无法使用通过DI提供的ILogger实例 [英] Unable to use ILogger instance provided via DI
问题描述
从本质上讲，有两种方法可以获取ILogger实例。
Essentially, there are two different ways I get ILogger instances. One works perfectly fine, the other doesn't.
我有这样的Azure函数：
I have an Azure Function like this:
class AzureFunctionClass {
private readonly ISomeClass _someclass;
public AzureFunctionClass(ISomeClass someClass){
_someclass = someClass;
}
public Task<IActionResult> AzureFunction(ILogger log){
log.LogInformation("This works, I see this message when run");
_someclass.ExecuteMethod();
}
}
另一个类，不包含Azure函数，例如：
Another class, not containing Azure functions, like this:
class SomeClass : ISomeClass {
private readonly ILogger<SomeClass> _log;
public SomeClass(ILogger log){
_log = log;
}
public void ExecuteMethod(){
_log.LogInformation("This doesn't crash so _log isn't null, but it
doesn't write anything");
}
}
Startup.cs：
Startup.cs:
class Startup : IWebJobsStartup {
public void Configure(IWebJobsBuilder builder){
builder.Services.AddScoped<ISomeClass, SomeClass>();
builder.Services.AddTransient(typeof(ILogger<>), typeof(Logger<>));
builder.Services.AddScoped<ILogger<SomeClass>, Logger<SomeClass>>();
}
}
不，我担心AzureFunctionClass不能仅仅将其ILogger实例作为参数传递给ISomeClass。
我还到处都在寻找日志文件，例如在Azure Storage Explorer中，以查看它是否只是没有写入Azure Portal控制台。我发现的每个日志文件都有上述工作情况的日志，而没有其他情况的日志。
And no, I'm afraid that AzureFunctionClass cannot just pass its ILogger instance to ISomeClass as a parameter. I've also looked everywhere for log files, such as in Azure Storage Explorer, to see if it's possibly just not writing to the Azure Portal console. Every log file I found had logs for the working case described above, and none of them had logs for the other case.
推荐答案
目前，函数运行时存在一个错误，由于该错误，它会过滤掉任何以不以字符串 Function开头的类别创建的日志。。
At present, the function runtime has a bug due to which it filters out any log that is created with a category that doesn't start with string Function..
查看以下GitHub问题：
See these GitHub issues:
- #4425 - ILogger is not injected when using new DI functionality
- #4345 - Remove filters for ILoggers created by customer DI
在函数方法中注入的记录器由函数运行时完成，该运行时将创建类别设置为 Type.FullName （在您的示例中为type情况是 SomeClass ）。因为它的全名不是以 Function 开头，所以用该类别记录的行将被过滤掉。
The logger injected in the function method is done by the function runtime which creates the logger with category set to Function.<FunctionName>.User. So this gets logged properly. But the logger that is injected into the constructor is done by the asp.net core DI framework, which sets the category name for the logger as Type.FullName (type in your example case is SomeClass). Because it's fullname doesn't start with Function, the lines logged with this category are filtered out.
有解决此问题的两种方法。
There are two ways to workaround this.
选项1：更改host.json以不从名称空间中过滤日志
{
"version": "2.0",
"logging": {
"logLevel": {
"<YourNameSpace>": "Information"
}
}
}
选项2：在您的ctor中插入ILoggerFactory，并创建一个类别不会被过滤的记录器
class SomeClass : ISomeClass {
private readonly ILogger _log;
public SomeClass(ILoggerFactory loggerFactory){ // Note that we inject ILoggerFactory
this._log = loggerFactory.CreateLogger(
LogCategories.CreateFunctionUserCategory(this.GetType().FullName)); // Must use CreateFunctionUserCategory to create the log category name otherwise the log gets filtered out.
}
public void ExecuteMethod(){
_log.LogInformation("This should get logged correctly.");
}
}
请注意，ILogger已通过以下方式注册到DI框架中：函数运行时（如NKosi的答案所述），因此可以删除这些行。
Note that, ILogger is already registered into DI framework by the function runtime (as mentioned in NKosi's answer), so those lines can be removed.
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