On Wed, Sep 27, 2023 at 06:19:07PM +0200, Andrea Bolognani wrote:
> We already use templating to generate sockets, which are all
> based off libvirtd's. Push the idea further, and extend it to
> cover services as well.
>
> This is more challenging, as the various modular daemons each have
> their own needs in terms of what system services needs to be
> available before they can be started, which other components of
> libvirt they depend on, and so on.
>
> In order to make this sort of per-service tweaks possible, we
> introduce a Python script that can merge two systemd units
> together. The script is aware of the semantics of systemd's unit
> definition format, so it can intelligently merge sections
> together.
>
> This generic systemd unit merging mechanism will also supersede
> the extremely ad-hoc @deps@ variable, which is currently used in
> a single scenario.
>
> Signed-off-by: Andrea Bolognani <abologna@xxxxxxxxxx>
> ---
> scripts/merge-systemd-units.py | 91 ++++++++++++++++++++++++++++++++++
> scripts/meson.build | 1 +
> src/meson.build | 22 ++++++++
> src/virtd-admin.socket.in | 13 +++++
> src/virtd-ro.socket.in | 13 +++++
> src/virtd-tcp.socket.in | 12 +++++
> src/virtd-tls.socket.in | 12 +++++
> src/virtd.service.in | 25 ++++++++++
> src/virtd.socket.in | 12 +++++
> 9 files changed, 201 insertions(+)
> create mode 100755 scripts/merge-systemd-units.py
> create mode 100644 src/virtd-admin.socket.in
> create mode 100644 src/virtd-ro.socket.in
> create mode 100644 src/virtd-tcp.socket.in
> create mode 100644 src/virtd-tls.socket.in
> create mode 100644 src/virtd.service.in
> create mode 100644 src/virtd.socket.in
>
> diff --git a/scripts/merge-systemd-units.py b/scripts/merge-systemd-units.py
> new file mode 100755
> index 0000000000..136bc8d416
> --- /dev/null
> +++ b/scripts/merge-systemd-units.py
> @@ -0,0 +1,91 @@
> +#!/usr/bin/env python3
Stick a license header of SPDX tag on this.
Also if you didn't already do it, run the file through 'black'
and let it do whatever it wants todo to formatting.
...reminds me we really ought to get around to running 'black'
on the rest of our existing python.
> +
> +import sys
> +
> +SECTIONS = [
> + '[Unit]',
> + '[Service]',
> + '[Socket]',
> + '[Install]',
> +]
> +
> +
> +def parse_unit(unit_path):
> + unit = {}
> + current_section = '[Invalid]'
> +
> + with open(unit_path) as f:
> + for line in f:
> + line = line.strip()
> +
> + if line == '':
> + continue
> +
> + if line[0] == '[' and line[-1] == ']':
> + if line not in SECTIONS:
> + print('Unknown section {}'.format(line))
> + sys.exit(1)
> +
> + current_section = line
> + continue
> +
> + if current_section not in unit:
> + unit[current_section] = []
> +
> + unit[current_section].append(line)
> +
> + if '[Invalid]' in unit:
> + print('Contents found outside of any section')
> + sys.exit(1)
> +
> + return unit
> +
> +
> +def format_unit(unit):
> + lines = []
> +
> + for section in SECTIONS:
> + if section not in unit:
> + continue
> +
> + lines.append(section)
> +
> + for line in unit[section]:
> + lines.append(line)
> +
> + lines.append('')
> +
> + return '\n'.join(lines)
> +
> +
> +def merge_units(base, extra):
> + merged = {}
> +
> + for section in SECTIONS:
> + if section in extra and section not in base:
> + print('Section {} in extra but not in base'.format(section))
> + sys.exit(1)
> +
> + if section not in base:
> + continue
> +
> + merged[section] = base[section]
> +
> + if section not in extra:
> + continue
> +
> + merged[section].extend(extra[section])
> +
> + return merged
> +
> +
> +if len(sys.argv) < 2:
> + print('usage: {} BASE EXTRA'.format(sys.argv[0]))
> + sys.exit(1)
> +
> +base = parse_unit(sys.argv[1])
> +extra = parse_unit(sys.argv[2])
> +
> +merged = merge_units(base, extra)
> +
> +sys.stdout.write(format_unit(merged))
> diff --git a/scripts/meson.build b/scripts/meson.build
> index 05b71184f1..65fd1e21c5 100644
> --- a/scripts/meson.build
> +++ b/scripts/meson.build
> @@ -19,6 +19,7 @@ scripts = [
> 'header-ifdef.py',
> 'hvsupport.py',
> 'hyperv_wmi_generator.py',
> + 'merge-systemd-units.py',
> 'meson-dist.py',
> 'meson-gen-authors.py',
> 'meson-gen-def.py',
> diff --git a/src/meson.build b/src/meson.build
> index 2fbf98b9fe..02c92621ba 100644
> --- a/src/meson.build
> +++ b/src/meson.build
> @@ -203,6 +203,8 @@ libvirtd_socket_admin_in = files('remote' / 'libvirtd-admin.socket.in')
> # * sockets - array of additional sockets (optional, default [ 'main', 'ro', 'admin' ])
> # * service_in - service source file (optional, default remote/libvirtd.service.in)
> # * socket_$name_in - additional socket source files (optional, default remote/libvirtd.socket.in )
> +# * service_extra_in - unit to merge with service_in (optional, default None)
