Add the ability to post to and act uponconfiguration in etcd

Etcd is a distributed, highly available name-value store that is
the basis of many clustered applications. However, it can also be
run on a standalone machine. Using etcd allows live monitoring
and possibly changing configuration while the sim is running.

OpenSim/Region/OptionalModules/Framework/Monitoring/EtcdMonitoringModule.cs

@@ -0,0 +1,195 @@
+/*
+ * Copyright (c) Contributors, http://opensimulator.org/
+ * See CONTRIBUTORS.TXT for a full list of copyright holders.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the OpenSimulator Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+using System;
+using System.Collections.Generic;
+using System.Reflection;
+using System.Text;
+using log4net;
+using Mono.Addins;
+using Nini.Config;
+using OpenMetaverse;
+using OpenSim.Framework;
+using OpenSim.Framework.Console;
+using OpenSim.Region.Framework.Interfaces;
+using OpenSim.Region.Framework.Scenes;
+using netcd;
+using netcd.Serialization;
+using netcd.Advanced;
+using netcd.Advanced.Requests;
+
+namespace OpenSim.Region.OptionalModules.Framework.Monitoring
+{
+    /// <summary>
+    /// Allows to store monitoring data in etcd, a high availability
+    /// name-value store.
+    /// </summary>
+    [Extension(Path = "/OpenSim/RegionModules", NodeName = "RegionModule", Id = "EtcdMonitoringModule")]
+    public class EtcdMonitoringModule : INonSharedRegionModule, IEtcdModule
+    {
+        private static readonly ILog m_log = LogManager.GetLogger(MethodBase.GetCurrentMethod().DeclaringType);
+
+        protected Scene m_scene;
+        protected IEtcdClient m_client;
+        protected bool m_enabled = false;
+        protected string m_etcdBasePath = String.Empty;
+        protected bool m_appendRegionID = true;
+
+        public string Name
+        {
+            get { return "EtcdMonitoringModule"; }
+        }
+
+        public Type ReplaceableInterface
+        {
+            get { return null; }
+        }
+
+        public void Initialise(IConfigSource source)
+        {
+            if (source.Configs["Etcd"] == null)
+                return;
+
+            IConfig etcdConfig = source.Configs["Etcd"];
+
+            string etcdUrls = etcdConfig.GetString("EtcdUrls", String.Empty);
+            if (etcdUrls == String.Empty)
+                return;
+
+            m_etcdBasePath = etcdConfig.GetString("BasePath", m_etcdBasePath);
+            m_appendRegionID = etcdConfig.GetBoolean("AppendRegionID", m_appendRegionID);
+
+            if (!m_etcdBasePath.EndsWith("/"))
+                m_etcdBasePath += "/";
+
+            try
+            {
+                string[] endpoints = etcdUrls.Split(new char[] {','});
+                List<Uri> uris = new List<Uri>();
+                foreach (string endpoint in endpoints)
+                    uris.Add(new Uri(endpoint.Trim()));
+
+                m_client = new EtcdClient(uris.ToArray(), new DefaultSerializer(), new DefaultSerializer());
+            }
+            catch (Exception e)
+            {
+                m_log.DebugFormat("[ETCD]: Error initializing connection: " + e.ToString());
+                return;
+            }
+
+            m_log.DebugFormat("[ETCD]: Etcd module configured");
+            m_enabled = true;
+        }
+
+        public void Close()
+        {
+            //m_client = null;
+            m_scene = null;
+        }
+
+        public void AddRegion(Scene scene)
+        {
+            m_scene = scene;
+
+            if (m_enabled)
+            {
+                if (m_appendRegionID)
+                    m_etcdBasePath += m_scene.RegionInfo.RegionID.ToString() + "/";
+
+                m_log.DebugFormat("[ETCD]: Using base path {0} for all keys", m_etcdBasePath);
+
+                try
+                {
+                    m_client.Advanced.CreateDirectory(new CreateDirectoryRequest() {Key = m_etcdBasePath});
+                }
+                catch (Exception e)
+                {
+                    m_log.ErrorFormat("Exception trying to create base path {0}: " + e.ToString(), m_etcdBasePath);
+                }
+
+                scene.RegisterModuleInterface<IEtcdModule>(this);
+            }
+        }
+
+        public void RemoveRegion(Scene scene)
+        {
+        }
+
+        public void RegionLoaded(Scene scene)
+        {
+        }
+
+        public bool Store(string k, string v)
+        {
+            return Store(k, v, 0);
+        }
+
+        public bool Store(string k, string v, int ttl)
+        {
+            Response resp = m_client.Advanced.SetKey(new SetKeyRequest() { Key = m_etcdBasePath + k, Value = v, TimeToLive = ttl });
+
+            if (resp == null)
+                return false;
+
+            if (resp.ErrorCode.HasValue)
+            {
+                m_log.DebugFormat("[ETCD]: Error {0} ({1}) storing {2} => {3}", resp.Cause, (int)resp.ErrorCode, m_etcdBasePath + k, v);
+
+                return false;
+            }
+
+            return true;
+        }
+
+        public string Get(string k)
+        {
+            Response resp = m_client.Advanced.GetKey(new GetKeyRequest() { Key = m_etcdBasePath + k });
+
+            if (resp == null)
+                return String.Empty;
+
+            if (resp.ErrorCode.HasValue)
+            {
+                m_log.DebugFormat("[ETCD]: Error {0} ({1}) getting {2}", resp.Cause, (int)resp.ErrorCode, m_etcdBasePath + k);
+
+                return String.Empty;
+            }
+
+            return resp.Node.Value;
+        }
+
+        public void Delete(string k)
+        {
+            m_client.Advanced.DeleteKey(new DeleteKeyRequest() { Key = m_etcdBasePath + k });
+        }
+
+        public void Watch(string k, Action<string> callback)
+        {
+            m_client.Advanced.WatchKey(new WatchKeyRequest() { Key = m_etcdBasePath + k, Callback = (x) => { callback(x.Node.Value); } });
+        }
+    }
+}