Add support for HAProxy L7 checks

This change add several configuration options to enable HTTP checks
to the HAProxy configuration, instead of the default TCP connection
checks (which continue to be the default). It also enables /healthcheck
endpoint for cinder-api on openstack releases >= ocata.

Closes-Bug: #1880610
Change-Id: I9d118f70fc1390be7b800ad20ae20e77818adac7

hooks/cinder_contexts.py

@@ -36,6 +36,7 @@ from charmhelpers.contrib.openstack.utils import (
 from charmhelpers.contrib.hahelpers.cluster import (
     determine_apache_port,
     determine_api_port,
+    https
 )
 
 CHARM_CEPH_CONF = '/var/lib/charm/{}/ceph.conf'
@@ -100,16 +101,26 @@ class HAProxyContext(OSContextGenerator):
         specific to this charm.
         Also used to extend cinder.conf context with correct api_listening_port
         '''
+        service = 'cinder_api'
         haproxy_port = config('api-listening-port')
         api_port = determine_api_port(config('api-listening-port'),
                                       singlenode_mode=True)
         apache_port = determine_apache_port(config('api-listening-port'),
                                             singlenode_mode=True)
 
+        backend_options = {
+            service: [{
+                'option': 'httpchk GET /healthcheck',
+                'http-check': 'expect status 200',
+            }]
+        }
+
         ctxt = {
-            'service_ports': {'cinder_api': [haproxy_port, apache_port]},
+            'service_ports': {service: [haproxy_port, apache_port]},
             'osapi_volume_listen_port': api_port,
             'port': api_port,
+            'backend_options': backend_options,
+            'https': https()
         }
         return ctxt
 

templates/ocata/api-paste.ini

@@ -5,6 +5,7 @@
 [composite:osapi_volume]
 use = call:cinder.api:root_app_factory
 /: apiversions
+/healthcheck: healthcheck
 /v1: openstack_volume_api_v1
 /v2: openstack_volume_api_v2
 /v3: openstack_volume_api_v3
@@ -64,6 +65,14 @@ pipeline = cors http_proxy_to_wsgi faultwrap osvolumeversionapp
 [app:osvolumeversionapp]
 paste.app_factory = cinder.api.versions:Versions.factory
 
+[pipeline:healthcheck]
+pipeline = request_id healthcheckapp
+
+[app:healthcheckapp]
+paste.app_factory = oslo_middleware:Healthcheck.app_factory
+backends = disable_by_file
+disable_by_file_path = /etc/cinder/healthcheck_disable
+
 ##########
 # Shared #
 ##########

tox.ini

@@ -25,7 +25,7 @@ setenv = VIRTUAL_ENV={envdir}
 commands = stestr run --slowest {posargs}
 allowlist_externals =
     charmcraft
-    rename.sh
+    {toxinidir}/rename.sh
 passenv =
     HOME
     TERM

unit_tests/test_cinder_contexts.py

@@ -26,8 +26,6 @@ TO_PATCH = [
     'config',
     'relation_ids',
     'service_name',
-    'determine_apache_port',
-    'determine_api_port',
     'os_release',
     'related_units',
     'relation_get'
@@ -545,3 +543,32 @@ class TestCinderContext(CharmTestCase):
             contexts.VolumeUsageAuditContext.DEFAULT_CRONTAB_PATH, "wt+")
         self.assertEqual(self.config.return_value,
                          ctxt["volume_usage_audit_period"])
+
+    @patch('charmhelpers.contrib.hahelpers.cluster.https')
+    @patch('cinder_contexts.https')
+    def test_haproxy_context(self, mock_https, mock_ch_https):
+        config = {'api-listening-port': 8776}
+        self.config.side_effect = lambda x: config[x]
+        for https_mode in [False, True]:
+            mock_https.return_value = https_mode
+            mock_ch_https.return_value = https_mode
+            api_port = 8766
+            if https_mode:
+                api_port = 8756
+
+            haproxy_context = contexts.HAProxyContext()
+            expected = {
+                "service_ports": {"cinder_api": [8776, 8766]},
+                "osapi_volume_listen_port": api_port,
+                'port': api_port,
+                "backend_options": {
+                    "cinder_api": [
+                        {
+                            'option': 'httpchk GET /healthcheck',
+                            'http-check': 'expect status 200',
+                        }
+                    ]
+                },
+                "https": https_mode,
+            }
+            self.assertEqual(expected, haproxy_context())