I'm using a Node.JS backend on Azure with Easy Tables. The table contains the required columns to support offline syncing.
While testing the sync process I noticed that conflicts keep coming back even though I'm resolving them.
My test:
Pull table content from Azure to iOS and Android device
Change a record on iOS but don't sync back to Azure
Change the same record on Android and sync
Now sync iOS
As expected, the conflict is detected correctly and I catch a MobileServicePushFailedException. I am then resolving the error by replacing the local item with the server item:
localItem.AzureVersion = serverItem.AzureVersion;
await result.UpdateOperationAsync(JObject.FromObject (localItem));
However, the next time I sync, the same item fails again with the same error.
The AzureVersion property is declared like this:
[Version]
public string AzureVersion { get; set; }
What exactly is result.UpdateOperationAsync() doing? Does it update my local database? Do I have to do it manually?
And also: am I supposed to trigger an explicit PushAsync() afterwards?
EDIT:
I changed the property from AzureVersion to Version and it works. I noticed that the serverItem's AzureVersion property was NULL even though the JSON contained it. Bug in Json.Net or in the Azure Mobile Client?
You should be using something like the following:
public async Task SyncAsync()
{
ReadOnlyCollection<MobileServiceTableOperationError> syncErrors = null;
try
{
await this.client.SyncContext.PushAsync();
await this.todoTable.PullAsync(
//The first parameter is a query name that is used internally by the client SDK to implement incremental sync.
//Use a different query name for each unique query in your program
"allTodoItems",
this.todoTable.CreateQuery());
}
catch (MobileServicePushFailedException exc)
{
if (exc.PushResult != null)
{
syncErrors = exc.PushResult.Errors;
}
}
// Simple error/conflict handling. A real application would handle the various errors like network conditions,
// server conflicts and others via the IMobileServiceSyncHandler.
if (syncErrors != null)
{
foreach (var error in syncErrors)
{
if (error.OperationKind == MobileServiceTableOperationKind.Update && error.Result != null)
{
//Update failed, reverting to server's copy.
await error.CancelAndUpdateItemAsync(error.Result);
}
else
{
// Discard local change.
await error.CancelAndDiscardItemAsync();
}
Debug.WriteLine(#"Error executing sync operation. Item: {0} ({1}). Operation discarded.", error.TableName, error.Item["id"]);
}
}
}
Note the CancelAndUpdateItemAsync(), which updates the item to the server copy or CancelAndDiscardItemAsync(), which accepts the local item. These are the important things for you.
This code came from the official HOWTO docs here: https://azure.microsoft.com/en-us/documentation/articles/app-service-mobile-dotnet-how-to-use-client-library/##offlinesync
Related
I'm looking to have our distributed event logging have proper correlation. For our Web Applications this seems to be automatic. Example of correlated logs from one of our App Services API:
However, for our other (non ASP, non WebApp) services were we use Log4Net and the App Insights appender our logs are not correlated. I tried following instructions here: https://learn.microsoft.com/en-us/azure/azure-monitor/app/correlation
Even after adding unique operation_Id attributes to each operation, we're not seeing log correlation (I also tried "Operation Id"). Example of none correlated log entry:
Any help on how to achieve this using log4net would be appreciated.
Cheers!
Across services correlation IDs are mostly propagated through headers. When AI is enabled for Web Application, it reads IDs/Context from the incoming headers and then updates outgoing headers with the appropriate IDs/Context. Within service, operation is tracked with Activity object and every telemetry emitted will be associated with this Activity, thus sharing necessary correlation IDs.
In case of Service Bus / Event Hub communication, the propagation is also supported in the recent versions (IDs/Context propagate as metadata).
If service is not web-based and AI automated correlation propagation is not working, you may need to manually get incoming ID information from some metadata if any exists, restore/initiate Activity, start AI operation with this Activity. When telemetry item is generated in scope of that Activity, it will get proper IDs and will be part of the overarching trace. With that, if telemetry is generated from Log4net trace that was executed in the scope of AI operation context then that telemetry should get right IDs.
Code sample to access correlation from headers:
public class ApplicationInsightsMiddleware : OwinMiddleware
{
// you may create a new TelemetryConfiguration instance, reuse one you already have
// or fetch the instance created by Application Insights SDK.
private readonly TelemetryConfiguration telemetryConfiguration = TelemetryConfiguration.CreateDefault();
private readonly TelemetryClient telemetryClient = new TelemetryClient(telemetryConfiguration);
public ApplicationInsightsMiddleware(OwinMiddleware next) : base(next) {}
public override async Task Invoke(IOwinContext context)
{
// Let's create and start RequestTelemetry.
var requestTelemetry = new RequestTelemetry
{
Name = $"{context.Request.Method} {context.Request.Uri.GetLeftPart(UriPartial.Path)}"
};
// If there is a Request-Id received from the upstream service, set the telemetry context accordingly.
if (context.Request.Headers.ContainsKey("Request-Id"))
{
var requestId = context.Request.Headers.Get("Request-Id");
// Get the operation ID from the Request-Id (if you follow the HTTP Protocol for Correlation).
requestTelemetry.Context.Operation.Id = GetOperationId(requestId);
requestTelemetry.Context.Operation.ParentId = requestId;
}
// StartOperation is a helper method that allows correlation of
// current operations with nested operations/telemetry
// and initializes start time and duration on telemetry items.
var operation = telemetryClient.StartOperation(requestTelemetry);
// Process the request.
try
{
await Next.Invoke(context);
}
catch (Exception e)
{
requestTelemetry.Success = false;
telemetryClient.TrackException(e);
throw;
}
finally
{
// Update status code and success as appropriate.
if (context.Response != null)
{
requestTelemetry.ResponseCode = context.Response.StatusCode.ToString();
requestTelemetry.Success = context.Response.StatusCode >= 200 && context.Response.StatusCode <= 299;
}
else
{
requestTelemetry.Success = false;
}
// Now it's time to stop the operation (and track telemetry).
telemetryClient.StopOperation(operation);
}
}
public static string GetOperationId(string id)
{
// Returns the root ID from the '|' to the first '.' if any.
int rootEnd = id.IndexOf('.');
if (rootEnd < 0)
rootEnd = id.Length;
int rootStart = id[0] == '|' ? 1 : 0;
return id.Substring(rootStart, rootEnd - rootStart);
}
}
Code sample for manual correlated operation tracking in isolation:
async Task BackgroundTask()
{
var operation = telemetryClient.StartOperation<DependencyTelemetry>(taskName);
operation.Telemetry.Type = "Background";
try
{
int progress = 0;
while (progress < 100)
{
// Process the task.
telemetryClient.TrackTrace($"done {progress++}%");
}
// Update status code and success as appropriate.
}
catch (Exception e)
{
telemetryClient.TrackException(e);
// Update status code and success as appropriate.
throw;
}
finally
{
telemetryClient.StopOperation(operation);
}
}
Please note that the most recent version of Application Insights SDK is switching to W3C correlation standard, so header names and expected format would be different as per W3C specification.
Whatever I tried I cannot set an extension property on a User object, here is a reproducible piece of code:
public async Task CleanTest(string extName)
{
ExtensionProperty ep = new ExtensionProperty
{
Name = extName,
DataType = "String",
TargetObjects = { "User" }
};
App app = (App)(await _client.Applications.Where(a => a.AppId == _managementAppClientId).ExecuteSingleAsync());
app.ExtensionProperties.Add(ep);
await app.UpdateAsync();
GraphUser user = (GraphUser)(await _client.Users.Where(u => u.UserPrincipalName.Equals("email")).ExecuteSingleAsync());
string propName = FormatExtensionPropertyName(extName); //formats properly as extesion_xxx_name
user.SetExtendedProperty(propName, "testvalue");
//user.SetExtendedProperty(extName, "testvalue");
await user.UpdateAsync(); // fails here
}
user.UpdateAsync() according to Fiddler doesn't even go out and application fails with an exception:
"The property 'extension_e206e28ff36244b19bc56c01160b9cf0_UserEEEqdbtgd3ixx2' does not exist on type 'Microsoft.Azure.ActiveDirectory.GraphClient.Internal.User'. Make sure to only use property names that are defined by the type."
