# octavia.amphorae.backends.agent.api_server.loadbalancer

# Source code for octavia.amphorae.backends.agent.api_server.loadbalancer

    # Copyright 2015 Hewlett-Packard Development Company, L.P.
    #
    # Licensed under the Apache License, Version 2.0 (the "License"); you may
    # not use this file except in compliance with the License. You may obtain
    # a copy of the License at
    #
    # http://www.apache.org/licenses/LICENSE-2.0
    #
    # Unless required by applicable law or agreed to in writing, software
    # distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
    # WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
    # License for the specific language governing permissions and limitations
    # under the License.

    import hashlib
    import io
    import os
    import re
    import shutil
    import stat
    import subprocess
    import time

    import flask
    import jinja2
    from oslo_config import cfg
    from oslo_log import log as logging
    import webob
    from werkzeug import exceptions

    from octavia.amphorae.backends.agent.api_server import haproxy_compatibility
    from octavia.amphorae.backends.agent.api_server import util
    from octavia.amphorae.backends.utils import haproxy_query
    from octavia.common import constants as consts
    from octavia.common import utils as octavia_utils

    LOG = logging.getLogger(__name__)
    BUFFER = 100
    HAPROXY_RELOAD_RETRIES = 3
    HAPROXY_QUERY_RETRIES = 5

    CONF = cfg.CONF

    SYSTEMD_CONF = 'systemd.conf.j2'

    JINJA_ENV = jinja2.Environment(
        autoescape=True,
        loader=jinja2.FileSystemLoader(os.path.dirname(
            os.path.realpath(__file__)
        ) + consts.AGENT_API_TEMPLATES))
    SYSTEMD_TEMPLATE = JINJA_ENV.get_template(SYSTEMD_CONF)

    # Wrap a stream so we can compute the md5 while reading

    class Wrapped:
        def __init__(self, stream_):
            self.stream = stream_
            self.hash = hashlib.md5(usedforsecurity=False)  # nosec

        def read(self, line):
            block = self.stream.read(line)
            if block:
                self.hash.update(block)
            return block

        def get_md5(self):
            return self.hash.hexdigest()

        def __getattr__(self, attr):
            return getattr(self.stream, attr)

    class Loadbalancer:

        def get_haproxy_config(self, lb_id):
            """Gets the haproxy config

            :param listener_id: the id of the listener
            """
            self._check_lb_exists(lb_id)
            with open(util.config_path(lb_id), encoding='utf-8') as file:
                cfg = file.read()
                resp = webob.Response(cfg, content_type='text/plain')
                resp.headers['ETag'] = (
                    hashlib.md5(octavia_utils.b(cfg),
                                usedforsecurity=False).hexdigest())  # nosec
                return resp

        def upload_haproxy_config(self, amphora_id, lb_id):
            """Upload the haproxy config

            :param amphora_id: The id of the amphora to update
            :param lb_id: The id of the loadbalancer
            """
            stream = Wrapped(flask.request.stream)
            # We have to hash here because HAProxy has a string length limitation
            # in the configuration file "peer <peername>" lines
            peer_name = octavia_utils.base64_sha1_string(amphora_id).rstrip('=')
            if not os.path.exists(util.haproxy_dir(lb_id)):
                os.makedirs(util.haproxy_dir(lb_id))

            name = os.path.join(util.haproxy_dir(lb_id), 'haproxy.cfg.new')
            flags = os.O_WRONLY | os.O_CREAT | os.O_TRUNC
            # mode 00600
            mode = stat.S_IRUSR | stat.S_IWUSR
            b = stream.read(BUFFER)
            s_io = io.StringIO()
            while b:
                # Write haproxy configuration to StringIO
                s_io.write(b.decode('utf8'))
                b = stream.read(BUFFER)

            # Since haproxy user_group is now auto-detected by the amphora agent,
            # remove it from haproxy configuration in case it was provided
            # by an older Octavia controller. This is needed in order to prevent
            # a duplicate entry for 'group' in haproxy configuration, which will
            # result an error when haproxy starts.
            new_config = re.sub(r"\s+group\s.+", "", s_io.getvalue())

            # Handle any haproxy version compatibility issues
            new_config = haproxy_compatibility.process_cfg_for_version_compat(
                new_config)

            with os.fdopen(os.open(name, flags, mode), 'w') as file:
                file.write(new_config)

