コード例 #1
0
        public void AssertThat_Errors_CauseTracesToBeLoggedAsWell()
        {
            IList <LogEntry> logList = new List <LogEntry>();
            var filter = new TriggerableLevelFilter(
                CommonLogSeverity.Information,
                CommonLogSeverity.Error,
                CommonLogSeverity.Trace
                );
            var outputStream = new ListOutputStream <LogEntry>(logList);

            using var logger = new FilteredLogger(
                      new OutputLogger(outputStream),
                      filter.Apply
                      );

            logger.LogTrace(new EventId(1, ""), new { });
            // assert nothing has been written
            Assert.Equal(0, logList.Count);

            logger.LogInformation(new EventId(2, ""), new { });
            // assert information has been written
            Assert.Equal(1, logList.Count);
            Assert.Equal(2, logList[0].EventId.Id);

            logger.LogError(new EventId(3, ""), new { });
            // assert information, trace and error have been written
            Assert.Equal(3, logList.Count);
            Assert.Equal(2, logList[0].EventId.Id);
            Assert.Equal(1, logList[1].EventId.Id);
            Assert.Equal(3, logList[2].EventId.Id);

            logger.LogTrace(new EventId(4, ""), new { });
            // assert information, trace, error an trace have been written
            Assert.Equal(4, logList.Count);
            Assert.Equal(2, logList[0].EventId.Id);
            Assert.Equal(1, logList[1].EventId.Id);
            Assert.Equal(3, logList[2].EventId.Id);
            Assert.Equal(4, logList[3].EventId.Id);
        }
コード例 #2
0
        public static IServiceProvider BuildServiceProvider() =>
        new ServiceCollection()
        // aliasing the ProxyCachingLoggerFactory as transient ILoggerFactory
        .AddTransient <ILoggerFactory>(provider =>
                                       provider.GetRequiredService <ProxyCachingLoggerFactory>())

        // wrapping the logger with a filter
        // it will filter with a minimum log level of "Information"
        // if there is a log with a minimum log level of "Error"
        // then all previous logs and following logs with a minimum level of "Trace" will also be logged
        // new filters (and therefore an empty log cache) will be made because the factory is transient
        .Decorate <ILoggerFactory>(factory =>
                                   LoggerFactory(() =>
        {
            var filter = new TriggerableLevelFilter(
                CommonLogSeverity.Information,
                CommonLogSeverity.Error,
                CommonLogSeverity.Trace);
            return(new FilteredLogger(factory.CreateLogger(), filter.Apply));
        })
                                   )
        // wrapping the logger with a try-catch
        // when an error is caused by a log, that error is logged instead
        .Decorate <ILoggerFactory>(factory =>
                                   LoggerFactory(() => new FailsafeLogger(factory.CreateLogger()))
                                   )

        // registering the loggers
        .AddSingleton(provider =>
                      // provide a proxy layer for loggers so that loggers that were created earlier,
                      //    will still use the appropriate logger for the current execution context
                      new ProxyCachingLoggerFactory(
                          LoggerFactory(() =>
        {
            // create a sequenceId, a unique identifier to correlate logs within the same execution
            var sequenceId = Guid.NewGuid();
            return(new ScopedSequenceLogger(
                       // create a source to identify where logs came from once they are collected in a central database
                       new ScopedSourceLogger(
                           // change type of pipeline
                           new OutputLogger(
                               // format structured logs as json
                               JsonLogOutput.CreateLogOutputStream(
                                   // write json logs to the console
                                   new ConsoleOutputStream()
                                   )
                               ),
                           source => source.Plus("SystemServiceProvider-Example")
                           ),
                       guid => sequenceId
                       ));
        })
                          )
                      )

        // allowing services to ask for an ILogger
        .AddScoped(provider =>
                   provider.GetRequiredService <ILoggerFactory>()
                   .CreateLogger())

        // providing other services
        .AddTransient <ExampleProgram>()
        .AddTransient <ExampleTransientService>()
        .AddTransient <ExampleSingletonService>()
        .BuildServiceProvider();