Sanitize overlapping property names (#97)

* Added sanitizing for overlapping property names

* Property name sanitizing test added

* Updated README.MD

* Added README.MD to package

Author: mishamyte

README.md

@@ -1,5 +1,6 @@
 # Serilog.Sinks.Grafana.Loki
 
+[![Made in Ukraine](https://img.shields.io/badge/made_in-ukraine-ffd700.svg?labelColor=0057b7)](https://stand-with-ukraine.pp.ua/)
 [![Build status](https://github.com/mishamyte/serilog-sinks-grafana-loki/workflows/CI/badge.svg)](https://github.com/mishamyte/serilog-sinks-grafana-loki/actions?query=workflow%3ACI)
 [![NuGet version](https://img.shields.io/nuget/v/Serilog.Sinks.Grafana.Loki)](https://www.nuget.org/packages/Serilog.Sinks.Grafana.Loki)
 [![Latest release](https://img.shields.io/github/v/release/mishamyte/serilog-sinks-grafana-loki?include_prereleases)](https://github.com/mishamyte/serilog-sinks-grafana-loki/releases)
@@ -160,4 +161,4 @@ Example configuration:
 ```
 
 ### Inspiration and Credits
-- [Serilog.Sinks.Loki](https://github.com/JosephWoodward/Serilog-Sinks-Loki)
+- [Serilog.Sinks.Loki](https://github.com/JosephWoodward/Serilog-Sinks-Loki)

src/Serilog.Sinks.Grafana.Loki/LokiJsonTextFormatter.cs

@@ -24,9 +24,14 @@ namespace Serilog.Sinks.Grafana.Loki
     /// <summary>
     /// Used to serialize a log event to a json format that loki 2.0 can parse using the json parser ( | json ), more information can be found here https://grafana.com/blog/2020/10/28/loki-2.0-released-transform-logs-as-youre-querying-them-and-set-up-alerts-within-loki/
     /// </summary>
-    [SuppressMessage("ReSharper", "PossibleMultipleEnumeration", Justification = "Reviewed")]
+    [SuppressMessage(
+        "ReSharper",
+        "PossibleMultipleEnumeration",
+        Justification = "Reviewed")]
     public class LokiJsonTextFormatter : ITextFormatter, ILabelAwareTextFormatter
     {
+        private static readonly string[] ReservedKeywords = { "Message", "MessageTemplate", "Renderings", "level", "Exception" };
+
         private readonly JsonValueFormatter _valueFormatter;
 
         /// <summary>
@@ -52,7 +57,10 @@ public LokiJsonTextFormatter()
         /// <param name="labels">
         /// List of labels that should not be written as json fields.
         /// </param>
-        public void Format(LogEvent logEvent, TextWriter output, IEnumerable<string> labels)
+        public void Format(
+            LogEvent logEvent,
+            TextWriter output,
+            IEnumerable<string> labels)
         {
             if (logEvent == null)
             {
@@ -98,12 +106,15 @@ public void Format(LogEvent logEvent, TextWriter output, IEnumerable<string> lab
             if (logEvent.Exception != null)
             {
                 output.Write(",\"Exception\":");
-                SerializeException(output, logEvent.Exception, 1);
+                SerializeException(
+                    output,
+                    logEvent.Exception,
+                    1);
             }
 
             foreach (var property in logEvent.Properties)
             {
-                var name = property.Key;
+                var name = GetSanitizedPropertyName(property.Key);
                 if (labels.Contains(name))
                 {
                     continue;
@@ -120,7 +131,20 @@ public void Format(LogEvent logEvent, TextWriter output, IEnumerable<string> lab
 
         /// <inheritdoc/>
         [Obsolete("Use \"Format(LogEvent logEvent, TextWriter output, IEnumerable<string> labels)\" instead!")]
-        public void Format(LogEvent logEvent, TextWriter output) => Format(logEvent, output, Enumerable.Empty<string>());
+        public void Format(LogEvent logEvent, TextWriter output) => Format(
+            logEvent,
+            output,
+            Enumerable.Empty<string>());
+
+        /// <summary>
+        /// Used to sanitize property name to avoid conflict with reserved keywords.
+        /// Appends _ to the property name if it matches with reserved keyword.
+        /// </summary>
+        /// <param name="propertyName">
+        /// Name of property to sanitize
+        /// </param>
+        protected virtual string GetSanitizedPropertyName(string propertyName) =>
+            ReservedKeywords.Contains(propertyName) ? $"_{propertyName}" : propertyName;
 
         /// <summary>
         /// Used to serialize exceptions, can be overridden when inheriting to change the format.
@@ -134,17 +158,23 @@ public void Format(LogEvent logEvent, TextWriter output, IEnumerable<string> lab
         /// <param name="level">
         /// The current nesting level of the exception.
