Implement PID File for go-dnscollector to Enable SIGHUP Configuration Reload

[4quarks]

Implement PID File for go-dnscollector to Enable SIGHUP Configuration Reload

Description:
Now that SIGHUP is implemented on the go-dnscollector side (see), we (pDNSSOC) need to integrate this functionality for configuration reload without restarting the process. This will allow us to make changes on-the-fly, such as reading updated files, by sending a SIGHUP signal to the process without having to restart the process manually.

Background:
It became common practice for daemonized processes to use SIGHUP for configuration reload. This allows changes to be made without terminating the process.

Current Implementation Steps:

1. Find the process number of go-dnscollector.
2. Run the following command to reload the configuration:

   kill -SIGHUP 21371  # Assuming 21371 is the PID of the running go-dnscollector

Challenge:
The PID changes every time the process restarts, which makes it difficult to automate this with a static command.

Proposed Solution:
Implement a PID file in go-dnscollector that stores the current PID of the running process. This PID file will be created on startup and can be referenced to send the SIGHUP signal.

Benefits:

• Simplifies the process of sending SIGHUP signals.
• Eliminates the need to restart the process for configuration changes.
• Potentially allows us to remove the dependency on supervisord, as it is currently used only for restarting on config changes.
• Follows a good and common industry practice.

Additional Notes:

• Confirm if Denis has implemented the PID file functionality. If not, this issue should prioritize that implementation.
• If we (pDNSSOC) can ditch supervisord, a Python script inside fetch-iocs can monitor file changes and send the SIGHUP signal accordingly.

References:

• Run Program and Generate PID

Action Items:

• Implement PID file creation in go-dnscollector.
• We (pDNSSOC) will have to create a script to read the PID from the PID file and send the SIGHUP signal.

[dmachard]

My proposal

Add global settings to enable PID file creation.

global:
  pid-file: "/path/to/your/pidfile.pid"

By default, this setting will be empty. If the pid-file parameter is configured, the program will create a PID file.

[4quarks]

This sounds perfect for us. Thanks!

[dmachard]

feature implemented in master branch

[4quarks]

The issue seems to be resolved. Thanks for your quick action!