jasraj/kdb-systemd

kdb integration with systemd notification mechanism

systemd Notification Interface for kdb

This repository provides a kdb library to integrate with systemd. It provides the following features:

• Support for Type=Notify systemd services, providing READY and STOPPING signals
• Support for WatchdogSec= systemd watchdog monitoring
  • NOTE: This requires the kdb+ process to be the main process started by systemd. Use exec instead of backgrounding a process

An example systemd service file is provided in the repository.

NOTE: This library requires the shared object libkdbsystemd.so provided by the kdb-systemd-lib repository. Please ensure that this object is available in your target environment and it's location referenced in LD_LIBRARY_PATH.

This library has been written for use with the kdb-common set of libraries.

Building libkdbsystemd.so

See kdb-systemd-lib for build instructions

Using the Notification Library

When the library is loaded and .sdi.init is executed (see kdb-common require.q for more details), the following initialisation is performed:

1. Attempt to discover the find the required shared object (libkdbsystemd.so) within LD_LIBRARY_PATH
2. The systemd interface functions are loaded from the shared object into the .sdi.so namespace

.sdi.onProcessReady[]

This function should be called after the process initialistion phases is complete and you want to report back to systemd that the process is ready for use. This function also:

1. Configures the systemd watchdog (i.e. heartbeat) if configured in the systemd file (using the kdb-common cron.q library)
2. Configures notifying systemd when the process is about to exit (using the kdb-common event.q library)

.sdi.sendStatus[status]

This function allows you to send custom status strings to systemd for more detailed reporting.

Example:

q) .sdi.sendStatus "Status from kdb+"

> systemctl status kdb-service
   Active: active (running) since Fri 2019-07-05 13:48:33 BST; 29s ago
 Main PID: 8801 (q)
   Status: "Status from kdb+"