> +# * socket_extra_in - unit to merge with socket_$name_in (optional, default None)
> # * deps - socket dependencies (optional, default '')
> virt_daemon_units = []
>
> @@ -817,6 +819,7 @@ if conf.has('WITH_LIBVIRTD')
> 'initconfdir': initconfdir,
> 'name': unit['name'],
> 'service': unit['service'],
> + 'SERVICE': unit['service'].to_upper(),
> 'sockprefix': unit.get('sockprefix', unit['service']),
> 'deps': unit.get('deps', ''),
> 'sockmode': sockmode,
> @@ -825,6 +828,15 @@ if conf.has('WITH_LIBVIRTD')
> service_in = unit.get('service_in', service_in_default)
> service_out = '@0@.service'.format(unit['service'])
>
> + if 'service_extra_in' in unit
> + service_in = configure_file(
> + input: [ service_in, unit['service_extra_in'] ],
> + output: '@0@.in'.format(service_out),
> + command: [ merge_systemd_units_prog, '@INPUT0@', '@INPUT1@' ],
> + capture: true,
> + )
> + endif
> +
> configure_file(
> input: service_in,
> output: service_out,
> @@ -843,6 +855,16 @@ if conf.has('WITH_LIBVIRTD')
> socket_in = unit.get('socket_@0@_in'.format(socket), socket_in_default)
> socket_out = '@0@-@1@.socket'.format(unit['service'], socket)
> endif
> +
> + if 'socket_extra_in' in unit
> + socket_in = configure_file(
> + input: [ socket_in, unit['socket_extra_in'] ],
> + output: '@0@.in'.format(socket_out),
> + command: [ merge_systemd_units_prog, '@INPUT0@', '@INPUT1@' ],
> + capture: true,
> + )
> + endif
> +
> configure_file(
> input: socket_in,
> output: socket_out,
> diff --git a/src/virtd-admin.socket.in b/src/virtd-admin.socket.in
> new file mode 100644
> index 0000000000..39bb0badea
> --- /dev/null
> +++ b/src/virtd-admin.socket.in
> @@ -0,0 +1,13 @@
> +[Unit]
> +Description=@name@ admin socket
> +Before=@service@.service
> +BindsTo=@service@.socket
> +After=@service@.socket
> +
> +[Socket]
> +ListenStream=@runstatedir@/libvirt/@sockprefix@-admin-sock
> +Service=@service@.service
> +SocketMode=0600
> +
> +[Install]
> +WantedBy=sockets.target
> diff --git a/src/virtd-ro.socket.in b/src/virtd-ro.socket.in
> new file mode 100644
> index 0000000000..b7b7ae0dd8
> --- /dev/null
> +++ b/src/virtd-ro.socket.in
> @@ -0,0 +1,13 @@
> +[Unit]
> +Description=@name@ local read-only socket
> +Before=@service@.service
> +BindsTo=@service@.socket
> +After=@service@.socket
> +
> +[Socket]
> +ListenStream=@runstatedir@/libvirt/@sockprefix@-sock-ro
> +Service=@service@.service
> +SocketMode=0666
> +
> +[Install]
> +WantedBy=sockets.target
> diff --git a/src/virtd-tcp.socket.in b/src/virtd-tcp.socket.in
> new file mode 100644
> index 0000000000..7c8bcdb525
> --- /dev/null
> +++ b/src/virtd-tcp.socket.in
> @@ -0,0 +1,12 @@
> +[Unit]
> +Description=@name@ non-TLS IP socket
> +Before=@service@.service
> +BindsTo=@service@.socket
> +After=@service@.socket
> +
> +[Socket]
> +ListenStream=16509
> +Service=@service@.service
> +
> +[Install]
> +WantedBy=sockets.target
> diff --git a/src/virtd-tls.socket.in b/src/virtd-tls.socket.in
> new file mode 100644
> index 0000000000..c6dceb2d4e
> --- /dev/null
> +++ b/src/virtd-tls.socket.in
> @@ -0,0 +1,12 @@
> +[Unit]
> +Description=@name@ TLS IP socket
> +Before=@service@.service
> +BindsTo=@service@.socket
> +After=@service@.socket
> +
> +[Socket]
> +ListenStream=16514
> +Service=@service@.service
> +
> +[Install]
> +WantedBy=sockets.target
> diff --git a/src/virtd.service.in b/src/virtd.service.in
> new file mode 100644
> index 0000000000..76f9c60351
> --- /dev/null
> +++ b/src/virtd.service.in
> @@ -0,0 +1,25 @@
> +[Unit]
> +Description=@name@ daemon
> +Conflicts=libvirtd.service
> +Requires=@service@.socket
> +Requires=@service@-ro.socket
> +Requires=@service@-admin.socket
> +After=network.target
> +After=dbus.service
> +After=apparmor.service
> +Documentation=man:@service@(8)
> +Documentation=https://libvirt.org
> +
> +[Service]
> +Type=notify
> +Environment=@SERVICE@_ARGS="--timeout 120"
> +EnvironmentFile=-@initconfdir@/@service@
> +ExecStart=@sbindir@/@service@ $@SERVICE@_ARGS
> +ExecReload=/bin/kill -HUP $MAINPID
> +Restart=on-failure
> +
> +[Install]
> +WantedBy=multi-user.target
> +Also=@service@.socket
> +Also=@service@-ro.socket
> +Also=@service@-admin.socket
> diff --git a/src/virtd.socket.in b/src/virtd.socket.in
> new file mode 100644
> index 0000000000..aec0708fd4
> --- /dev/null
> +++ b/src/virtd.socket.in
> @@ -0,0 +1,12 @@
> +[Unit]
> +Description=@name@ local socket
> +Before=@service@.service
> +
> +[Socket]
> +ListenStream=@runstatedir@/libvirt/@sockprefix@-sock
> +Service=@service@.service
> +SocketMode=@sockmode@
> +RemoveOnStop=yes
> +
> +[Install]
> +WantedBy=sockets.target
> --
> 2.41.0
>
With regards,
Daniel
--
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