system display: T2564 Extend VyOS to support appliance LCDs

Added support for system LCDs under CLI system display

+data/templates/system-display/LCDd.conf.tmpl template for LCDd server configuration file
+data/templates/system-display/lcdproc.conf.tmpl template for lcdproc client configuration file
+interface-definitions/system-display.xml.in CLI for system display
+src/conf_mode/system-display.py processing code for system display
+src/systemd/lcdproc.service systemd service definition file for lcdproc client

CLI:
    system display model (SDEC|EZIO)
    system display config (enabled|disabled)
    system display show host (cpu|cpu-all|cpu-hist|disk|load-hist|memory|proc|uptime)
                        network interface <intName> alias <alias>
                                units (bps|Bps|pps)
                        clock (big|mini|date-time)
                        title <name>

    system display duration <s>
    system display hello <string>
    system display bye <string>

1 files changed, 92 insertions, 0 deletions

diff --git a/src/conf_mode/system-display.py b/src/conf_mode/system-display.py
new file mode 100755
index 000000000..4db375d8e
--- /dev/null
+++ b/src/conf_mode/system-display.py
@@ -0,0 +1,92 @@
+#!/usr/bin/env python3
+#
+# Copyright (C) 2020 Francois Mertz fireboxled at gmail.com
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License version 2 or later as
+# published by the Free Software Foundation.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+import os
+import re
+
+from sys import exit
+
+from vyos.config import Config
+from vyos import ConfigError
+from vyos.util import run
+from vyos.template import render
+
+from vyos import airbag
+airbag.enable()
+
+def get_config():
+    c = Config()
+
+    if not c.exists('system display'):
+        return None
+
+    c.set_level('system display')
+
+    return c.get_config_dict([])
+
+def generate(c):
+    if c == None:
+        return None
+    # Render config file for daemon LCDd
+    render('/etc/LCDd.conf', 'system-display/LCDd.conf.tmpl', c)
+    # Render config file for client lcdproc
+    render('/etc/lcdproc.conf', 'system-display/lcdproc.conf.tmpl', c)
+
+    return None
+
+def verify(c):
+    if c == None:
+        return None
+
+    if c.get('model') == None:
+        raise ConfigError('For system display, a model is [REQUIRED]')
+
+    if c.get('show') == None:
+        raise ConfigError('For system display, show cannot be empty')
+
+    if 'network' in c['show'] and 'interface' not in c['show']['network']:
+        raise ConfigError('system display show network must have at least one interface')
+
+    if 'network' in c['show'] and 'interface' in c['show']['network'] and len(c['show']['network']['interface']) > 3:
+        raise ConfigError('system display show network interface cannot have more than 3 entries')
+
+    return None
+
+def apply(c):
+    if not c or c['config'] == 'disabled':
+        # Stop client first
+        run('systemctl stop lcdproc.service')
+        # Stop server next
+        return run('systemctl stop LCDd.service')
+
+    # Stop client first
+    run('systemctl stop lcdproc.service')
+    # Restart server next
+    run('systemctl restart LCDd.service')
+    # Start client
+    run('systemctl start lcdproc.service')
+
+    return None
+
+if __name__ == '__main__':
+    try:
+        c = get_config()
+        verify(c)
+        generate(c)
+        apply(c)
+    except ConfigError as e:
+        print(e)
+        exit(1)