CODEWITHSUNDEEP
logging.net-coreserilog
Tomas Aschan
Tomas Aschan

Reputation: 60634

How do I filter my log file based on categories with .NET Core logging?

I've configured my logger factory like so,

loggerFactory
    .AddConsole()
    .AddDebug()
    .AddFile("Logs/trace-{Date}.txt");

and in my constructors I take dependencies on e.g. ILogger<MyServiceClass>. It is my understanding that the framework will then create a logger instance for my service class, with a category name based on the full name of the type.

In my log file, I see messages like this:

2017-07-07T09:10:46.5678506+02:00 0HL650T1MS1RU [WRN] Socket registration failed for participant b943174e-8022-4e33-ef0d-08d4c4bc4879 in negotiation 42d9720f-32a2-46f9-9042-08d4c4bc4881. (799c4f21)

I seem to remember reading somewhere that the category is hashed to save on file size, so I suspect the mouthful between the timestamp and the log level (0HL...1RU) represents the category, but that's not really searchable or discoverable.

How do I configure my logger to not obfuscate the category names in the log file?

Upvotes: 3

Views: 1192

Answers (2)

Michael Mahair II
Michael Mahair II

Reputation: 1

You can add the log category by using {SourceContext} in the outputTemplate, like so:

loggerFactory
    .AddConsole()
    .AddDebug()
    .AddFile(
        "Logs/trace-{Date}.txt",
        , outputTemplate: "{Timestamp:o} {RequestId,13} [{Level:u3}] {SourceContext} {Message} ({EventId:x8}){NewLine}{Exception}"
    );

Upvotes: 0

Ilya Chumakov
Ilya Chumakov

Reputation: 25039

According to the code, you use Serilog.Extensions.Logging.File (the concrete logger implementation is important). That funny string 0HL...1RU actually is a unique Request Id. I guess this logger doesn't support log categories for the plain text logs.

Workaround #1: use JSON logs:

loggerFactory.AddFile("filename", isJson: true);

SourceContext property will appear in the log output having your log category:

"SourceContext":"MyNamespace.MyServiceClass"

Workaround #2: just use another third-party file logger like NLog or full standalone Serilog API.

Upvotes: 2

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