Provide capability to configure log verbosity (#553)

* Provide docs

* Provide capability to configure log verbosity

* PROMITOR_LOGGING_MINIMUMLOGLEVEL -> PROMITOR_LOGGING_MINIMUMLEVEL

* Docs - Change headers

docs/configuration/index.md

@@ -30,7 +30,13 @@ This information can be found on the newly created AD Application as documented
 
 The entity in the Azure AD needs to have `Monitoring Reader` permission on the resource group that will be queried. More information can be found [here](https://docs.microsoft.com/en-us/azure/monitoring-and-diagnostics/monitoring-roles-permissions-security).
 
-# Telemetry
+# Logging
+We provide insights in how our runtime is doing and is written to `stdout`.
+
+This can be controlled via the following environment variables:
+- **PROMITOR_LOGGING_MINIMUMLEVEL** - Defines the minimum log level that should be logged. If none is configured, `Warning` will be used. Allowed values are `Trace`, `Debug`, `Information`, `Warning`, `Error`, `Critical`, `None` ordered from most to least verbose.
+
+## External Providers
 Promitor can send telemetry to Azure Application Insights when there is a need to.
 
 It currently supports:

docs/index.md

@@ -47,7 +47,7 @@ And there is more on the way - Check our [backlog](https://github.com/tomkerkhov
     - [Runtime](configuration#runtime)
     - [Scraping](configuration#scraping)
     - [Authentication with Azure Monitor](configuration#authentication-with-azure-monitor)
-    - [Telemetry](configuration#telemetry)
+    - [Logging & External Providers](configuration#logging)
 - **Operations**
     - [Azure Resource Manager API - Consumption & Throttling](operations#azure-resource-manager-api---consumption--throttling)
     - [Health](operations#health)

src/Promitor.Core.Telemetry/Loggers/Logger.cs

@@ -0,0 +1,26 @@
+using System;
+using Microsoft.Extensions.Logging;
+using Microsoft.Extensions.Logging.Console;
+
+#pragma warning disable 618
+
+namespace Promitor.Core.Telemetry.Loggers
+{
+    public class Logger : ConsoleLogger
+    {
+        public Logger(string name) : base(name, (loggerName, logLevel) => IsFilteringRequired(logLevel), includeScopes: true)
+        {
+        }
+
+        private static bool IsFilteringRequired(LogLevel usedLogLevel)
+        {
+            var rawMinimalLogLevel = Environment.GetEnvironmentVariable(EnvironmentVariables.Logging.MinimumLogLevel);
+            if (Enum.TryParse(rawMinimalLogLevel, out LogLevel minimalLogLevel))
+            {
+                return minimalLogLevel <= usedLogLevel;
+            }
+
+            return LogLevel.Warning <= usedLogLevel;
+        }
+    }
+}

src/Promitor.Core.Telemetry/Loggers/RuntimeLogger.cs

@@ -0,0 +1,11 @@
+#pragma warning disable 618
+
+namespace Promitor.Core.Telemetry.Loggers
+{
+    public class RuntimeLogger : Logger
+    {
+        public RuntimeLogger() : base("Runtime")
+        {
+        }
+    }
+}

src/Promitor.Core.Telemetry/Loggers/ValidationLogger.cs

@@ -0,0 +1,11 @@
+#pragma warning disable 618
+
+namespace Promitor.Core.Telemetry.Loggers
+{
+    public class ValidationLogger : Logger
+    {
+        public ValidationLogger() : base("Validation")
+        {
+        }
+    }
+}

src/Promitor.Core/EnvironmentVariables.cs

@@ -28,5 +28,10 @@ public class Telemetry
         {
             public const string InstrumentationKey = "PROMITOR_TELEMETRY_INSTRUMENTATIONKEY";
         }
+
+        public class Logging
+        {
+            public const string MinimumLogLevel = "PROMITOR_LOGGING_MINIMUMLEVEL";
+        }
     }
 }

src/Promitor.Scraper.Host/Startup.cs

@@ -8,6 +8,7 @@
 using Promitor.Core.Scraping.Configuration.Providers.Interfaces;
 using Promitor.Core.Telemetry;
 using Promitor.Core.Telemetry.Interfaces;
+using Promitor.Core.Telemetry.Loggers;
 using Promitor.Core.Telemetry.Metrics;
 using Promitor.Core.Telemetry.Metrics.Interfaces;
 using Promitor.Scraper.Host.Extensions;

src/Promitor.Scraper.Host/Validation/RuntimeValidator.cs

@@ -1,8 +1,8 @@
 using System.Collections.Generic;
 using System.Linq;
 using Microsoft.Extensions.Logging;
-using Microsoft.Extensions.Logging.Console;
 using Promitor.Core.Scraping.Configuration.Providers;
+using Promitor.Core.Telemetry.Loggers;
 using Promitor.Scraper.Host.Validation.Exceptions;
 using Promitor.Scraper.Host.Validation.Interfaces;
 using Promitor.Scraper.Host.Validation.Steps;
@@ -17,7 +17,7 @@ public class RuntimeValidator
 
         public RuntimeValidator()
         {
-            _validationLogger = new ConsoleLogger("Validation", (message, logLevel) => true, includeScopes: true);
+            _validationLogger = new ValidationLogger();
 
             var scrapeConfigurationProvider = new MetricsDeclarationProvider(_validationLogger);
             _validationSteps = new List<IValidationStep>
@@ -31,7 +31,7 @@ public RuntimeValidator()
 
         public void Run()
         {
-            var validationLogger = new ConsoleLogger("Validation", (message, logLevel) => true, includeScopes: true);
+            var validationLogger = new ValidationLogger();
             validationLogger.LogInformation("Starting validation of Promitor setup");
 
             var validationResults = RunValidationSteps();

src/docker-compose.override.yml

@@ -8,6 +8,7 @@ services:
       - PROMITOR_AUTH_APPID=ceb249a3-44ce-4c90-8863-6776336f5b7e
       - PROMITOR_AUTH_APPKEY=ZgLy6zYNh9SEmIl0B+rv+ZuQQ2wJyQi/tTXnp2Wp9PM=
       - PROMITOR_TELEMETRY_INSTRUMENTATIONKEY=
+      - PROMITOR_LOGGING_MINIMUMLEVEL=Trace
       - "SECRETS_STORAGEQUEUE_SAS=?sv=2018-03-28&ss=bfqt&srt=sco&sp=rwdlacup&se=2019-07-28T02:33:14Z&st=2019-03-24T18:33:14Z&spr=https&sig=OiwNEYueCWlOhveapM1K6cRgV%2Be21gNhoq%2FDZqJEMZE%3D"
     ports:
       - "88"