循序渐进学.Net Core Web Api开发系列【10】:使用日志

原文:循序渐进学.Net Core Web Api开发系列【10】:使用日志

系列目录

循序渐进学.Net Core Web Api开发系列目录

 本系列涉及到的源码下载地址:https://github.com/seabluescn/Blog_WebApi

一、本篇概述

本篇介绍日志的使用,包括系统默认的控制台日志和第三方NLog日志管理。

二、使用系统控制台日志

1、使用内置日志

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    [Produces("application/json")]
    [Route("api/Article")]
    public class ArticleController : Controller
    {      private readonly ILogger _logger;
        public ArticleController(SalesContext context, ILogger<ArticleController> logger)
        {          
            _logger = logger;
        }       
    [HttpGet(</span><span style="color: #800000;">"</span><span style="color: #800000;">logger</span><span style="color: #800000;">"</span><span style="color: #000000;">)]
    </span><span style="color: #0000ff;">public</span> <span style="color: #0000ff;">void</span> TestLogger(<span style="color: #000000;">)
    {</span><span style="color: #000000;">
        _logger.LogCritical(</span><span style="color: #800000;">"</span><span style="color: #800000;">LogCritical</span><span style="color: #800000;">"</span><span style="color: #000000;">);
        _logger.LogError(</span><span style="color: #800000;">"</span><span style="color: #800000;">LogError</span><span style="color: #800000;">"</span><span style="color: #000000;">);          
        _logger.LogWarning(</span><span style="color: #800000;">"</span><span style="color: #800000;">LogWarning</span><span style="color: #800000;">"</span><span style="color: #000000;">);
        _logger.LogInformation(</span><span style="color: #800000;">"</span><span style="color: #800000;">LogInformation</span><span style="color: #800000;">"</span><span style="color: #000000;">);
        _logger.LogDebug(</span><span style="color: #800000;">"</span><span style="color: #800000;">LogDebug</span><span style="color: #800000;">"</span><span style="color: #000000;">);

        </span><span style="color: #0000ff;">return</span><span style="color: #000000;">;
    }
}</span></pre>
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默认只能看到前三条记录:

主要原因是日志的最低级别默认为Warring,如果要显示其他级别日志,需要修改application.json文件。 

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  "Logging": {
    "IncludeScopes": false,
    "Debug": {
      "LogLevel": {
        "Default": "Error"
      }
    },
    "Console": {
      "LogLevel": {
        "Default": "Information"
      }
    }
  }
}

日志级别优先级如下顺序:

Critical > Error > Warning > Information > Debug

调整日志级别为Information 或Debug以后会显示太多无关的日志信息,可以配置默认级别为Warring,而自己项目命名空间的日志级别为Debug。

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"Console": {
      "LogLevel": {
        "Default": "Warning",
        "SaleService.Controllers": "DEBUG"
      }
    }

2、几点说明

1)目前日志已经可以正常工作了,把项目发布到Linux环境下,通过配置Supervisor可以把控制台的内容输出到文件系统,建议在调试环境下采用Debug日志级别,而在生成环境采用Error日志级别。配置Supervisor的内容可以参考:循序渐进学.Net Core Web Api开发系列【7】:项目发布

 2)如果稍微了解依赖注入(DI)的知识,就可以理解我们在Controoler中使用ILogger是采用标准的构造函数注入的方式,但是问题是用户并没有注册该服务,其实是系统在CreateDefaultBuilder时帮我们注册了日志服务。可以看几段源码的片段:

