[mythtv-commits] Ticket #12148: Feature patch to support systemd ready notification in backend

[MythTV]

#12148: Feature patch to support systemd ready notification in backend
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     Reporter:  Gary Buhrmaster                  |      Owner:
  <gary.buhrmaster@…>                            |     Status:  new
         Type:  Patch - Feature                  |  Milestone:  unknown
     Priority:  minor                            |    Version:  Master Head
    Component:  MythTV - General                 |   Keywords:
     Severity:  medium                           |
Ticket locked:  0                                |
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 Feature patch to support systemd ready notification in backend

 This is a feature patch to support the ability to use systemd After
 functionality for units that wish to wait until the backend has completed
 initialization.

 Systemd is the system management daemon for many newer Linux distros.  One
 of its features is the ability to have startup dependencies based on the
 the After option in a unit section.
 This feature patch adds in a call to the sd_notify function specifying
 that the backend process is READY after startup has completed.  This will
 allow other systemd units to wait for the backend to complete
 initialization using the After (and a Requires if appropriate) unit
 options, or to test for the backend being ready via systemctl status
 (perhaps useful in a combined BE/FE situation where the FE wishes to wait
 for the BE to complete initialization).

 Note that the sd_notify call is defined to be a no-op if the current
 system was not booted using systemd, making it (theoretically) safe to
 invoke sd_notify on platforms transitioning to systemd from alternative
 init systems.

 The configure script is modified to autodetect (using pkg-config) the
 required functionality and libraries and default to enabling systemd ready
 notification if the build dependencies are met.  A new configure option:
 --disable-systemd_notify is available to insure that support is not
 compiled into mythbackend if required.

 (Lightly) tested in a development environment.

 Release note item: Users/Packagers using systemd may want to consider
 adding the new build requirements (systemd-devel) to enable support, and
 to change the Type from simple to notify in their service files.


 github ref:
 https://github.com/garybuhrmaster/mythtv/commit/70293a6b766b3c761ba023d6f816e79c5d10de3d

 github git-am ref:
 https://github.com/garybuhrmaster/mythtv/commit/70293a6b766b3c761ba023d6f816e79c5d10de3d.patch

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Ticket URL: <https://code.mythtv.org/trac/ticket/12148>
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