Merge ~hloeung/charm-graylog:master into ~graylog-charmers/charm-graylog:master

[Haw Loeung]

Add support for Graylog 2.3

Graylog 2.3 changes how it talks to ElasticSearch. Previously, the
binary protocol was used so Graylog would appear in the cluster just
like another Elasticsearch node. It's now changed to using the HTTP
REST API, and with that, the configuration option changed from
elasticsearch_discovery_zen_ping_unicast_hosts to
elasticsearch_hosts. See upgrade docs[1] for details.

[1]http://docs.graylog.org/en/2.3/pages/upgrade/graylog-2.3.html#upgrade-from-22-to-23

[Barry Price (barryprice)]

LGTM +1

review: Approve

diff --git a/lib/graylogapi.py b/lib/graylogapi.py
index 61393b2..e7a7ef3 100644
--- a/lib/graylogapi.py
+++ b/lib/graylogapi.py
@@ -80,7 +80,7 @@ class GraylogAPI:
         if index_id:
             return self._request('{}/{}'.format(url, index_id))
         else:
-            return self._request(url)['index_sets']
+            return self._request(url)['index_sets'] or None
 
     def index_set_update(self, index_id, data):
         if not self.token:
@@ -95,7 +95,7 @@ class GraylogAPI:
         if input_id:
             return self._request('{}/{}'.format(url, input_id))
         else:
-            return self._request(url)['inputs']
+            return self._request(url)['inputs'] or None
 
     def log_input_update(self, input_id=None, data=None):
         if not self.token:
diff --git a/reactive/graylog.py b/reactive/graylog.py
index 052ecd3..49902a1 100644
--- a/reactive/graylog.py
+++ b/reactive/graylog.py
@@ -97,7 +97,10 @@ def configure_index_sets(*discard):
                    username='admin',
                    password=db.get('admin_password'),
                    token_name='graylog-charm')
-    for iset in g.index_set_get():
+    index_sets = g.index_set_get()
+    if not index_sets:
+        return
+    for iset in index_sets:
         log = ''
         if iset['shards'] != conf['index_shards']:
             log += ' shards from {} to {}'.format(iset['shards'], conf['index_shards'])
@@ -205,6 +208,8 @@ def configure_inputs(*discard):
                    password=db.get('admin_password'),
                    token_name='graylog-charm')
     inputs = g.log_input_get()
+    if not inputs:
+        return
     new_opened_ports = []
     new_inputs = []
     for new in yaml.safe_load(conf['log_inputs']) or {}:
@@ -258,24 +263,27 @@ def configure_inputs(*discard):
 @when('elasticsearch.available')
 def configure_elasticsearch_connection(elasticsearch):
     cluster = ""
-    hosts = []
+    # Pre-2.3.x discovery unicast hosts (binary ElasticSearch protocol)
+    discovery_hosts = []
+    # 2.3.x and above HTTP REST API
+    http_hosts = []
     for unit in elasticsearch.list_unit_data():
         cluster_name = unit['cluster_name']
         if cluster_name is not None:
             cluster = cluster_name
-        # The relation is reporting the http port not the zen discovery port
-        # hosts.append('{}:{}'.format(unit['host'], unit['port']))
-        hosts.append('{}:{}'.format(unit['host'], ELASTICSEARCH_DISCOVERY_PORT))
+        http_hosts.append('http://{}:{}'.format(unit['host'], unit['port']))
+        discovery_hosts.append('{}:{}'.format(unit['host'], ELASTICSEARCH_DISCOVERY_PORT))
 
     if not cluster:
         conf = hookenv.config()
         cluster = conf['elasticsearch_cluster_name']
 
-    if not data_changed('elasticsearch.relation', {'cluster_name': cluster, 'hosts': hosts}):
+    if not data_changed('elasticsearch.relation', {'cluster_name': cluster, 'hosts': http_hosts}):
         return
 
     set_conf('elasticsearch_cluster_name', cluster)
-    set_conf('elasticsearch_discovery_zen_ping_unicast_hosts ', ', '.join(hosts))
+    set_conf('elasticsearch_discovery_zen_ping_unicast_hosts ', ', '.join(discovery_hosts))
+    set_conf('elasticsearch_hosts', ', '.join(http_hosts))
     # Elastic search does not reliably pick the right ip to listen on
     set_conf('elasticsearch_network_host', hookenv.unit_private_ip())