Logging in multiple files with filters which are ignored

Question

I have defined two Filters for a serilog LoggerConfiguration Both are RollingFile loggers which should, depending on the type write in a log file in another folder.

var activityPath = @"C:\temp\Activities\log-{Date}.log";

var eventsPath = @"C:\temp\Events\log-{Date}.log";

loggerConfig.WriteTo.Logger(
                    lc =>
                        lc.Filter.ByExcluding(Matching.FromSource<EventLogItem>())
                            .WriteTo.RollingFile(pathFormat: eventsPath,
                                fileSizeLimitBytes: 1073741824,
                                retainedFileCountLimit: 31));
loggerConfig.WriteTo.Logger(
                    lc =>
                        lc.Filter.ByExcluding(Matching.FromSource<ActivityLogItem>())
                            .WriteTo.RollingFile(pathFormat: activityPath,
                                fileSizeLimitBytes: 1073741824,
                                retainedFileCountLimit: 31));

_logger.Information("{@ActivityLogItem}", new ActivityLogItem());
_logger.Information("{@EventLogItem}", new EventLogItem());

When i'm logging with this configuration both files in both folders are generated but the files contain both the entries for the EventLogItem and the ActivityLogItem.

File: Activities\log-2016....log

2016-12-29 17:36:47.610 +01:00 [Information] EventLogItem { Id: 00000000-0000-0000-0000-000000000000, TimeStamp: 01/01/0001 00:00:00, Title: "Startup", Detail: "Starting up" } 2016-12-29 17:57:32.297

+01:00 [Information] ActivityLogItem { Ip: "::1", Port: "-1", UserAgent: "Mozilla/5.0", StartRequest: 12/29/2016 17:57:29, EndRequest: 12/29/2016 17:57:29 }

File: Events\log-2016....log

2016-12-29 17:36:47.610 +01:00 [Information] EventLogItem { Id: 00000000-0000-0000-0000-000000000000, TimeStamp: 01/01/0001 00:00:00, Title: "Startup", Detail: "Starting up" } 2016-12-29 17:57:32.297

+01:00 [Information] ActivityLogItem { Ip: "::1", Port: "-1", UserAgent: "Mozilla/5.0", StartRequest: 12/29/2016 17:57:29, EndRequest: 12/29/2016 17:57:29 }

I have also tried it with ByIncludingOnly at the Filter configuration, which resulted in the result that no file was generated.

How should my configuration look like that serilog will log on different files for a type?

Edit:

I have also tried it now by adding a Matching.WithProperty

In my class ActivityLogItem I have added a new property:

public int EType {get;set;} = 1;

and changed the configuration to

ByExcluding(Matching.WithProperty<int>("EType", p => p == 1)

which is also getting ignored. The logger writes both entries in both files specified.

Answer 1

The FromSource() filter identifies events raised by a particular logger:

_logger.ForContext<ActivityLogItem>()
     .Information("This would be picked up by the filters");

The WithProperty() filter looks at the direct properties on the log events, i.e. the names embedded in the message template like {@ActivityLogItem}. In your follow-up edit, the EType property is a nested property, so won't match the filter.

You could do the following if you want to use that approach:

_logger.Information("{EType} {@ActivityLogItem}", 1, new ActivityLogItem());

There are several ways to set up the filtering; I'd recommend the ForContext() approach if it is open to you. Alternatively, if you don't want to modify the logging statements, try:

Filter.ByExcluding(evt => evt.Properties.TryGetValue("ActivityLogItem"));