SendGrid ServiceProvider Overload

src/HealthChecks.SendGrid/DependencyInjection/SendGridHealthCheckExtensions.cs

@@ -31,13 +31,41 @@ public static IHealthChecksBuilder AddSendGrid(
         IEnumerable<string>? tags = default,
         TimeSpan? timeout = default)
     {
-        var registrationName = name ?? NAME;
+        return builder.AddSendGrid(_ => apiKey, name, failureStatus, tags, timeout);
+    }
+
+    /// <summary>
+    /// Add a health check for SendGrid.
+    /// </summary>
+    /// <param name="builder">The <see cref="IHealthChecksBuilder"/>.</param>
+    /// <param name="apiKeyFactory">Factory to resolve the API key.</param>
+    /// <param name="name">The health check name. Optional. If <c>null</c> the type name 'sendgrid' 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 AddSendGrid(
+        this IHealthChecksBuilder builder,
+        Func<IServiceProvider, string> apiKeyFactory,
+        string? name = default,
+        HealthStatus? failureStatus = default,
+        IEnumerable<string>? tags = default,
+        TimeSpan? timeout = default)
+    {
+        string registrationName = name ?? NAME;
 
         builder.Services.AddHttpClient(registrationName);
 
         return builder.Add(new HealthCheckRegistration(
             registrationName,
-            sp => new SendGridHealthCheck(apiKey, sp.GetRequiredService<IHttpClientFactory>()),
+            sp =>
+            {
+                string apiKey = apiKeyFactory(sp);
+                return new SendGridHealthCheck(apiKey, sp.GetRequiredService<IHttpClientFactory>());
+            },
             failureStatus,
             tags,
             timeout));

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

@@ -19,6 +19,30 @@ public void add_health_check_when_properly_configured()
         check.ShouldBeOfType<SendGridHealthCheck>();
     }
 
+    private class SendGridOptions
+    {
+        public string ApiKey { get; set; } = default!;
+    }
+
+    [Fact]
+    public void add_health_check_from_DI_when_properly_configured()
+    {
+        var services = new ServiceCollection();
+
+        services.AddOptions<SendGridOptions>().Configure(options => options.ApiKey = "my_api_key");
+        services.AddHealthChecks()
+            .AddSendGrid(sp => sp.GetRequiredService<IOptions<SendGridOptions>>().Value.ApiKey);
+
+        using var serviceProvider = services.BuildServiceProvider();
+        var options = serviceProvider.GetRequiredService<IOptions<HealthCheckServiceOptions>>();
+
+        var registration = options.Value.Registrations.First();
+        var check = registration.Factory(serviceProvider);
+
+        registration.Name.ShouldBe("sendgrid");
+        check.ShouldBeOfType<SendGridHealthCheck>();
+    }
+
     [Fact]
     public void add_named_health_check_when_properly_configured()
     {