compile
To successfully compile improg module.
./configure –enable-improg …
Configuration Parameters
Action Parameters
Binary
type | mandatory | format | default |
|---|---|---|---|
string | yes | command arguments… |
Command line : external program and arguments
Tag
type | mandatory | format | default |
|---|---|---|---|
string | yes | none |
The tag to be assigned to messages read from this file. If you would like to
see the colon after the tag, you need to include it when you assign a tag
value, like so: tag="myTagValue:".
Facility
type | mandatory | format | default |
|---|---|---|---|
string | no | facility|number | local0 |
The syslog facility to be assigned to messages read from this file. Can be
specified in textual form (e.g. local0, local1, …) or as numbers (e.g.
16 for local0). Textual form is suggested.
Severity
type | mandatory | format | default |
|---|---|---|---|
string | no | severity|number | notice |
The syslog severity to be assigned to lines read. Can be specified
in textual form (e.g. info, warning, …) or as numbers (e.g. 6
for info). Textual form is suggested.
confirmMessages
type | mandatory | format | default |
|---|---|---|---|
binary | no | on|off | on |
Specifies whether the external program needs feedback from rsyslog via stdin.
When this switch is set to “on”, rsyslog confirms each received message.
This feature facilitates error handling: instead of having to implement a retry
logic, the external program can rely on the rsyslog queueing capabilities.
The program receives a line with the word ACK from its standard input.
Also, the program receives a STOP when rsyslog ask the module to stop.
signalOnClose
type | mandatory | format | default |
|---|---|---|---|
binary | no | on|off | off |
Specifies whether a TERM signal must be sent to the external program before closing it (when either the worker thread has been unscheduled, a restart of the program is being forced, or rsyslog is about to shutdown).
closeTimeout
type | mandatory | format | default |
|---|---|---|---|
number | no | 200 |
Specifies whether a KILL signal must be sent to the external program in case it does not terminate within the timeout indicated by closeTimeout (when either the worker thread has been unscheduled, a restart of the program is being forced, or rsyslog is about to shutdown).
killUnresponsive
type | mandatory | format | default |
|---|---|---|---|
binary | no | on|off | on |
Specifies whether a KILL signal must be sent to the external program in case it does not terminate within the timeout indicated by closeTimeout (when either the worker thread has been unscheduled, a restart of the program is being forced, or rsyslog is about to shutdown).
Stop sequence
If confirmMessages is set to on, a STOP is written in stdin of the child.
If signalOnClose is set to “on”, a TERM signal is sent to the child.
The pipes with the child process are closed (the child will receive EOF on stdin),
Then, rsyslog waits for the child process to terminate during closeTimeout,
If the child has not terminated within the timeout, a KILL signal is sent to it.
See also
Help with configuring/using Rsyslog:
Mailing list - best route for general questions
GitHub: rsyslog source project - detailed questions, reporting issues that are believed to be bugs with
Rsyslog
See also
Contributing to Rsyslog:
Source project: rsyslog project README.
Documentation: rsyslog-doc project README
Copyright 2008-2023 Rainer Gerhards (Großrinderfeld), and Others.