host.service_running fails on trusty for snapped service

[Drew Freiberger]

The latest charmhelpers.core.host.service_running() checks for systemd, then uses system() to call systemctl or service if init_is_systemd() is true. This init_is_systemd() is false on trusty.

It then falls back to checking for /etc/init/* or /etc/init.d/* files in upstart and sysv format startup.

This creates a gap related to snap-based systemd startup services, as snapd only installs startup scripts in /etc/systemd/system/snapd.XXXXX when installed on trusty.

charmhelpers should be updated to handle the special case of systemd-only services on trusty to support charms that use snapped services.

[Drew Freiberger (afreiberger)]

Suggest adding function systemd_is_installed() and add another elif systemd_is_installed(): return service('is-active', service_name) before line https://github.com/juju/charm-helpers/blob/master/charmhelpers/core/host.py#L308 that checks. This would cover a more generic case of using the os-native tools on trusty before reverting back to systemd, but would cover both snap and non-snap systemd-only services installed on trusty.

[Adam Dyess (addyess)]

Looking for Reviews:
  https://github.com/juju/charm-helpers/pull/494

[Adam Dyess (addyess)]

when charmhelpers 20.17 is available from pypi: re-run tests on prometheus-ceph-exporter and push charm to charm story

[Adam Dyess (addyess)]

https://pypi.org/project/charmhelpers/

[Adam Dyess (addyess)]

Available here:
https://jaas.ai/u/llama-charmers-next/prometheus-ceph-exporter/5