Add environment variable to set minimum log level

Common/Phantom.Common.Logging/DefaultLogLevel.cs

@@ -0,0 +1,42 @@
+using System.Diagnostics.CodeAnalysis;
+using Serilog.Events;
+
+namespace Phantom.Common.Logging; 
+
+static class DefaultLogLevel {
+	private const string ENVIRONMENT_VARIABLE = "LOG_LEVEL";
+	
+	public static LogEventLevel Value { get; } = GetDefaultLevel();
+	
+	public static LogEventLevel Coerce(LogEventLevel level) {
+		return level < Value ? Value : level;
+	}
+	
+	private static LogEventLevel GetDefaultLevel() {
+		var level = Environment.GetEnvironmentVariable(ENVIRONMENT_VARIABLE);
+		return level switch {
+			"VERBOSE"     => LogEventLevel.Verbose,
+			"DEBUG"       => LogEventLevel.Debug,
+			"INFORMATION" => LogEventLevel.Information,
+			"WARNING"     => LogEventLevel.Warning,
+			"ERROR"       => LogEventLevel.Error,
+			null          => GetDefaultLevelFallback(),
+			_             => LogEnvironmentVariableErrorAndExit(level)
+		};
+	}
+
+	private static LogEventLevel GetDefaultLevelFallback() {
+		#if DEBUG
+		return LogEventLevel.Verbose;
+		#else
+		return LogEventLevel.Information;
+		#endif
+	}
+
+	[DoesNotReturn]
+	private static LogEventLevel LogEnvironmentVariableErrorAndExit(string logLevel) {
+		Console.Error.WriteLine("Invalid value of environment variable {0}: {1}", ENVIRONMENT_VARIABLE, logLevel);
+		Environment.Exit(1);
+		return LogEventLevel.Fatal;
+	}
+}

Common/Phantom.Common.Logging/PhantomLogger.cs

@@ -7,28 +7,21 @@ using Serilog.Sinks.SystemConsole.Themes;
 namespace Phantom.Common.Logging;
 
 public static class PhantomLogger {
-	public static Logger Root { get; } = CreateBaseLogger("[{Timestamp:HH:mm:ss} {Level:u}] {Message:lj}{NewLine}{Exception}");
-	private static Logger Base { get; } = CreateBaseLogger("[{Timestamp:HH:mm:ss} {Level:u}] [{Category}] {Message:lj}{NewLine}{Exception}");
-
-	private static LogEventLevel GetDefaultLevel() {
-		#if DEBUG
-		return LogEventLevel.Verbose;
-		#else
-		return LogEventLevel.Information;
-		#endif
+	public static Logger Root { get; } = CreateLogger("[{Timestamp:HH:mm:ss} {Level:u}] {Message:lj}{NewLine}{Exception}");
+	private static Logger Base { get; } = CreateLogger("[{Timestamp:HH:mm:ss} {Level:u}] [{Category}] {Message:lj}{NewLine}{Exception}");
+	
+	private static Logger CreateLogger(string template) {
+		return new LoggerConfiguration()
+		       .MinimumLevel.Is(DefaultLogLevel.Value)
+		       .MinimumLevel.Override("Microsoft", DefaultLogLevel.Coerce(LogEventLevel.Information))
+		       .MinimumLevel.Override("Microsoft.AspNetCore", DefaultLogLevel.Coerce(LogEventLevel.Warning))
+		       .MinimumLevel.Override("Microsoft.EntityFrameworkCore.Database.Command", DefaultLogLevel.Coerce(LogEventLevel.Warning))
+		       .Filter.ByExcluding(static e => e.Exception is OperationCanceledException)
+		       .Enrich.FromLogContext()
+		       .WriteTo.Console(outputTemplate: template, formatProvider: CultureInfo.InvariantCulture, theme: AnsiConsoleTheme.Literate)
+		       .CreateLogger();
 	}
 
-	private static Logger CreateBaseLogger(string template) =>
-		new LoggerConfiguration()
-			.MinimumLevel.Is(GetDefaultLevel())
-			.MinimumLevel.Override("Microsoft", LogEventLevel.Information)
-			.MinimumLevel.Override("Microsoft.AspNetCore", LogEventLevel.Warning)
-			.MinimumLevel.Override("Microsoft.EntityFrameworkCore.Database.Command", LogEventLevel.Warning)
-			.Filter.ByExcluding(static e => e.Exception is OperationCanceledException)
-			.Enrich.FromLogContext()
-			.WriteTo.Console(outputTemplate: template, formatProvider: CultureInfo.InvariantCulture, theme: AnsiConsoleTheme.Literate)
-			.CreateLogger();
-
 	public static ILogger Create(string name) {
 		return Base.ForContext("Category", name);
 	}

README.md

@@ -97,6 +97,18 @@ Use volumes to persist either the whole `/data` folder, or just `/data/data` if
   - `ALLOWED_SERVER_PORTS` is a comma-separated list of ports and port ranges that can be used as Minecraft Server ports. Example: `25565,25900,26000-27000`
   - `ALLOWED_RCON_PORTS` is a comma-separated list of ports and port ranges that can be used as Minecraft RCON ports. Example: `25575,25901,36000-37000`
 
+## Logging
+
+Both the Server and Agent support a `LOG_LEVEL` environment variable to set the minimum log level. Possible values:
+
+* `VERBOSE`
+* `DEBUG`
+* `INFORMATION`
+* `WARNING`
+* `ERROR`
+
+If the environment variable is omitted, the log level is set to `VERBOSE` for Debug builds and `INFORMATION` for Release builds.
+
 # Development
 
 The repository includes a [Rider](https://www.jetbrains.com/rider/) projects with several run configurations. The `.workdir` folder in the root of the repository is used for storage. Here's how to get started: