Json NLog Config

Loading from appsettings.json

Introduced with NLog.Extensions.Logging ver. 1.5.0

var config = new ConfigurationBuilder()
   .SetBasePath(System.IO.Directory.GetCurrentDirectory())
   .AddJsonFile("appsettings.json", optional: true, reloadOnChange: true)
   .Build();

LogManager.Configuration = new NLogLoggingConfiguration(config.GetSection("NLog"));

Simple Json NLog Config Example

{
    "NLog": {
        "throwConfigExceptions": true,
        "targets": {
            "logfile": {
                "type": "File",
                "fileName": "c:/temp/nlog-${shortdate}.log"
            },
            "logconsole": {
                "type": "Console",
            }
        },
        "rules": [
            {
                "logger": "*",
                "minLevel": "Info",
                "writeTo": "logconsole"
            },
            {
                "logger": "*",
                "minLevel": "Debug",
                "writeTo": "logfile"
            }
        ]
    }
}

Extended Json NLog Config Example

{
    "Logging": {
        "LogLevel": {
            "Default": "Debug"
        },
        "NLog": {
            "IncludeScopes": true,
        }
    },
    "NLog": {
        "autoReload": true,
        "throwConfigExceptions": true,
        "internalLogLevel": "info",
        "internalLogFile": "c:/temp/internal-nlog.txt",
        "extensions": {
            "NLog.Extensions.Logging": {
                "assembly": "NLog.Extensions.Logging"
            }
        },
        "variables": {
            "var_logdir": "c:/temp"
        },
        "default-wrapper": {
            "type": "AsyncWrapper",
            "overflowAction": "Block"
        },
        "targets": {
            "all-file": {
                "type": "File",
                "fileName": "${var_logdir}/nlog-all-${shortdate}.log",
                "layout": "${longdate}|${event-properties:item=EventId_Id:whenEmpty=0}|${uppercase:${level}}|${logger}|${message} ${exception:format=tostring}"
            },
            "own-console": {
                "type": "LimitingWrapper",
                "interval": "00:00:01",
                "messageLimit": 100,
                "target": {
                    "type": "Console",
                    "layout": "${longdate}|${event-properties:item=EventId_Id:whenEmpty=0}|${uppercase:${level}}|${logger}|${message} ${exception:format=tostring}|${callsite}"
                }
            }
        },
        "rules": [
            {
                "logger": "*",
                "minLevel": "Trace",
                "writeTo": "all-file"
            },
            {
                "logger": "Microsoft.*",
                "maxLevel": "Info",
                "final": true
            },
            {
                "logger": "*",
                "minLevel": "Debug",
                "writeTo": "own-console",
                "filters": {
                    "whenRepeated": {
                        "layout": "${message}",
                        "action": "Ignore"
                    }
                }
            }
        ]
    }
}

Environment specific configuration

ASP.NET Core uses the environment variable ASPNETCORE_ENVIRONMENT to configures app behavior based on the runtime environment. It also allows one to override appsettings for an environment:

• appsettings.json - Default settings
• appsettings.Production.json - Production specific settings.
• appsettings.Development.json - Development specific settings.

This an also be used for the NLog-config, so one can have special NLog targets for a certain environment.

SplitGroup Target Wrapper

The SplitGroup-target-wrapper can be used to introduce extra NLog-target output without changing logging-rules.

Logging Rule Override

Example of how one can override logging-rule "0" and introduce an additional logging-rule.

Note one can also use more readable names instead of "0". Ex. call them "00_ErrorLog", "01_DebugFile". It is important to keep the prefix because the order of NLog Logging Rules is important (Ex. final-rules).

appsettings.json

        "rules": {
            "0": {
                "logger": "*",
                "minLevel": "Error",
                "writeTo": "errorFile,errorEmail"
            },
            "1": {
                "logger": "*",
                "minLevel": "Debug",
                "writeTo": "debugFile"
            }
        }

appsettings.development.json

        "rules": {
            "0": {
                "logger": "*",
                "minLevel": "Error",
                "writeTo": "errorFile"
            },
            "2": {
                "logger": "*",
                "minLevel": "Debug",
                "writeTo": "debugConsole"
            }
        }