This issue is also being tracked here:
https://github.com/Azure-Samples/active-directory-dotnet-graphapi-console/issues/28
I've got an alternative workaround for this bug, for those that want to use the version 5.7 OData libraries rather than redirecting to the v5.6.4 versions.
Add a request pipeline configuration handler.
// initialize in the usual way
ActiveDirectoryClient activeDirectoryClient =
AuthenticationHelper.GetActiveDirectoryClientAsApplication();
// after initialization add a handler to the request pipline configuration.
activeDirectoryClient.Context
.Configurations.RequestPipeline
.OnMessageWriterSettingsCreated(UndeclaredPropertyHandler);
In the handler, change the ODataUndeclaredPropertyBehaviorKinds value on the writer settings to SupportUndeclaredValueProperty.
private static void UndeclaredPropertyHandler(MessageWriterSettingsArgs args)
{
var field = args.Settings.GetType().GetField("settings",
BindingFlags.NonPublic | BindingFlags.Instance);
var settingsObject = field?.GetValue(args.Settings);
var settings = settingsObject as ODataMessageWriterSettings;
if (settings != null)
{
settings.UndeclaredPropertyBehaviorKinds =
ODataUndeclaredPropertyBehaviorKinds.SupportUndeclaredValueProperty;
}
}
Just in case you still looking for solution to this problem or someone else is facing the same issue:
I got similar issue and it looks like, at least for me, the problem was in latest version of "Microsoft.Data.Services.Client" package - 5.7.0 (or in one of it dependencies). When I downgraded to previous version - 5.6.4 it worked as a charm.
I had same symptoms - updating of extended property was failing even w/o any request is made (also used Fiddler)
Hope it helps!
Artem Liman
I assumed that we should use basicredisclientmanager or pooledredisclientmanager?
I tried this
private void dddddd()
{
for(int i=0;i<=1000;i++)
{
var client = new BasicRedisClientManager(new string[] { "host1", "host2", "host3" }).GetClient();
//do something with client
}
}
This loop runs fine for the first 100 plus but after that, I always got an error "Unknown Command Role"?? What is that and how to fix it? I need help!
I also tried to make a new class called MyRedisMgr and created a static property to create some sort of singleton but it didn't work either.
public BasicRedisClientManager MyMgr = new BasicRedisClientManager(new string[] { "host1", "host2", "host3" });
And then I use it like
for(int i=0;i<=1000;i++)
{
var client = MyRedisMgr.MyMgr.GetClient();
//do something with client
}
Please read the documentation on the proper usage of Redis Client Manager which should only be used as a singleton.
The BasicRedisClientManager doesn't have any connection pooling so every time you call GetClient() you're opening a new TCP connection with the redis-server. Unless you understand the implications you should be using one of the Pooled Redis Client Managers, e.g: RedisManagerPool.
You also need to always dispose the client after its used so that it can either be re-used or the TCP connection disposed of properly.
So your code sample should look like:
//Always use the same singleton instance of a Client Manager
var redisManager = new RedisManagerPool(masterHost);
for(int i=0;i<=1000;i++)
{
using (var redis = redisManager.GetClient())
{
//do something with client
}
}
The "Unknown Command Role" error is due to using an old version of Redis Server. The ROLE command was added in redis 2.8.12 but this API should only be used if your using redis-server v2.8.12+, so you shouldn't be getting this error by default. You can avoid this error by upgrading to either the stable v3.0 or old 2.8 versions of redis-server which has this command.
