Logging

dbExpression supports the logging abstractions provided in Microsoft's logging framework.
A few dbExpression services support ILogger, where an instance of ILogger is injected into the service.

dbExpression generally logs as follows for the different log levels:

Trace: emits low-level messages that help resolve any issues you may be having with dbExpression. As recommended just about everywhere, do not use this level in production.
Debug: dbExpression only emits rendered sql statements prior to execution against the database.
Info: at application startup, dbExpression will emit a message for each configured database noting that the database is ready for use. If the database was configured to be used statically, an additional message will be emitted indicating so.
Warn, Error, and Critical: dbExpression does not emit any log messages, in these cases exceptions will be thrown and it is up to you to log messages.

It is highly recommended to turn dbExpression logging "off" in production and use it only when developing your application.

Through the runtime configuration of a database with dbExpression, logging settings can be set indicating whether to emit parameter values to logs. By default, this value is false and no parameter values will be emitted to logs. Parameter logging is an opt-in feature.

By default, dbExpression will NOT log parameter values to logs.

In the following, logging is configured via addition to the service collectioin. MyOtherDatabase does not contain any sensitive data, so it is configured to allow logging of parameter values. MyDatabase will log messages, but will not log parameter values.

...
services.AddLogging(builder =>
    {
        builder.ClearProviders();
        builder.AddConsole();
        builder.SetMinimumLevel(LogLevel.Debug);
    });
...

services.AddDbExpression(
    dbex => dbex.AddDatabase<MyDatabase>(
        db => db.ConnectionString.Use(config.GetConnectionString("MyDatabase"))
    ),
    dbex => dbex.AddDatabase<MyOtherDatabase>(
        db =>
        {
            db.ConnectionString.Use(config.GetConnectionString("MyOtherDatabase"));
            db.Logging.ConfigureLoggingOptions(l => l.LogParameterValues = true); 
                                                // ^ safe to log parameter values
        }
    );
);

...

With this, both databases will emit debug (and higher) level messages to the logger. To "turn off" logging in dbExpression, a filter needs to be added to the AddLogging(...) method:

services.AddLogging(builder =>
    {
        builder.ClearProviders();
        builder.AddConsole();
        builder.SetMinimumLevel(LogLevel.Debug);
        builder.AddFilter("DbExpression.*", level => false);
    });

dbExpression will still emit the Info messsages at application startup.