go-systemd

Go bindings to systemd. The project has several packages:

activation - for writing and using socket activation from Go
daemon - for notifying systemd of service status changes
dbus - for starting/stopping/inspecting running services and units
journal - for writing to systemd's logging service, journald
sdjournal - for reading from journald by wrapping its C API
login1 - for integration with the systemd logind API
machine1 - for registering machines/containers with systemd
unit - for (de)serialization and comparison of unit files

Socket Activation

An example HTTP server using socket activation can be quickly set up by following this README on a Linux machine running systemd:

https://github.com/coreos/go-systemd/tree/main/examples/activation/httpserver

systemd Service Notification

The daemon package is an implementation of the sd_notify protocol. It can be used to inform systemd of service start-up completion, watchdog events, and other status changes.

D-Bus

The dbus package connects to the systemd D-Bus API and lets you start, stop and introspect systemd units. API documentation is available online.

Debugging

Create /etc/dbus-1/system-local.conf that looks like this:

<!DOCTYPE busconfig PUBLIC
"-//freedesktop//DTD D-Bus Bus Configuration 1.0//EN"
"http://www.freedesktop.org/standards/dbus/1.0/busconfig.dtd">
<busconfig>
    <policy user="root">
        <allow eavesdrop="true"/>
        <allow eavesdrop="true" send_destination="*"/>
    </policy>
</busconfig>

Journal

Writing to the Journal

Using the pure-Go journal package you can submit journal entries directly to systemd's journal, taking advantage of features like indexed key/value pairs for each log entry.

Reading from the Journal

The sdjournal package provides read access to the journal by wrapping around journald's native C API; consequently it requires cgo and the journal headers to be available.