Update healthcheck unhealthy log to use JSON (#11380)

* Update healthcheck unhealthy log to use JSON Use custom JSON converter to write health entries log Add comments explaining JSON wrapper Remove accidental changes * Fix log test assertions

Author: jviau

src/WebJobs.Script/Diagnostics/HealthChecks/TelemetryHealthCheckPublisher.cs

@@ -1,12 +1,12 @@
-// Copyright (c) .NET Foundation. All rights reserved.
+// Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the MIT License. See License.txt in the project root for license information.
 
 using System;
 using System.Linq;
-using System.Text;
+using System.Text.Json;
+using System.Text.Json.Serialization;
 using System.Threading;
 using System.Threading.Tasks;
-using Microsoft.Azure.WebJobs.Script.Pools;
 using Microsoft.Extensions.Diagnostics.HealthChecks;
 using Microsoft.Extensions.Logging;
 
@@ -58,29 +58,15 @@ public Task PublishAsync(HealthReport report, CancellationToken cancellationToke
  }
  else
  {
- // Construct string showing list of all health entries status and description for logs
- using PoolRental<StringBuilder> rental = PoolFactory.SharedStringBuilderPool.Rent();
- string separator = string.Empty;
  foreach (var entry in report.Entries)
  {
  if (entry.Value.Status != HealthStatus.Healthy)
  {
  _metrics.UnhealthyHealthCheck.Record(entry.Key, entry.Value, tag);
  }
-
- rental.Value.Append(separator)
- .Append(entry.Key)
- .Append(": {")
- .Append("status: ")
- .Append(entry.Value.Status.ToString())
- .Append(", description: ")
- .Append(entry.Value.Description)
- .Append('}');
-
- separator = ", ";
  }
 
- Log.Unhealthy(_logger, tag, report.Status, rental.Value);
+ Log.Unhealthy(_logger, tag, report.Status, new HealthEntries(report));
  }
 
  _metrics.HealthCheckReport.Record(report, tag);
@@ -92,14 +78,60 @@ private bool FilterForTag(string name, HealthReportEntry entry)
  return entry.Tags.Contains(_options.Tag);
  }
 
- internal static partial class Log
+ /// <summary>
+ /// Wraps the health report entries for logging purposes.
+ /// </summary>
+ /// <param name="report">The report to log.</param>
+ /// <remarks>
+ /// By wrapping in a struct, we delay performing JSON serialization
+ /// until this is actually being logged (and not when it is filtered out).
+ /// </remarks>
+ private readonly struct HealthEntries(HealthReport report)
+ {
+ private static readonly JsonSerializerOptions _options
+ = new() { Converters = { new HealthEntriesConverter() } };
+
+ public override string ToString()
+ {
+ // We use a JSON serializer here to ensure proper escaping of values.
+ return JsonSerializer.Serialize(report, _options);
+ }
+ }
+
+ private class HealthEntriesConverter : JsonConverter<HealthReport>
+ {
+ public override HealthReport Read(
+ ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
+ {
+ throw new NotImplementedException();
+ }
+
+ public override void Write(
+ Utf8JsonWriter writer, HealthReport value, JsonSerializerOptions options)
+ {
+ writer.WriteStartObject();
+
+ foreach ((string name, HealthReportEntry entry) in value.Entries)
+ {
+ writer.WritePropertyName(name);
+ writer.WriteStartObject();
+ writer.WriteString("status", entry.Status.ToString());
+ writer.WriteString("description", entry.Description);
+ writer.WriteEndObject();
+ }
+
+ writer.WriteEndObject();
+ }
+ }
+
+ private static partial class Log
  {
  [LoggerMessage(0, LogLevel.Warning, "[Tag='{Tag}'] Process reporting unhealthy: {Status}. Health check entries are {Entries}")]
  public static partial void Unhealthy(
  ILogger logger,
  string tag,
  HealthStatus status,
- StringBuilder entries);
+ HealthEntries entries);
 
  [LoggerMessage(1, LogLevel.Debug, "[Tag='{Tag}'] Process reporting healthy: {Status}.")]
  public static partial void Healthy(

test/WebJobs.Script.Tests/Diagnostics/HealthChecks/TelemetryHealthCheckPublisherTests.cs

@@ -1,4 +1,4 @@
-// Copyright (c) .NET Foundation. All rights reserved.
+// Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the MIT License. See License.txt in the project root for license information.
 
 using System;
@@ -33,15 +33,17 @@ public class TelemetryHealthCheckPublisherTests
  CreateOptions(true, null),
  [HealthStatus.Degraded],
  1,
- "Process reporting unhealthy: Degraded. Health check entries are id0: {status: Degraded, description: desc0}",
+ @"Process reporting unhealthy: Degraded. Health check entries are " +
+ @"{""id0"":{""status"":""Degraded"",""description"":""desc0""}}",
  LogLevel.Warning,
  0.5
  },
  {
  CreateOptions(false, null),
  [HealthStatus.Unhealthy],
  1,
- "Process reporting unhealthy: Unhealthy. Health check entries are id0: {status: Unhealthy, description: desc0}",
+ "Process reporting unhealthy: Unhealthy. Health check entries are "
+ + @"{""id0"":{""status"":""Unhealthy"",""description"":""desc0""}}",
  LogLevel.Warning,
  0
  },
@@ -57,15 +59,17 @@ public class TelemetryHealthCheckPublisherTests
  CreateOptions(true, null),
  [HealthStatus.Healthy, HealthStatus.Unhealthy],
  1,
- "Process reporting unhealthy: Unhealthy. Health check entries are id0: {status: Healthy, description: desc0}, id1: {status: Unhealthy, description: desc1}",
+ "Process reporting unhealthy: Unhealthy. Health check entries are "
+ + @"{""id0"":{""status"":""Healthy"",""description"":""desc0""},""id1"":{""status"":""Unhealthy"",""description"":""desc1""}}",
  LogLevel.Warning,
  0
  },
  {
  CreateOptions(true, null),
  [HealthStatus.Healthy, (HealthStatus.Unhealthy, "some.tag")],
  1,
- "Process reporting unhealthy: Unhealthy. Health check entries are id0: {status: Healthy, description: desc0}, id1: {status: Unhealthy, description: desc1}",
+ "Process reporting unhealthy: Unhealthy. Health check entries are " +
+ @"{""id0"":{""status"":""Healthy"",""description"":""desc0""},""id1"":{""status"":""Unhealthy"",""description"":""desc1""}}",
  LogLevel.Warning,
  0
  },
@@ -74,7 +78,7 @@ public class TelemetryHealthCheckPublisherTests
  [HealthStatus.Healthy, (HealthStatus.Degraded, "some.tag"), HealthStatus.Unhealthy],
  1,
  "Process reporting unhealthy: Unhealthy. Health check entries are " +
- "id0: {status: Healthy, description: desc0}, id1: {status: Degraded, description: desc1}, id2: {status: Unhealthy, description: desc2}",
+ @"{""id0"":{""status"":""Healthy"",""description"":""desc0""},""id1"":{""status"":""Degraded"",""description"":""desc1""},""id2"":{""status"":""Unhealthy"",""description"":""desc2""}}",
  LogLevel.Warning,
  0
  },
@@ -91,7 +95,7 @@ public class TelemetryHealthCheckPublisherTests
  [HealthStatus.Healthy, (HealthStatus.Degraded, "some.tag"), HealthStatus.Unhealthy],
  1,
  "Process reporting unhealthy: Degraded. Health check entries are " +
- "id1: {status: Degraded, description: desc1}",
+ @"{""id1"":{""status"":""Degraded"",""description"":""desc1""}}",
  LogLevel.Warning,
  0.5
  },
@@ -100,7 +104,7 @@ public class TelemetryHealthCheckPublisherTests
  [(HealthStatus.Healthy, "some.tag"), (HealthStatus.Degraded, "some.tag"), (HealthStatus.Unhealthy, "some.other.tag"), (HealthStatus.Unhealthy, "some.tag")],
  1,
  "Process reporting unhealthy: Unhealthy. Health check entries are " +
- "id0: {status: Healthy, description: desc0}, id1: {status: Degraded, description: desc1}, id3: {status: Unhealthy, description: desc3}",
+ @"{""id0"":{""status"":""Healthy"",""description"":""desc0""},""id1"":{""status"":""Degraded"",""description"":""desc1""},""id3"":{""status"":""Unhealthy"",""description"":""desc3""}}",
  LogLevel.Warning,
  0
  }