CreateDefaultBuilder:
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using System;
using System.IO;
using System.Reflection;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Routing;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;

namespace Microsoft.AspNetCore
{

public static class WebHost
{

public static IWebHostBuilder CreateDefaultBuilder(string[] args)
{
return WebHostBuilderIISExtensions.UseIISIntegration(HostingAbstractionsWebHostBuilderExtensions.UseContentRoot(WebHostBuilderKestrelExtensions.UseKestrel(new WebHostBuilder()), Directory.GetCurrentDirectory()).ConfigureAppConfiguration(delegate(WebHostBuilderContext hostingContext, IConfigurationBuilder config)
{
IHostingEnvironment hostingEnvironment
= hostingContext.HostingEnvironment;
JsonConfigurationExtensions.AddJsonFile(JsonConfigurationExtensions.AddJsonFile(config,
"appsettings.json", true, true), string.Format("appsettings.{0}.json", hostingEnvironment.EnvironmentName), true, true);
if (HostingEnvironmentExtensions.IsDevelopment(hostingEnvironment))
{
Assembly assembly
= Assembly.Load(new AssemblyName(hostingEnvironment.ApplicationName));
if (assembly != null)
{
UserSecretsConfigurationExtensions.AddUserSecrets(config, assembly,
true);
}
}
EnvironmentVariablesExtensions.AddEnvironmentVariables(config);
if (args != null)
{
CommandLineConfigurationExtensions.AddCommandLine(config, args);
}
}).ConfigureLogging(
delegate(WebHostBuilderContext hostingContext, ILoggingBuilder logging)
{
LoggingBuilderExtensions.AddConfiguration(logging, hostingContext.Configuration.GetSection(
"Logging"));
logging.AddConsole();
logging.AddDebug();

})).UseDefaultServiceProvider(
delegate(WebHostBuilderContext context, ServiceProviderOptions options)
{
options.ValidateScopes
= HostingEnvironmentExtensions.IsDevelopment(context.HostingEnvironment);
});
}
}
}

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AddConsole:
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using System;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging.Console;

namespace Microsoft.Extensions.Logging
{

public static class ConsoleLoggerExtensions
{

public static ILoggingBuilder AddConsole(this ILoggingBuilder builder)
{
builder.Services.AddSingleton
<ILoggerProvider, ConsoleLoggerProvider>();
return builder;
}

}
}

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三、使用NLog

1、通过NuGet获取包:NLog.Web.AspNetCore

2、修改Startup类的Configure方法:

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 public class Startup
    {
        public Startup(IConfiguration configuration)
        {
            Configuration = configuration;
        }
        public IConfiguration Configuration { get; }       

// This method gets called by the runtime. Use this method to configure the HTTP request pipeline. public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory) { loggerFactory.AddNLog(); loggerFactory.ConfigureNLog("nlog.config"); //如果采用默认配置文件nlog.config,该语句可以省略 } }
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nlog.config配置文件内容如下:

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<?xml version="1.0" encoding="utf-8"?>
<nlog xmlns="http://www.nlog-project.org/schemas/NLog.xsd"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
  <targets>
    <target xsi:type="File" name="logfile" fileName="${basedir}/logs/${shortdate}_all.log" keepFileOpen="false" layout="${longdate}|${callsite:fileName=True}|${uppercase:${level}}|${message} ${exception}" />
    <target xsi:type="File" name="debugfile" fileName="${basedir}/logs/${shortdate}_debug.log" keepFileOpen="false" layout="${longdate}|${callsite:fileName=True}|${uppercase:${level}}|${message} ${exception}" />
    <target xsi:type="File" name="errfile" fileName="${basedir}/logs/${shortdate}_error.log" keepFileOpen="false" layout="${longdate}|${callsite:fileName=True}|${uppercase:${level}}|${message} ${exception}" />
  </targets>
  <rules>
    <logger name="*" level="Debug" writeTo="debugfile" />
    <logger name="*" level="Error" writeTo="errfile" />   
    <logger name="*" minlevel="Trace" writeTo="logfile" />
  </rules>
</nlog>

项目发布时修改配置文件,只保留errfile即可。

以上就是全部代码,Controller中的代码无需修改。

3、两个注意点

1)目前我们已经采用NLog来进行日志的记录,此时系统默认的日志仍然是正常工作的,项目发布时建议把系统默认的日志级别改成Error,nlog的输出日志只保留errfile,以免造成服务器磁盘空间浪费。

2)项目发布时nlog.config文件可能不会发布到目标目录,需要修改该文件的文件属性:

原文地址:https://www.cnblogs.com/owenzh/p/11207069.html