         /// </param>
-        protected virtual void SerializeException(TextWriter output, Exception exception, int level)
+        protected virtual void SerializeException(
+            TextWriter output,
+            Exception exception,
+            int level)
         {
             if (level == 4)
             {
                 JsonValueFormatter.WriteQuotedJsonString(exception.ToString(), output);
+
                 return;
             }
 
             output.Write("{\"Type\":");
             var typeNamespace = exception.GetType().Namespace;
-            var typeName = typeNamespace != null && typeNamespace.StartsWith("System.") ? exception.GetType().Name : exception.GetType().ToString();
+            var typeName = typeNamespace != null && typeNamespace.StartsWith("System.")
+                ? exception.GetType().Name
+                : exception.GetType().ToString();
             JsonValueFormatter.WriteQuotedJsonString(typeName, output);
 
             if (!string.IsNullOrWhiteSpace(exception.Message))
@@ -166,7 +196,10 @@ protected virtual void SerializeException(TextWriter output, Exception exception
                 for (var i = 0; i < count; i++)
                 {
                     var isLast = i == count - 1;
-                    SerializeException(output, aggregateException.InnerExceptions[i], level + 1);
+                    SerializeException(
+                        output,
+                        aggregateException.InnerExceptions[i],
+                        level + 1);
                     if (!isLast)
                     {
                         output.Write(',');
@@ -178,10 +211,13 @@ protected virtual void SerializeException(TextWriter output, Exception exception
             else if (exception.InnerException != null)
             {
                 output.Write(",\"InnerException\":");
-                SerializeException(output, exception.InnerException, level + 1);
+                SerializeException(
+                    output,
+                    exception.InnerException,
+                    level + 1);
             }
 
             output.Write('}');
         }
     }
-}
+}

src/Serilog.Sinks.Grafana.Loki/Serilog.Sinks.Grafana.Loki.csproj

@@ -17,6 +17,7 @@
         <PackageId>Serilog.Sinks.Grafana.Loki</PackageId>
         <PackageLicenseFile>LICENSE</PackageLicenseFile>
         <PackageProjectUrl>https://github.com/mishamyte/serilog-sinks-grafana-loki</PackageProjectUrl>
+        <PackageReadmeFile>README.md</PackageReadmeFile>
         <PackageReleaseNotes>For release notes, please see the change log on GitHub.</PackageReleaseNotes>
         <PackageTags>serilog;loki;grafana</PackageTags>
     </PropertyGroup>
@@ -28,7 +29,8 @@
 
     <ItemGroup>
         <None Include="..\..\LICENSE" Pack="true" Visible="false" PackagePath="" />
+        <None Include="..\..\README.md" Pack="true" Visible="false" PackagePath="" />
         <None Include="..\..\assets\serilog-sink-nuget.png" Pack="true" Visible="false" PackagePath="" />
     </ItemGroup>
 
-</Project>
+</Project>

test/Serilog.Sinks.Grafana.Loki.Tests/IntegrationTests/Approvals/LokiJsonTextFormatterRequestPayloadTests.PropertyNameEqualToReservedKeywordShouldBeSanitized.approved.txt

@@ -0,0 +1 @@
+{"streams":[{"stream":{"Message":"Ukraine!"},"values":[["<unixepochinnanoseconds>","{\u0022Message\u0022:\u0022This is \\\u0022Ukraine!\\\u0022\u0022,\u0022MessageTemplate\u0022:\u0022This is {Message}\u0022,\u0022level\u0022:\u0022info\u0022,\u0022_Message\u0022:\u0022Ukraine!\u0022}"]]}]}

test/Serilog.Sinks.Grafana.Loki.Tests/IntegrationTests/LokiJsonTextFormatterRequestPayloadTests.cs

@@ -211,5 +211,26 @@ public void MessagePropertyForInternalTimestampShouldBeCreated()
                 });
             });
         }
+
+        [Fact]
+        public void PropertyNameEqualToReservedKeywordShouldBeSanitized()
+        {
+            var logger = new LoggerConfiguration()
+                .WriteTo.GrafanaLoki(
+                    "https://loki:3100",
+                    outputTemplate: OutputTemplate,
+                    textFormatter: new LokiJsonTextFormatter(),
+                    httpClient: _client)
+                .CreateLogger();
+
+            logger.Information("This is {Message}", "Ukraine!");
+            logger.Dispose();
+
+            _client.Content.ShouldMatchApproved(c =>
+            {
+                c.SubFolder(ApprovalsFolderName);
+                c.WithScrubber(s => Regex.Replace(s, "\"[0-9]{19}\"", "\"<unixepochinnanoseconds>\""));
+            });
+        }
     }
 }