            # use haproxy to check the config
            cmd = (f"haproxy -c -L {peer_name} -f {name} -f "
                   f"{consts.HAPROXY_USER_GROUP_CFG}")

            try:
                subprocess.check_output(cmd.split(), stderr=subprocess.STDOUT,
                                        encoding='utf-8')
            except subprocess.CalledProcessError as e:
                LOG.error("Failed to verify haproxy file: %s %s", e, e.output)
                # Save the last config that failed validation for debugging
                os.rename(name, ''.join([name, '-failed']))
                return webob.Response(
                    json={'message': "Invalid request", 'details': e.output},
                    status=400)

            # file ok - move it
            os.rename(name, util.config_path(lb_id))

            init_path = util.init_path(lb_id)

            template = SYSTEMD_TEMPLATE
            # Render and install the network namespace systemd service
            util.install_netns_systemd_service()
            util.run_systemctl_command(
                consts.ENABLE, consts.AMP_NETNS_SVC_PREFIX + '.service', False)

            # mode 00644
            mode = stat.S_IRUSR | stat.S_IWUSR | stat.S_IRGRP | stat.S_IROTH

            hap_major, hap_minor = haproxy_compatibility.get_haproxy_versions()
            if not os.path.exists(init_path):
                with os.fdopen(os.open(init_path, flags, mode), 'w') as text_file:

                    text = template.render(
                        peer_name=peer_name,
                        haproxy_pid=util.pid_path(lb_id),
                        haproxy_cmd=util.CONF.haproxy_amphora.haproxy_cmd,
                        haproxy_cfg=util.config_path(lb_id),
                        haproxy_state_file=util.state_file_path(lb_id),
                        haproxy_socket=util.haproxy_sock_path(lb_id),
                        haproxy_user_group_cfg=consts.HAPROXY_USER_GROUP_CFG,
                        amphora_netns=consts.AMP_NETNS_SVC_PREFIX,
                        amphora_nsname=consts.AMPHORA_NAMESPACE,
                        haproxy_major_version=hap_major,
                        haproxy_minor_version=hap_minor
                    )
                    text_file.write(text)

            # Make sure the new service is enabled on boot
            try:
                util.run_systemctl_command(
                    consts.ENABLE, consts.LOADBALANCER_SYSTEMD % lb_id)
            except subprocess.CalledProcessError as e:
                return webob.Response(json={
                    'message': "Error enabling octavia-keepalived service",
                    'details': e.output}, status=500)

            res = webob.Response(json={'message': 'OK'}, status=202)
            res.headers['ETag'] = stream.get_md5()

            return res

        def _check_haproxy_uptime(self, lb_id):
            stat_sock_file = util.haproxy_sock_path(lb_id)
            lb_query = haproxy_query.HAProxyQuery(stat_sock_file)
            retries = HAPROXY_QUERY_RETRIES
            for idx in range(retries):
                try:
                    info = lb_query.show_info()
                    uptime_sec = info['Uptime_sec']
                except Exception as e:
                    LOG.warning('Failed to get haproxy info: %s, retrying.', e)
                    time.sleep(1)
                    continue
                uptime = int(uptime_sec)
                return uptime
            LOG.error('Failed to get haproxy uptime after %d tries.', retries)
            return None

        def start_stop_lb(self, lb_id, action):
            action = action.lower()
            if action not in [consts.AMP_ACTION_START,
                              consts.AMP_ACTION_STOP,
                              consts.AMP_ACTION_RELOAD]:
                return webob.Response(json={
                    'message': 'Invalid Request',
                    'details': f"Unknown action: {action}"}, status=400)

            self._check_lb_exists(lb_id)
            is_vrrp = (CONF.controller_worker.loadbalancer_topology ==
                       consts.TOPOLOGY_ACTIVE_STANDBY)

            if is_vrrp:
                util.vrrp_check_script_update(lb_id, action)

