Add a flag to specify the log level

README.md

@@ -25,13 +25,22 @@ Add `Microsoft.DotNet.Watcher.Tools` to the `tools` section of your `project.jso
 
 Add `watch` after `dotnet` in the command that you want to run:
    
-| What you want to run                           | Dotnet watch command                                          |
+| What you want to run                           | Dotnet watch command                                     |
 | ---------------------------------------------- | -------------------------------------------------------- |
 | dotnet run                                     | dotnet **watch** run                                     |
 | dotnet run --arg1 value1                       | dotnet **watch** run --arg1 value                        |
 | dotnet run --framework net451 -- --arg1 value1 | dotnet **watch** run --framework net451 -- --arg1 value1 |
 | dotnet test                                    | dotnet **watch** test                                    |
 
+### Advanced configuration options
+
+Configuration options can be passed to `dotnet watch` through environment variables. The available variables are:
+
+| Variable                                       | Effect                                                   |
+| ---------------------------------------------- | -------------------------------------------------------- |
+| DOTNET_USE_POLLING_FILE_WATCHER                | If set to "1" or "true", `dotnet watch` will use a polling file watcher instead of CoreFx's `FileSystemWatcher`. Used when watching files on network shares or Docker mounted volumes.                       |
+| DOTNET_WATCH_LOG_LEVEL                         | Used to set the logging level for messages coming from `dotnet watch`. Accepted values `None`, `Trace`, `Debug`, `Information`, `Warning`, `Error`, `Critical`. Default: `Information`. |
+
 AppVeyor: [![AppVeyor](https://ci.appveyor.com/api/projects/status/fxhto3omtehio3aj/branch/dev?svg=true)](https://ci.appveyor.com/project/aspnetci/dnx-watch/branch/dev)
 
 Travis:   [![Travis](https://travis-ci.org/aspnet/dotnet-watch.svg?branch=dev)](https://travis-ci.org/aspnet/dotnet-watch)

src/Microsoft.DotNet.Watcher.Tools/Program.cs

@@ -19,7 +19,18 @@ namespace Microsoft.DotNet.Watcher.Tools
         {
             _loggerFactory = new LoggerFactory();
 
-            var commandProvider = new CommandOutputProvider();
+            var logVar = Environment.GetEnvironmentVariable("DOTNET_WATCH_LOG_LEVEL");
+
+            LogLevel logLevel;
+            if (string.IsNullOrEmpty(logVar) || !Enum.TryParse<LogLevel>(logVar, out logLevel))
+            {
+                logLevel = LogLevel.Information;
+            }
+
+            var commandProvider = new CommandOutputProvider()
+            {
+                LogLevel = logLevel
+            };
             _loggerFactory.AddProvider(commandProvider);
         }
 
@@ -32,7 +43,7 @@ namespace Microsoft.DotNet.Watcher.Tools
                     ctrlCTokenSource.Cancel();
                     ev.Cancel = false;
                 };
-                
+
                 return new Program().MainInternal(args, ctrlCTokenSource.Token);
             }
         }
@@ -44,7 +55,7 @@ namespace Microsoft.DotNet.Watcher.Tools
             app.FullName = "Microsoft dotnet File Watcher";
 
             app.HelpOption("-?|-h|--help");
- 
+
             app.OnExecute(() =>
             {
                 var projectToWatch = Path.Combine(Directory.GetCurrentDirectory(), ProjectModel.Project.FileName);