UseTagsWithMongo error on startup

[gunsh]

I have an existing Hangfire app. The thing I am missing the most is some sort of search capability. Somebody suggested to try Hangfire.Tags and so I did. I followed the instructions but I got the error below upon startup. I am not doing anything fancy. I have just added a call to UseTagsWithMongo. I don't see anything special in the provided sample code either. Using Hangfire.AspNetCore 1.8.17 and Hangfire.Mongo 1.11.2.

                var mongoStorageOptions = new MongoStorageOptions
                {
                    SupportsCappedCollection = supportsCappedCollection,
                    MigrationOptions = new MongoMigrationOptions
                    {
                        MigrationStrategy = new DropMongoMigrationStrategy(),
                        BackupStrategy = new NoneMongoBackupStrategy(),
                    },
                    CheckQueuedJobsStrategy = uri.Scheme == "mongodb" && supportsCappedCollection
                        ? CheckQueuedJobsStrategy.TailNotificationsCollection
                        : CheckQueuedJobsStrategy.Watch,
                    Prefix = "hangfire",
                    CheckConnection = true
                };

                // ....

                    .UseMongoStorage(
                        connectionString,
                        mongoStorageOptions
                    )
                    .UseTagsWithMongo(new TagsOptions() { TagsListStyle = TagsListStyle.Dropdown }, mongoStorageOptions);

And here is the error:

InvalidOperationException: Sequence contains no elements
System.Linq.ThrowHelper.ThrowNoElementsException()
System.Linq.Enumerable.Single<TSource>(IEnumerable<TSource> source)
MongoDB.Driver.IAsyncCursorExtensions.Single<TDocument>(IAsyncCursor<TDocument> cursor, CancellationToken cancellationToken)
MongoDB.Driver.IAsyncCursorSourceExtensions.Single<TDocument>(IAsyncCursorSource<TDocument> source, CancellationToken cancellationToken)
MongoDB.Driver.IAggregateFluentExtensions.Single<TResult>(IAggregateFluent<TResult> aggregate, CancellationToken cancellationToken)
Hangfire.Tags.Mongo.MongoTagsServiceStorage.GetTagCount(JobStorage jobStorage, string setKey)
Hangfire.Tags.Storage.TagsStorage.GetTagsCount()
Hangfire.Tags.Dashboard.TagDashboardMetrics+<>c.<.cctor>b__1_0(RazorPage razorPage)
Hangfire.Dashboard.Pages.InlineMetric.Execute() in _InlineMetric.cshtml
Hangfire.Dashboard.RazorPage.TransformText(string body) in RazorPage.cs
Hangfire.Dashboard.RazorPage.ToString() in RazorPage.cs
Hangfire.Dashboard.HtmlHelper.RenderPartial(RazorPage partialPage) in HtmlHelper.cs
Hangfire.Dashboard.HtmlHelper.InlineMetric(DashboardMetric metric) in HtmlHelper.cs
Hangfire.Dashboard.Pages.SidebarMenu.Execute() in _SidebarMenu.cshtml
Hangfire.Dashboard.RazorPage.TransformText(string body) in RazorPage.cs
Hangfire.Dashboard.RazorPage.ToString() in RazorPage.cs
Hangfire.Dashboard.HtmlHelper.RenderPartial(RazorPage partialPage) in HtmlHelper.cs
Hangfire.Dashboard.HtmlHelper.JobsSidebar() in HtmlHelper.cs
Hangfire.Dashboard.Pages.QueuesPage.Execute() in QueuesPage.cshtml
Hangfire.Dashboard.RazorPage.TransformText(string body) in RazorPage.cs
Hangfire.Dashboard.RazorPage.ToString() in RazorPage.cs
Hangfire.Dashboard.RazorPageDispatcher.Dispatch(DashboardContext context) in RazorPageDispatcher.cs
Hangfire.Dashboard.AspNetCoreDashboardMiddleware.Invoke(HttpContext httpContext) in AspNetCoreDashboardMiddleware.cs
Microsoft.AspNetCore.Builder.Extensions.MapMiddleware.InvokeCore(HttpContext context, PathString matchedPath, PathString remainingPath)
Microsoft.AspNetCore.Authorization.AuthorizationMiddleware.Invoke(HttpContext context)
Microsoft.AspNetCore.Authentication.AuthenticationMiddleware.Invoke(HttpContext context)
Swashbuckle.AspNetCore.SwaggerUI.SwaggerUIMiddleware.Invoke(HttpContext httpContext)
Swashbuckle.AspNetCore.Swagger.SwaggerMiddleware.Invoke(HttpContext httpContext, ISwaggerProvider swaggerProvider)

[erwin-faceit]

The sample dashboard first launches a few tasks, but when I remove these, and start with an empty Mongo database, I get the exact same result. So I'm guessing that your database also doesn't have any tags yet.

I've just made a change to the code, give it some time, and NuGet will show version 1.9.1 which should fix this issue.

[gunsh]

Yes, you are right. My db had no tags but I expect this to be the default for anyone adopting your library. Anyway, your fix did work and now I see "Tags" in the Hangfire left-hand menu. Thanks for fixing this.

Still, when I navigate to "Tags", I get a MongoDB load error:

      System.IO.FileNotFoundException: Could not load file or assembly 'MongoDB.Driver.Core, Version=2.19.2.0, Culture=neutral, PublicKeyToken=null'. The system cannot find the file specified.
      File name: 'MongoDB.Driver.Core, Version=2.19.2.0, Culture=neutral, PublicKeyToken=null'
         at Hangfire.Tags.Mongo.MongoTagsServiceStorage.SearchWeightedTags(JobStorage jobStorage, String tag, String setKey)
         at Hangfire.Tags.Storage.TagsStorage.SearchWeightedTags(String tag)
         at Hangfire.Tags.Dashboard.Pages.TagsSearchPage.Execute()
         at Hangfire.Dashboard.RazorPage.TransformText(String body) in C:\projects\hangfire-525\src\Hangfire.Core\Dashboard\RazorPage.cs:line 179
         at Hangfire.Dashboard.RazorPage.ToString() in C:\projects\hangfire-525\src\Hangfire.Core\Dashboard\RazorPage.cs:line 103
         at Hangfire.Dashboard.RazorPageDispatcher.Dispatch(DashboardContext context) in C:\projects\hangfire-525\src\Hangfire.Core\Dashboard\RazorPageDispatcher.cs:line 38
         at Hangfire.Dashboard.AspNetCoreDashboardMiddleware.Invoke(HttpContext httpContext) in C:\projects\hangfire-525\src\Hangfire.AspNetCore\Dashboard\AspNetCoreDashboardMiddleware.cs:line 99
         at Microsoft.AspNetCore.Builder.Extensions.MapMiddleware.InvokeCore(HttpContext context, PathString matchedPath, PathString remainingPath)
         at Microsoft.AspNetCore.Authorization.AuthorizationMiddleware.Invoke(HttpContext context)
         at Microsoft.AspNetCore.Authentication.AuthenticationMiddleware.Invoke(HttpContext context)

I am on the latest MongoDB 3.1.0 and your library seems to use 2.19.2. The two don't seem to be compatible. I have tried upgrading your sample to use MongoDB 3.1.0 just to see what happens but I get build errors.

Any ideas?