The 'Job' field has a null or empty value in Hangfire

Question

In Startup.cs I tried to enqueue recurring job like this:

RecurringJob.AddOrUpdate(() => Console.WriteLine("test"), Cron.Daily);

but received the error:

Please help to figure out what I'm doing wrong.

My configuration:

    //HangFire
    services.AddHangfire(configuration => configuration
      .SetDataCompatibilityLevel(CompatibilityLevel.Version_170)
      .UseSimpleAssemblyNameTypeSerializer()
      .UseRecommendedSerializerSettings()
      .UseSqlServerStorage(Configuration.GetConnectionString("HangfireConnection"),
          new SqlServerStorageOptions
          {
              CommandBatchMaxTimeout = TimeSpan.FromMinutes(5),
              SlidingInvisibilityTimeout = TimeSpan.FromMinutes(5),
              QueuePollInterval = TimeSpan.Zero,
              UseRecommendedIsolationLevel = true,
              DisableGlobalLocks = true,
          }
      ));

P.S. although 'fire and forget' jobs works.

Here is a [link](https://github.com/HangfireIO/Hangfire/issues/1576) that says it should be ignored — Jawad, May 18 '21 at 16:27

Timothy G. · Accepted Answer · 2022-09-14T12:43:11.820

Hangfire's source indicates that this exception (and message) is thrown when the expression !recurringJob.ContainsKey("Job") || String.IsNullOrWhiteSpace(recurringJob["Job"]) is true.

try
{
    if (!recurringJob.ContainsKey("Job") || String.IsNullOrWhiteSpace(recurringJob["Job"]))
    {
        throw new InvalidOperationException("The 'Job' field has a null or empty value");
    }

    Job = InvocationData.DeserializePayload(recurringJob["Job"]).DeserializeJob();
}
catch (Exception ex)
{
    _errors.Add(ex);
}

The recurringJob Dictionary gets set by the method GetAllEntriesFromHash:

public override Dictionary<string, string> GetAllEntriesFromHash(string key)
{
    if (key == null) throw new ArgumentNullException(nameof(key));

    return _storage.UseConnection(_dedicatedConnection, connection =>
    {
        var result = connection.Query<SqlHash>(
            $"select Field, Value from [{_storage.SchemaName}].Hash with (forceseek, readcommittedlock) where [Key] = @key",
            new { key },
            commandTimeout: _storage.CommandTimeout)
            .ToDictionary(x => x.Field, x => x.Value);

        return result.Count != 0 ? result : null;
    });
}

So what is probably happening is the GetAllEntriesFromHash method is returning null, or a Dictionary that doesn't contain the key Job (or it's null/whitespace). But, in a thread, a Hangfire Contributor commented:

That's not even a problem, just ignore those exceptions or tell Visual Studio to not to break on them. Hangfire handles a lot of exceptions, and may generate tons of OperationCanceledException during shutdown that tells all the background processes that shutdown was requested.

Thus, it seems like this error can be ignored.

The 'Job' field has a null or empty value in Hangfire

1 Answers1