Hangfire 重复作业不工作 - 抛出异常："Unable to find a constructor"

Question

我有 .net 核心 2.1 网络应用程序和 Hangfire 库 (1.7.9) 在 postgres (12) 上工作。

我尝试添加循环作业，但每次 Hangfire 尝试启动它时，它都会抛出异常：

"Hangfire.Common.JobLoadException: Could not load the job. See inner exception for the details. ---> Newtonsoft.Json.JsonSerializationException: Unable to find a constructor to use for type Microsoft.Extensions.FileProviders.PhysicalFileProvider. A class should either have a default constructor, one constructor with arguments or a constructor marked with the JsonConstructor attribute. Path 'Providers[0].Source.FileProvider.Root', line 1, position 490."

我的启动文件（Hangfire 部分）：

 private void ConfigureHangfire(IServiceCollection services)
        {
            var settings = Configuration.GetSettings<HangfireSettings>();

            GlobalConfiguration.Configuration
                .SetDataCompatibilityLevel(CompatibilityLevel.Version_170)
                .UseSimpleAssemblyNameTypeSerializer()
                .UseRecommendedSerializerSettings()
                .UsePostgreSqlStorage(Configuration.GetConnectionString("service_user"), new PostgreSqlStorageOptions
                {
                    SchemaName = "hangfire",
                    QueuePollInterval = TimeSpan.FromSeconds(15),
                    UseNativeDatabaseTransactions = true,
                    PrepareSchemaIfNecessary = true,
                    TransactionSynchronisationTimeout = TimeSpan.FromMinutes(15)
                });

            var options = new PostgreSqlStorageOptions
            {
                PrepareSchemaIfNecessary = settings.CreateDatabaseAutomatically
            };

            services.AddHangfire(config => config.UsePostgreSqlStorage(Configuration.GetConnectionString("service_user"), options));

            DailyDatabaseUpdate.TurnOnDailyUpdateScheduleWorker(9, 51, Configuration);
        }

测试后我意识到我的方法 DailyDatabaseUpdate.TurnOnDailyUpdateScheduleWorker(9, 51, Configuration); 包含参数 IConfiguration 配置 .当我删除它时，一切正常。但是这个接口对于获取我的连接字符串至关重要。

如何解决？

Answer 1

一个好的解决方案是将连接字符串设置为 IOption 或类似的东西，例如将配置绑定到某个对象，然后构造函数将此对象注入到 class 中，其中包含充当重复作业的方法。

示例：

public StatusJobs(DbOptions dbOptions)
{
    _dbOptions= dbOptions
}

[DisableConcurrentExecution(timeoutInSeconds: 20)]
[AutomaticRetry(Attempts = 0, OnAttemptsExceeded = AttemptsExceededAction.Delete)]
public void DoSmth()
{
    //dbOptions avalaible here
}

此外，最好注入一些 connectionfactory 而不是 connectiostring。

Hangfire 重复作业不工作 - 抛出异常："Unable to find a constructor"

Hangfire Recurring jobs not working - throw exception: "Unable to find a constructor"

postgresql

hangfire

.net-core