            # HAProxy does not start the process when given a reload
            # so start it if haproxy is not already running
            if action == consts.AMP_ACTION_RELOAD:
                if consts.OFFLINE == self._check_haproxy_status(lb_id):
                    action = consts.AMP_ACTION_START
                else:
                    # We first have to save the state when we reload
                    haproxy_state_file = util.state_file_path(lb_id)
                    stat_sock_file = util.haproxy_sock_path(lb_id)

                    lb_query = haproxy_query.HAProxyQuery(stat_sock_file)
                    if not lb_query.save_state(haproxy_state_file):
                        # We accept to reload haproxy even if the state_file is
                        # not generated, but we probably want to know about that
                        # failure!
                        LOG.warning('Failed to save haproxy-%s state!', lb_id)

            retries = (HAPROXY_RELOAD_RETRIES
                       if action == consts.AMP_ACTION_RELOAD
                       else 1)
            saved_exc = None
            for idx in range(retries):
                try:
                    util.run_systemctl_command(
                        action, consts.LOADBALANCER_SYSTEMD % lb_id)
                except subprocess.CalledProcessError as e:
                    # Mitigation for
                    # https://bugs.launchpad.net/octavia/+bug/2054666
                    if ('is not active, cannot reload.' in e.output and
                            action == consts.AMP_ACTION_RELOAD):

                        saved_exc = e

                        # Wait a few seconds and check that haproxy was restarted
                        uptime = self._check_haproxy_uptime(lb_id)
                        # If haproxy is not reachable or was restarted more than 15
                        # sec ago, let's retry (or maybe restart?)
                        if not uptime or uptime > 15:
                            continue
                        # haproxy probably crashed and was restarted, log it and
                        # continue
                        LOG.warning("An error occured with haproxy while it "
                                    "was reloaded, check the haproxy logs for "
                                    "more details.")
                        break
                    if 'Job is already running' not in e.output:
                        return webob.Response(json={
                            'message': f"Error {action}ing haproxy",
                            'details': e.output
                        }, status=500)
                break
            else:
                # no break, we reach the retry limit for reloads
                return webob.Response(json={
                    'message': f"Error {action}ing haproxy",
                    'details': saved_exc.output}, status=500)

            # If we are not in active/standby we need to send an IP
            # advertisement (GARP or NA). Keepalived handles this for
            # active/standby load balancers.
            if not is_vrrp and action in [consts.AMP_ACTION_START,
                                          consts.AMP_ACTION_RELOAD]:
                util.send_vip_advertisements(lb_id)

            if action in [consts.AMP_ACTION_STOP,
                          consts.AMP_ACTION_RELOAD]:
                return webob.Response(json={
                    'message': 'OK',
                    'details': f'Listener {lb_id} {action}ed'}, status=202)

            details = (
                f'Configuration file is valid\nhaproxy daemon for {lb_id} started'
            )

            return webob.Response(json={'message': 'OK', 'details': details},
                                  status=202)

        def delete_lb(self, lb_id):
            try:
                self._check_lb_exists(lb_id)
            except exceptions.HTTPException:
                return webob.Response(json={'message': 'OK'})

            # check if that haproxy is still running and if stop it
            if os.path.exists(util.pid_path(lb_id)) and os.path.exists(
                    os.path.join('/proc', util.get_haproxy_pid(lb_id))):
                try:
                    util.run_systemctl_command(
                        consts.STOP, consts.LOADBALANCER_SYSTEMD % lb_id)
                except subprocess.CalledProcessError as e:
                    LOG.error("Failed to stop haproxy-%s service: %s %s",
                              lb_id, e, e.output)
                    return webob.Response(json={
                        'message': "Error stopping haproxy",
                        'details': e.output}, status=500)

            # parse config and delete stats socket
            try:
                stats_socket = util.parse_haproxy_file(lb_id)[0]
                os.remove(stats_socket)
            except Exception:
                pass

            # Since this script should be deleted at LB delete time
            # we can check for this path to see if VRRP is enabled
            # on this amphora and not write the file if VRRP is not in use
            if os.path.exists(util.keepalived_check_script_path()):
                util.vrrp_check_script_update(
                    lb_id, action=consts.AMP_ACTION_STOP)

            # delete the ssl files
            try:
                shutil.rmtree(self._cert_dir(lb_id))
            except Exception:
                pass

            # disable the service
            init_path = util.init_path(lb_id)

            util.run_systemctl_command(
                consts.DISABLE, consts.LOADBALANCER_SYSTEMD % lb_id, False)

