Merge ~nick-moffitt/content-cache-charm:monitoring into content-cache-charm:master

[Nick Moffitt]

Add support for telegraf LP#1824568

[Tom Haddon (mthaddon)]

One comment inline

[🤖 Canonical IS Merge Bot (canonical-is-mergebot)]

This merge proposal is being monitored by mergebot. Change the status to Approved to merge.

[Tom Haddon (mthaddon)]

LGTM

review: Approve

[🤖 Canonical IS Merge Bot (canonical-is-mergebot)]

Change successfully merged at revision ec50bf6d44c864aba264f1c58eb8ef4f698089b0

diff --git a/lib/haproxy.py b/lib/haproxy.py
index 7ab1e74..38509a1 100644
--- a/lib/haproxy.py
+++ b/lib/haproxy.py
@@ -1,6 +1,7 @@
 import datetime
 import multiprocessing
 import os
+import re
 
 import jinja2
 
@@ -24,6 +25,18 @@ class HAProxyConf:
     def conf_file(self):
         return os.path.join(self._conf_path, 'haproxy.cfg')
 
+    @property
+    def monitoring_password(self):
+        try:
+            with open(self.conf_file, 'r') as f:
+                m = re.search(r"stats auth\s+(\w+):(\w+)", f.read())
+                if m is not None:
+                    return m.group(2)
+                else:
+                    return None
+        except FileNotFoundError:
+            return None
+
     def _generate_stanza_name(self, name, exclude=None):
         if exclude is None:
             exclude = []
@@ -159,7 +172,7 @@ backend backend-{name}
 
         return rendered_output
 
-    def render(self, config, num_procs=None):
+    def render(self, config, num_procs=None, monitoring_password=None):
         if not num_procs:
             num_procs = multiprocessing.cpu_count()
 
@@ -170,6 +183,7 @@ backend backend-{name}
             'listen': self.render_stanza_listen(config),
             'backend': self.render_stanza_backend(config),
             'num_procs': num_procs,
+            'monitoring_password': monitoring_password or self.monitoring_password,
         })
 
     def write(self, content):
diff --git a/metadata.yaml b/metadata.yaml
index ceba5c2..a3b5a01 100644
--- a/metadata.yaml
+++ b/metadata.yaml
@@ -17,3 +17,6 @@ provides:
   nrpe-external-master:
     interface: nrpe-external-master
     scope: container
+  haproxy-statistics:
+    interface: statistics
+    scope: container
diff --git a/reactive/content_cache.py b/reactive/content_cache.py
index 460f120..01c2c95 100644
--- a/reactive/content_cache.py
+++ b/reactive/content_cache.py
@@ -7,6 +7,7 @@ from copy import deepcopy
 
 from charms import reactive
 from charms.layer import status
+from charmhelpers import context
 from charmhelpers.core import hookenv, host
 from charmhelpers.contrib.charmsupport import nrpe
 
@@ -33,6 +34,12 @@ def upgrade_charm():
         reactive.set_flag('nrpe-external-master.available')
 
 
[e-mail]('haproxy-statistics-relation-joined', 'haproxy-statistics-relation-changed')
+def fire_stats_hook():
+    """We don't have an interface for this relation yet, so just fake it here."""
+    reactive.set_flag('haproxy-statistics.available')
+
+
 @reactive.when_not('content_cache.installed')
 def install():
     reactive.clear_flag('content_cache.active')
@@ -218,7 +225,12 @@ def configure_haproxy():
             if not new_conf[cached_site]['locations']:
                 new_conf[cached_site]['locations'][location] = new_cached_loc_conf
 
-    if haproxy.write(haproxy.render(new_conf)):
+    if haproxy.monitoring_password:
+        rendered_config = haproxy.render(new_conf, monitoring_password=haproxy.monitoring_password)
+    else:
+        rendered_config = haproxy.render(new_conf, monitoring_password=host.pwgen(length=20))
+
+    if haproxy.write(rendered_config):
         service_start_or_restart('haproxy')
 
     reactive.set_flag('content_cache.haproxy.configured')
@@ -309,6 +321,19 @@ def configure_nagios():
     reactive.set_flag('nagios-nrpe.configured')
 
