static IEtcdWatchStatus MonitorEtcd(IEtcdWatchStatus status)
{
IEtcdClient client = new EtcdClient();
status = client.Watch(status, null, (a, b) =>
{
Console.WriteLine("{0}-{1}", b.Node.Key, b.Node.Value);
return true;
},
(a,b) =>
{
if (b.PrevErrorsCount%5 == 0){
Console.WriteLine("Another 5 errors:" + b.Exception.Message);
}
if (a.AllFailed && a.Clients.Select(c => c.LastError.PrevErrorsCount).All(num => num > 15))
{
Console.WriteLine("Fatal Error in etcd cluster, Reinitializing...");
a.AbortAll(); //implicit not running
MonitorEtcd(status);
}
return true;
},true);
return status;
}
/// <summary>
/// Sets up a watch on a keyspace and will call the callback when triggered
/// </summary>
/// <param name="externalStatus">previous status to update</param>
/// <param name="key">key</param>
/// <param name="followUp">callback</param>
/// <param name="onError">optional error handler</param>
/// <param name="recursive">watch subkeys?</param>
/// <param name="timeout">How long will we watch?</param>
/// <param name="waitIndex">Index to wait from</param>
public IEtcdWatchStatus Watch(IEtcdWatchStatus externalStatus, string key, Func<IEtcdWatchStatus, EtcdResponse, bool> followUp, Func<IEtcdWatchStatus, EtcdErrorResult, bool> onError = null, bool recursive = false, int? timeout = null, int? waitIndex = null)
{
if (followUp == null)
throw new ArgumentNullException("followUp");
//if (key == null)
// throw new ArgumentNullException("key");
if(externalStatus == null )
externalStatus = new EtcdWatchStatus();
else if(!(externalStatus is EtcdWatchStatus))
throw new ArgumentException("you cant implement externalStatus yourself, but should obtain it from previous call to Watch");
EtcdWatchStatus status = (EtcdWatchStatus)externalStatus;
status.Cleanup();
//handle for forced close, if such
//default error handler
if (onError == null)
{
onError = (a,b) =>
{
//rest a while
Thread.Sleep(50);
return true;
};
}
Action<IRestResponse<EtcdResponse>, RestRequestAsyncHandle> callback = null;
callback = (b,c) =>
{
if (!status.Running)
return;
var baseUrl = getResponseBaseUri(b.Request, c);
//some weird fix for rest response
if (String.IsNullOrWhiteSpace(b.Server))
b.Server = baseUrl.ToString();
var clientContext = status.Clients.First(a => a.Server == baseUrl);
if (checkForError(b))
{
clientContext.State = ClientState.Failed;
if(clientContext.LastError==null)
clientContext.LastError = new EtcdErrorResult();
//check for client shutdown or general watch abort
if (status.LockedCheck(()=>onError(status,clientContext.LastError.Update(constructException(b)))) && status.Running)
{
//we are still alive, try reconnect
clientContext.CurrentRequest = _clients
.First(a => a.BaseUrl == baseUrl)
.GetAsync<EtcdResponse>(prepareWaitOnKeyRequest(baseUrl, key, recursive, timeout, waitIndex), (r, h) => callback(r, h));
}
else
{
clientContext.State = ClientState.Down;
}
return;
}
clientContext.State = ClientState.Succeeded;
//avoid duplicated results from cluster and try to stop gracefully, if required
if (!status.Running) //check we are already aborted
return;
lock (status)
{
if (!status.Running)
return;
if (!status.LastResults.ContainsKey(b.Data.Node.Key) || status.LastResults[b.Data.Node.Key] != b.Data.Node.ModifiedIndex)
{
status.LastResults[b.Data.Node.Key] = b.Data.Node.ModifiedIndex;
if (!followUp(status, processRestResponse(b)))
{
status.Running = false;
status.AbortAll();
return;
}
}
}
//now wait for changes...
//see SetWaitable call
clientContext.CurrentRequest = _clients.First(a => a.BaseUrl == clientContext.Server)
.GetAsync<EtcdResponse>(b.Request.SetWaitable(), (r, h) => callback(r, h));
};
//all first requests are should return current value immediately
_clients.ForEach(a =>
{
ClientWatchContext context;
status.Clients.Add(context = new ClientWatchContext(a.BaseUrl) {State = ClientState.InProgress});
context.CurrentRequest = a.GetAsync<EtcdResponse>(
prepareWaitOnKeyRequest(a.BaseUrl,key, recursive, timeout, waitIndex).SetWaitable(),(r, h) => callback(r, h));
});
return status;
}