If you want to continue using an older version, use the INFO command to check what version you're running then tell ServiceStack.Redis what the version is with:
RedisConfig.AssumeServerVersion = 2600; //e.g. v2.6
RedisConfig.AssumeServerVersion = 2612; //e.g. v2.6.12
In trying to integrate RavenDB usage with Service Stack, I ran across the following solution proposed for session management:
A: using RavenDB with ServiceStack
The proposal to use the line below to dispose of the DocumentSession object once the request is complete was an attractive one.
container.Register(c => c.Resolve<IDocumentStore>().OpenSession()).ReusedWithin(ReuseScope.Request);
From what I understand of the Funq logic, I'm registering a new DocumentSession object with the IoC container that will be resolved for IDocumentSession and will only exist for the duration of the request. That seemed like a very clean approach.
However, I have since run into the following max session requests exception from RavenDB:
The maximum number of requests (30) allowed for this session has been
reached. Raven limits the number of remote calls that a session is
allowed to make as an early warning system. Sessions are expected to
be short lived, and Raven provides facilities like Load(string[] keys)
to load multiple documents at once and batch saves.
Now, unless I'm missing something, I shouldn't be hitting a request cap on a single session if each session only exists for the duration of a single request. To get around this problem, I tried the following, quite ill-advised solution to no avail:
var session = container.Resolve<IDocumentStore>().OpenSession();
session.Advanced.MaxNumberOfRequestsPerSession = 50000;
container.Register(p => session).ReusedWithin(ReuseScope.Request);
Here is a sample of how I'm using the resolved DocumentSession instance:
private readonly IDocumentSession _session;
public UsersService(IDocumentSession session)
{
_session = session;
}
public ServiceResponse<UserProfile> Get(GetUser request)
{
var response = new ServiceResponse<UserProfile> {Successful = true};
try
{
var user = _session.Load<UserProfile>(request.UserId);
if (user == null || user.Deleted || !user.IsActive || !user.IsActive)
{
throw HttpError.NotFound("User {0} was not found.".Fmt(request.UserId));
}
response.Data = user;
}
catch (Exception ex)
{
_logger.Error(ex.Message, ex);
response.StackTrace = ex.StackTrace;
response.Errors.Add(ex.Message);
response.Successful = false;
}
return response;
}
As far as I can see, I'm implementing SS + RavenDB "by the book" as far as the integration point goes, but I'm still getting this max session request exception and I don't understand how. I also cannot reliably replicate the exception or the conditions under which it is being thrown, which is very unsettling.
I'd like to override delete operation on my Azure Mobile Services table to make it more like update then real delete. I have additional column named IsDeleted and I'd like to set it's value to true when delete operation is executed.
I figured out, that what I need is:
fire my own 'update' inside del function,
delete current request.execute()
prepare and sent response by myself
That meens my del function should look like that:
function del(id, user, request) {
// execute update query to set 'isDeleted' - true
// return standard response
request.respond();
}
As you can see I'm missing the first part of the function - the update one. Could you help me writing it? I read Mobile Services server script reference but there is no info about making additional queries inside a server script function.
There are basically two ways to do that - using the tables object, and using the mssql object. The links point to the appropriate reference.
Using mssql (I didn't try it, you may need to update your SQL statement):
function del(id, user, request) {
var sql = 'UPDATE <yourTableName> SET isDeleted = true WHERE id = ?';
mssql.query(sql, [id], {
success: function() {
request.respond(statusCodes.OK);
}
});
}
Using tables (again, only tested in notepad):
function del(id, user, request) {
var table = tables.getTable('YourTableName');
table.where({ id: id }).read({
success: function(items) {
if (items.length === 0) {
request.respond(statusCodes.NOT_FOUND);
} else {
var item = items[0];
item.isDeleted = true;
table.update(item, {
success: function() {
request.respond(statusCodes.OK, item);
}
});
}
}
});
}
There is a Node.js driver for SQL Server that you might want to check out.
The script component of Mobile Services uses node.js. You might want to check out the session from AzureConf called Javascript, meet cloud