T5222: Add load-balancing for web traffic

1 files changed, 182 insertions, 0 deletions

diff --git a/src/conf_mode/load-balancing-haproxy.py b/src/conf_mode/load-balancing-haproxy.py
new file mode 100755
index 000000000..d2b895fbe
--- /dev/null
+++ b/src/conf_mode/load-balancing-haproxy.py
@@ -0,0 +1,182 @@
+#!/usr/bin/env python3
+#
+# Copyright (C) 2023 VyOS maintainers and contributors
+#
+# 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
+
+from sys import exit
+from shutil import rmtree
+
+from vyos.config import Config
+from vyos.configdict import dict_merge
+from vyos.util import call
+from vyos.util import check_port_availability
+from vyos.util import is_listen_port_bind_service
+from vyos.pki import wrap_certificate
+from vyos.pki import wrap_private_key
+from vyos.template import render
+from vyos.xml import defaults
+from vyos import ConfigError
+from vyos import airbag
+airbag.enable()
+
+load_balancing_dir = '/run/haproxy'
+load_balancing_conf_file = f'{load_balancing_dir}/haproxy.cfg'
+systemd_service = 'haproxy.service'
+systemd_override = r'/run/systemd/system/haproxy.service.d/10-override.conf'
+
+
+def get_config(config=None):
+    if config:
+        conf = config
+    else:
+        conf = Config()
+
+    base = ['load-balancing', 'reverse-proxy']
+    lb = conf.get_config_dict(base,
+                              get_first_key=True,
+                              key_mangling=('-', '_'),
+                              no_tag_node_value_mangle=True)
+
+    if lb:
+        lb['pki'] = conf.get_config_dict(['pki'], key_mangling=('-', '_'),
+                                    get_first_key=True, no_tag_node_value_mangle=True)
+
+    # We have gathered the dict representation of the CLI, but there are default
+    # options which we need to update into the dictionary retrived.
+    default_values = defaults(base)
+    if 'backend' in default_values:
+        del default_values['backend']
+    if lb:
+        lb = dict_merge(default_values, lb)
+
+    if 'backend' in lb:
+        for backend in lb['backend']:
+            default_balues_backend = defaults(base + ['backend'])
+            lb['backend'][backend] = dict_merge(default_balues_backend, lb['backend'][backend])
+
+    return lb
+
+
+def verify(lb):
+    if not lb:
+        return None
+
+    if 'backend' not in lb or 'server' not in lb:
+        raise ConfigError(f'"server" and "backend" must be configured!')
+
+    for front, front_config in lb['server'].items():
+        if 'port' not in front_config:
+            raise ConfigError(f'"{front} server port" must be configured!')
+        # We can use redirect to HTTPS without backend section
+        if 'backend' not in front_config and 'redirect_http_to_https' not in front_config:
+           raise ConfigError(f'"{front} backend" must be configured!')
+
+        # Check if bind address:port are used by another service
+        tmp_address = front_config.get('address', '0.0.0.0')
+        tmp_port = front_config['port']
+        if check_port_availability(tmp_address, int(tmp_port), 'tcp') is not True and \
+                not is_listen_port_bind_service(int(tmp_port), 'haproxy'):
+            raise ConfigError(f'"TCP" port "{tmp_port}" is used by another service')
+
+    for back, back_config in lb['backend'].items():
+        if 'server' not in back_config:
+            raise ConfigError(f'"{back} server" must be configured!')
+        for bk_server, bk_server_conf in back_config['server'].items():
+            if 'address' not in bk_server_conf or 'port' not in bk_server_conf:
+                raise ConfigError(f'"backend {back} server {bk_server} address and port" must be configured!')
+
+
+def generate(lb):
+    if not lb:
+        # Delete /run/haproxy/haproxy.cfg
+        config_files = [load_balancing_conf_file, systemd_override]
+        for file in config_files:
+            if os.path.isfile(file):
+                os.unlink(file)
+        # Delete old directories
+        #if os.path.isdir(load_balancing_dir):
+        #    rmtree(load_balancing_dir, ignore_errors=True)
+
+        return None
+
+    # Create load-balance dir
+    if not os.path.isdir(load_balancing_dir):
+        os.mkdir(load_balancing_dir)
+
+    # SSL Certificates for frontend
+    for front, front_config in lb['server'].items():
+        if 'ssl' in front_config:
+            cert_file_path = os.path.join(load_balancing_dir, 'cert.pem')
+            cert_key_path = os.path.join(load_balancing_dir, 'cert.pem.key')
+            ca_cert_file_path = os.path.join(load_balancing_dir, 'ca.pem')
+
+            if 'certificate' in front_config['ssl']:
+                #cert_file_path = os.path.join(load_balancing_dir, 'cert.pem')
+                #cert_key_path = os.path.join(load_balancing_dir, 'cert.key')
+                cert_name = front_config['ssl']['certificate']
+                pki_cert = lb['pki']['certificate'][cert_name]
+
+                with open(cert_file_path, 'w') as f:
+                    f.write(wrap_certificate(pki_cert['certificate']))
+
+                if 'private' in pki_cert and 'key' in pki_cert['private']:
+                    with open(cert_key_path, 'w') as f:
+                        f.write(wrap_private_key(pki_cert['private']['key']))
+
+            if 'ca_certificate' in front_config['ssl']:
+                ca_name = front_config['ssl']['ca_certificate']
+                pki_ca_cert = lb['pki']['ca'][ca_name]
+
+                with open(ca_cert_file_path, 'w') as f:
+                    f.write(wrap_certificate(pki_ca_cert['certificate']))
+
+    # SSL Certificates for backend
+    for back, back_config in lb['backend'].items():
+        if 'ssl' in back_config:
+            ca_cert_file_path = os.path.join(load_balancing_dir, 'ca.pem')
+
+            if 'ca_certificate' in back_config['ssl']:
+                ca_name = back_config['ssl']['ca_certificate']
+                pki_ca_cert = lb['pki']['ca'][ca_name]
+
+                with open(ca_cert_file_path, 'w') as f:
+                    f.write(wrap_certificate(pki_ca_cert['certificate']))
+
+    render(load_balancing_conf_file, 'load-balancing/haproxy.cfg.j2', lb)
+    render(systemd_override, 'load-balancing/override_haproxy.conf.j2', lb)
+
+    return None
+
+
+def apply(lb):
+    call('systemctl daemon-reload')
+    if not lb:
+        call(f'systemctl stop {systemd_service}')
+    else:
+        call(f'systemctl reload-or-restart {systemd_service}')
+
+    return None
+
+
+if __name__ == '__main__':
+    try:
+        c = get_config()
+        verify(c)
+        generate(c)
+        apply(c)
+    except ConfigError as e:
+        print(e)
+        exit(1)