            # delete the directory + init script for that listener
            shutil.rmtree(util.haproxy_dir(lb_id))
            if os.path.exists(init_path):
                os.remove(init_path)

            return webob.Response(json={'message': 'OK'})

        def get_all_listeners_status(self, other_listeners=None):
            """Gets the status of all listeners

            This method will not consult the stats socket
            so a listener might show as ACTIVE but still be
            in ERROR

            Currently type==SSL is also not detected
            """
            listeners = []

            for lb in util.get_loadbalancers():
                stats_socket, listeners_on_lb = util.parse_haproxy_file(lb)

                for listener_id, listener in listeners_on_lb.items():
                    listeners.append({
                        'status': consts.ACTIVE,
                        'uuid': listener_id,
                        'type': listener['mode'],
                    })

            if other_listeners:
                listeners = listeners + other_listeners
            return webob.Response(json=listeners, content_type='application/json')

        def upload_certificate(self, lb_id, filename):
            self._check_ssl_filename_format(filename)

            # create directory if not already there
            if not os.path.exists(self._cert_dir(lb_id)):
                os.makedirs(self._cert_dir(lb_id))

            stream = Wrapped(flask.request.stream)
            file = self._cert_file_path(lb_id, filename)
            flags = os.O_WRONLY | os.O_CREAT | os.O_TRUNC
            # mode 00600
            mode = stat.S_IRUSR | stat.S_IWUSR
            with os.fdopen(os.open(file, flags, mode), 'wb') as crt_file:
                b = stream.read(BUFFER)
                while b:
                    crt_file.write(b)
                    b = stream.read(BUFFER)

            resp = webob.Response(json={'message': 'OK'})
            resp.headers['ETag'] = stream.get_md5()
            return resp

        def get_certificate_md5(self, lb_id, filename):
            self._check_ssl_filename_format(filename)

            cert_path = self._cert_file_path(lb_id, filename)
            path_exists = os.path.exists(cert_path)
            if not path_exists:
                return webob.Response(json={
                    'message': 'Certificate Not Found',
                    'details': f"No certificate with filename: {filename}"},
                    status=404)

            with open(cert_path, encoding='utf-8') as crt_file:
                cert = crt_file.read()
                md5sum = hashlib.md5(octavia_utils.b(cert),
                                     usedforsecurity=False).hexdigest()  # nosec
                resp = webob.Response(json={'md5sum': md5sum})
                resp.headers['ETag'] = md5sum
                return resp

        def delete_certificate(self, lb_id, filename):
            self._check_ssl_filename_format(filename)
            if os.path.exists(self._cert_file_path(lb_id, filename)):
                os.remove(self._cert_file_path(lb_id, filename))
            return webob.Response(json={'message': 'OK'})

        def _get_listeners_on_lb(self, lb_id):
            if os.path.exists(util.pid_path(lb_id)):
                if os.path.exists(
                        os.path.join('/proc', util.get_haproxy_pid(lb_id))):
                    # Check if the listener is disabled
                    with open(util.config_path(lb_id), encoding='utf-8') as file:
                        cfg = file.read()
                        m = re.findall('^frontend (.*)$', cfg, re.MULTILINE)
                        return m or []
                else:  # pid file but no process...
                    return []
            else:
                return []

        def _check_lb_exists(self, lb_id):
            # check if we know about that lb
            if lb_id not in util.get_loadbalancers():
                raise exceptions.HTTPException(
                    response=webob.Response(json={
                        'message': 'Loadbalancer Not Found',
                        'details': f"No loadbalancer with UUID: {lb_id}"},
                        status=404))

        def _check_ssl_filename_format(self, filename):
            # check if the format is (xxx.)*xxx.pem
            if not re.search(r'(\w.)+pem', filename):
                raise exceptions.HTTPException(
                    response=webob.Response(json={
                        'message': 'Filename has wrong format'}, status=400))

        def _cert_dir(self, lb_id):
            return os.path.join(util.CONF.haproxy_amphora.base_cert_dir, lb_id)

        def _cert_file_path(self, lb_id, filename):
            return os.path.join(self._cert_dir(lb_id), filename)

        def _check_haproxy_status(self, lb_id):
            if os.path.exists(util.pid_path(lb_id)):
                if os.path.exists(
                        os.path.join('/proc', util.get_haproxy_pid(lb_id))):
                    return consts.ACTIVE
            return consts.OFFLINE

this page last updated: 2025-04-03 17:35:57

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