 
[e-mail]('content_cache.haproxy.configured')
[e-mail]('haproxy-statistics.available')
+def advertise_stats_endpoint():
+    rels = context.Relations()
+    password = HAProxy.HAProxyConf().monitoring_password
+
+    for rel in rels['haproxy-statistics'].values():
+        rel.local['enabled'] = "True"
+        rel.local['port'] = "10000"
+        rel.local['user'] = "haproxy"
+        rel.local['password'] = password
+
+
 def sites_from_config(sites_yaml, sites_secrets=None):
     conf = yaml.safe_load(sites_yaml)
     sites = interpolate_secrets(conf, sites_secrets)
diff --git a/templates/haproxy_cfg.tmpl b/templates/haproxy_cfg.tmpl
index 0786d83..df8f083 100644
--- a/templates/haproxy_cfg.tmpl
+++ b/templates/haproxy_cfg.tmpl
@@ -39,6 +39,18 @@ defaults
 	errorfile 503 /etc/haproxy/errors/503.http
 	errorfile 504 /etc/haproxy/errors/504.http
 
+listen  stats
+	bind 127.0.0.1:10000
+	acl allowed_cidr src 127.0.0.0/8
+	http-request deny unless allowed_cidr
+
+	mode http
+	stats enable
+	stats uri /
+	stats realm Haproxy\ Statistics
+	stats auth haproxy:{{monitoring_password}}
+	stats refresh 3
+
 {% for stanza in listen -%}
 {{stanza}}
 {%- endfor -%}
diff --git a/tests/unit/files/content_cache_rendered_haproxy_test_output.txt b/tests/unit/files/content_cache_rendered_haproxy_test_output.txt
index 8a22a4b..f2077ab 100644
--- a/tests/unit/files/content_cache_rendered_haproxy_test_output.txt
+++ b/tests/unit/files/content_cache_rendered_haproxy_test_output.txt
@@ -39,6 +39,18 @@ defaults
 	errorfile 503 /etc/haproxy/errors/503.http
 	errorfile 504 /etc/haproxy/errors/504.http
 
+listen  stats
+	bind 127.0.0.1:10000
+	acl allowed_cidr src 127.0.0.0/8
+	http-request deny unless allowed_cidr
+
+	mode http
+	stats enable
+	stats uri /
+	stats realm Haproxy\ Statistics
+	stats auth haproxy:biometricsarenotsecret
+	stats refresh 3
+
 
 listen combined-80
     bind 0.0.0.0:80
diff --git a/tests/unit/files/haproxy_config_rendered_test_output.txt b/tests/unit/files/haproxy_config_rendered_test_output.txt
index ad46463..5e27f5b 100644
--- a/tests/unit/files/haproxy_config_rendered_test_output.txt
+++ b/tests/unit/files/haproxy_config_rendered_test_output.txt
@@ -39,6 +39,18 @@ defaults
 	errorfile 503 /etc/haproxy/errors/503.http
 	errorfile 504 /etc/haproxy/errors/504.http
 
+listen  stats
+	bind 127.0.0.1:10000
+	acl allowed_cidr src 127.0.0.0/8
+	http-request deny unless allowed_cidr
+
+	mode http
+	stats enable
+	stats uri /
+	stats realm Haproxy\ Statistics
+	stats auth haproxy:biometricsarenotsecret
+	stats refresh 3
+
 
 listen combined-80
     bind 0.0.0.0:80
diff --git a/tests/unit/test_content_cache.py b/tests/unit/test_content_cache.py
index 5228d45..e1390c0 100644
--- a/tests/unit/test_content_cache.py
+++ b/tests/unit/test_content_cache.py
@@ -221,7 +221,8 @@ site1.local:
 
         with mock.patch('lib.haproxy.HAProxyConf.conf_file', new_callable=mock.PropertyMock) as mock_conf_file:
             mock_conf_file.return_value = os.path.join(self.tmpdir, 'haproxy.cfg')
-            content_cache.configure_haproxy()
+            with mock.patch('charmhelpers.core.host.pwgen', return_value="biometricsarenotsecret"):
+              content_cache.configure_haproxy()
             self.assertFalse(service_start_or_restart.assert_called_with('haproxy'))
 
             # Again, this time should be no change so no need to restart HAProxy
diff --git a/tests/unit/test_haproxy.py b/tests/unit/test_haproxy.py
index 978a4bf..3d46385 100644
--- a/tests/unit/test_haproxy.py
+++ b/tests/unit/test_haproxy.py
@@ -67,7 +67,8 @@ class TestLibHAProxy(unittest.TestCase):
         haproxy = HAProxy.HAProxyConf(self.tmpdir)
         config = self.site_config
         num_procs = 4
-        self.assertTrue(haproxy.write(haproxy.render(config, num_procs)))
+        password = "biometricsarenotsecret"
+        self.assertTrue(haproxy.write(haproxy.render(config, num_procs, monitoring_password=password)))
         with open(haproxy.conf_file, 'r') as f:
             new_conf = f.read()
         with open('tests/unit/files/haproxy_config_rendered_test_output.txt', 'r') as f: