Add ClickHouse HealthCheck support

src/HealthChecks.ClickHouse/ClickHouseHealthCheck.cs

@@ -1,3 +1,4 @@
+using ClickHouse.Client.ADO;
 using Microsoft.Extensions.Diagnostics.HealthChecks;
 
 namespace HealthChecks.ClickHouse;
@@ -7,29 +8,30 @@ namespace HealthChecks.ClickHouse;
 /// </summary>
 public class ClickHouseHealthCheck : IHealthCheck
 {
-    private readonly ClickHouseHealthCheckOptions _options;
+    internal const string HEALTH_QUERY = "SELECT 1;";
 
-    public ClickHouseHealthCheck(ClickHouseHealthCheckOptions options)
+    private readonly ClickHouseConnection _connection;
+    private readonly string _command;
+
+    public ClickHouseHealthCheck(ClickHouseConnection connection, string command)
     {
-        Guard.ThrowIfNull(options.CommandText, true);
-        _options = options;
+        _connection = connection;
+        _command = command ?? HEALTH_QUERY;
     }
 
     /// <inheritdoc />
     public async Task<HealthCheckResult> CheckHealthAsync(HealthCheckContext context, CancellationToken cancellationToken = default)
     {
         try
         {
-            await using var connection = _options.ConnectionFactory();
-            await connection.OpenAsync(cancellationToken).ConfigureAwait(false);
+            await _connection.OpenAsync(cancellationToken).ConfigureAwait(false);
+
+            using var command = _connection.CreateCommand();
+            command.CommandText = _command;
 
-            using var command = connection.CreateCommand();
-            command.CommandText = _options.CommandText;
-            var result = await command.ExecuteScalarAsync(cancellationToken).ConfigureAwait(false);
+            await command.ExecuteScalarAsync(cancellationToken).ConfigureAwait(false);
 
-            return _options.HealthCheckResultBuilder == null
-                ? HealthCheckResult.Healthy()
-                : _options.HealthCheckResultBuilder(result);
+            return HealthCheckResult.Healthy();
         }
         catch (Exception ex)
         {

src/HealthChecks.ClickHouse/DependencyInjection/ClickHouseHealthCheckBuilderExtensions.cs

@@ -10,7 +10,6 @@ namespace Microsoft.Extensions.DependencyInjection;
 public static class ClickHouseHealthCheckBuilderExtensions
 {
     private const string NAME = "ClickHouse";
-    internal const string HEALTH_QUERY = "SELECT 1;";
 
     /// <summary>
     /// Add a health check for ClickHouse databases.
@@ -29,54 +28,18 @@ public static class ClickHouseHealthCheckBuilderExtensions
     public static IHealthChecksBuilder AddClickHouse(
         this IHealthChecksBuilder builder,
         Func<IServiceProvider, ClickHouseConnection> connectionFactory,
-        string healthQuery = HEALTH_QUERY,
+        string healthQuery = ClickHouseHealthCheck.HEALTH_QUERY,
         string? name = default,
         HealthStatus? failureStatus = default,
         IEnumerable<string>? tags = default,
         TimeSpan? timeout = default)
     {
-        if (connectionFactory == null)
-        {
-            throw new ArgumentNullException(nameof(connectionFactory));
-        }
+        Guard.ThrowIfNull(connectionFactory);
+        Guard.ThrowIfNull(healthQuery);
 
         return builder.Add(new HealthCheckRegistration(
             name ?? NAME,
-            sp => new ClickHouseHealthCheck(new ClickHouseHealthCheckOptions(() => Guard.ThrowIfNull(connectionFactory.Invoke(sp), paramName: nameof(connectionFactory)))
-            {
-                CommandText = healthQuery
-            }),
-            failureStatus,
-            tags,
-            timeout));
-    }
-
-    /// <summary>
-    /// Add a health check for ClickHouse databases.
-    /// </summary>
-    /// <param name="builder">The <see cref="IHealthChecksBuilder"/>.</param>
-    /// <param name="options">Options for health check.</param>
-    /// <param name="name">The health check name. Optional. If <c>null</c> the type name 'ClickHouse' will be used for the name.</param>
-    /// <param name="failureStatus">
-    /// The <see cref="HealthStatus"/> that should be reported when the health check fails. Optional. If <c>null</c> then
-    /// the default status of <see cref="HealthStatus.Unhealthy"/> will be reported.
-    /// </param>
-    /// <param name="tags">A list of tags that can be used to filter sets of health checks. Optional.</param>
-    /// <param name="timeout">An optional <see cref="TimeSpan"/> representing the timeout of the check.</param>
-    /// <returns>The specified <paramref name="builder"/>.</returns>
-    public static IHealthChecksBuilder AddClickHouse(
-        this IHealthChecksBuilder builder,
-        ClickHouseHealthCheckOptions options,
-        string? name = default,
-        HealthStatus? failureStatus = default,
-        IEnumerable<string>? tags = default,
-        TimeSpan? timeout = default)
-    {
-        Guard.ThrowIfNull(options);
-
-        return builder.Add(new HealthCheckRegistration(
-            name ?? NAME,
-            _ => new ClickHouseHealthCheck(options),
+            sp => new ClickHouseHealthCheck(connectionFactory(sp), healthQuery),
             failureStatus,
             tags,
             timeout));

test/HealthChecks.ClickHouse.Tests/DependencyInjection/RegistrationTests.cs

@@ -17,7 +17,7 @@ public void add_health_check_when_properly_configured()
         var registration = options.Value.Registrations.First();
         var check = registration.Factory(serviceProvider);
 
-        registration.Name.ShouldBe("clickhouse");
+        registration.Name.ShouldBe("ClickHouse");
         check.ShouldBeOfType<ClickHouseHealthCheck>();
     }
 
@@ -63,7 +63,7 @@ public void add_health_check_with_connection_string_factory_when_properly_config
     }
 
     [Fact]
-    public void factory_is_called_only_once()
+    public void factory_is_called_everytime_healthcheck_is_created()
     {
         ServiceCollection services = new();
         int factoryCalls = 0;
@@ -85,6 +85,7 @@ public void factory_is_called_only_once()
             _ = registration.Factory(serviceProvider);
         }
 
-        factoryCalls.ShouldBe(1);
+        // ClickHouseConnection is not thread safe, so we assume that that we get a new instance every time
+        factoryCalls.ShouldBe(10);
     }
 }

test/HealthChecks.ClickHouse.Tests/HealthChecks.ClickHouse.approved.txt

@@ -2,24 +2,14 @@ namespace HealthChecks.ClickHouse
 {
     public class ClickHouseHealthCheck : Microsoft.Extensions.Diagnostics.HealthChecks.IHealthCheck
     {
-        public ClickHouseHealthCheck(HealthChecks.ClickHouse.ClickHouseHealthCheckOptions options) { }
+        public ClickHouseHealthCheck(ClickHouse.Client.ADO.ClickHouseConnection connection, string command) { }
         public System.Threading.Tasks.Task<Microsoft.Extensions.Diagnostics.HealthChecks.HealthCheckResult> CheckHealthAsync(Microsoft.Extensions.Diagnostics.HealthChecks.HealthCheckContext context, System.Threading.CancellationToken cancellationToken = default) { }
     }
-    public class ClickHouseHealthCheckOptions
-    {
-        public ClickHouseHealthCheckOptions(string connectionString) { }
-        public string CommandText { get; set; }
-        public System.Action<ClickHouse.ClickHouseConnection>? Configure { get; set; }
-        public string? ConnectionString { get; }
-        public System.Func<object?, Microsoft.Extensions.Diagnostics.HealthChecks.HealthCheckResult>? HealthCheckResultBuilder { get; set; }
-    }
 }
 namespace Microsoft.Extensions.DependencyInjection
 {
     public static class ClickHouseHealthCheckBuilderExtensions
     {
-        public static Microsoft.Extensions.DependencyInjection.IHealthChecksBuilder AddClickHouse(this Microsoft.Extensions.DependencyInjection.IHealthChecksBuilder builder, HealthChecks.ClickHouse.ClickHouseHealthCheckOptions options, string? name = null, Microsoft.Extensions.Diagnostics.HealthChecks.HealthStatus? failureStatus = default, System.Collections.Generic.IEnumerable<string>? tags = null, System.TimeSpan? timeout = default) { }
-        public static Microsoft.Extensions.DependencyInjection.IHealthChecksBuilder AddClickHouse(this Microsoft.Extensions.DependencyInjection.IHealthChecksBuilder builder, System.Func<System.IServiceProvider, string> connectionStringFactory, string healthQuery = "SELECT 1;", System.Action<ClickHouse.ClickHouseConnection>? configure = null, string? name = null, Microsoft.Extensions.Diagnostics.HealthChecks.HealthStatus? failureStatus = default, System.Collections.Generic.IEnumerable<string>? tags = null, System.TimeSpan? timeout = default) { }
-        public static Microsoft.Extensions.DependencyInjection.IHealthChecksBuilder AddClickHouse(this Microsoft.Extensions.DependencyInjection.IHealthChecksBuilder builder, string connectionString, string healthQuery = "SELECT 1;", System.Action<ClickHouse.ClickHouseConnection>? configure = null, string? name = null, Microsoft.Extensions.Diagnostics.HealthChecks.HealthStatus? failureStatus = default, System.Collections.Generic.IEnumerable<string>? tags = null, System.TimeSpan? timeout = default) { }
+        public static Microsoft.Extensions.DependencyInjection.IHealthChecksBuilder AddClickHouse(this Microsoft.Extensions.DependencyInjection.IHealthChecksBuilder builder, System.Func<System.IServiceProvider, ClickHouse.Client.ADO.ClickHouseConnection> connectionFactory, string healthQuery = "SELECT 1;", string? name = null, Microsoft.Extensions.Diagnostics.HealthChecks.HealthStatus? failureStatus = default, System.Collections.Generic.IEnumerable<string>? tags = null, System.TimeSpan? timeout = default) { }
     }
 }