Add HTTP Response Compression Support

schemas/dab.draft.schema.json

@@ -424,6 +424,19 @@
             }
           }
         },
+        "compression": {
+          "type": "object",
+          "description": "Configures HTTP response compression settings.",
+          "additionalProperties": false,
+          "properties": {
+            "level": {
+              "type": "string",
+              "enum": ["optimal", "fastest", "none"],
+              "default": "optimal",
+              "description": "Specifies the response compression level. 'optimal' provides best compression ratio, 'fastest' prioritizes speed, 'none' disables compression."
+            }
+          }
+        },
         "telemetry": {
           "type": "object",
           "description": "Telemetry configuration",

src/Cli.Tests/ConfigureOptionsTests.cs

@@ -540,6 +540,34 @@ public void TestUpdateTTLForCacheSettings(int updatedTtlValue)
             Assert.AreEqual(updatedTtlValue, runtimeConfig.Runtime.Cache.TtlSeconds);
         }
 
+        /// <summary>
+        /// Tests that running "dab configure --runtime.compression.level {value}" on a config with various values results
+        /// in runtime config update. Takes in updated value for compression.level and
+        /// validates whether the runtime config reflects those updated values.
+        [DataTestMethod]
+        [DataRow(CompressionLevel.Fastest, DisplayName = "Update Compression.Level to fastest.")]
+        [DataRow(CompressionLevel.Optimal, DisplayName = "Update Compression.Level to optimal.")]
+        [DataRow(CompressionLevel.None, DisplayName = "Update Compression.Level to none.")]
+        public void TestUpdateLevelForCompressionSettings(CompressionLevel updatedLevelValue)
+        {
+            // Arrange -> all the setup which includes creating options.
+            SetupFileSystemWithInitialConfig(INITIAL_CONFIG);
+
+            // Act: Attempts to update compression level value
+            ConfigureOptions options = new(
+                runtimeCompressionLevel: updatedLevelValue,
+                config: TEST_RUNTIME_CONFIG_FILE
+            );
+            bool isSuccess = TryConfigureSettings(options, _runtimeConfigLoader!, _fileSystem!);
+
+            // Assert: Validate the Level Value is updated
+            Assert.IsTrue(isSuccess);
+            string updatedConfig = _fileSystem!.File.ReadAllText(TEST_RUNTIME_CONFIG_FILE);
+            Assert.IsTrue(RuntimeConfigLoader.TryParseConfig(updatedConfig, out RuntimeConfig? runtimeConfig));
+            Assert.IsNotNull(runtimeConfig.Runtime?.Compression?.Level);
+            Assert.AreEqual(updatedLevelValue, runtimeConfig.Runtime.Compression.Level);
+        }
+
         /// <summary>
         /// Tests that running "dab configure --runtime.host.mode {value}" on a config with various values results
         /// in runtime config update. Takes in updated value for host.mode and 

src/Cli/Commands/ConfigureOptions.cs

@@ -47,6 +47,7 @@ public ConfigureOptions(
             bool? runtimeMcpDmlToolsExecuteEntityEnabled = null,
             bool? runtimeCacheEnabled = null,
             int? runtimeCacheTtl = null,
+            CompressionLevel? runtimeCompressionLevel = null,
             HostMode? runtimeHostMode = null,
             IEnumerable<string>? runtimeHostCorsOrigins = null,
             bool? runtimeHostCorsAllowCredentials = null,
@@ -103,6 +104,8 @@ public ConfigureOptions(
             // Cache
             RuntimeCacheEnabled = runtimeCacheEnabled;
             RuntimeCacheTTL = runtimeCacheTtl;
+            // Compression
+            RuntimeCompressionLevel = runtimeCompressionLevel;
             // Host
             RuntimeHostMode = runtimeHostMode;
             RuntimeHostCorsOrigins = runtimeHostCorsOrigins;
@@ -207,6 +210,9 @@ public ConfigureOptions(
         [Option("runtime.cache.ttl-seconds", Required = false, HelpText = "Customize the DAB cache's global default time to live in seconds. Default: 5 seconds (Integer).")]
         public int? RuntimeCacheTTL { get; }
 
+        [Option("runtime.compression.level", Required = false, HelpText = "Set the response compression level. Allowed values: optimal (default), fastest, none.")]
+        public CompressionLevel? RuntimeCompressionLevel { get; }
+
         [Option("runtime.host.mode", Required = false, HelpText = "Set the host running mode of DAB in Development or Production. Default: Development.")]
         public HostMode? RuntimeHostMode { get; }
 

src/Cli/ConfigGenerator.cs

@@ -828,6 +828,21 @@ private static bool TryUpdateConfiguredRuntimeOptions(
                 }
             }
 
+            // Compression: Level
+            if (options.RuntimeCompressionLevel != null)
+            {
+                CompressionOptions updatedCompressionOptions = runtimeConfig?.Runtime?.Compression ?? new();
+                bool status = TryUpdateConfiguredCompressionValues(options, ref updatedCompressionOptions);
+                if (status)
+                {
+                    runtimeConfig = runtimeConfig! with { Runtime = runtimeConfig.Runtime! with { Compression = updatedCompressionOptions } };
+                }
+                else
+                {
+                    return false;
+                }
+            }
+
             // Host: Mode, Cors.Origins, Cors.AllowCredentials, Authentication.Provider, Authentication.Jwt.Audience, Authentication.Jwt.Issuer
             if (options.RuntimeHostMode != null ||
                 options.RuntimeHostCorsOrigins != null ||
@@ -1197,6 +1212,37 @@ private static bool TryUpdateConfiguredCacheValues(
             }
         }
 
+        /// <summary>
+        /// Attempts to update the Config parameters in the Compression runtime settings based on the provided value.
+        /// Validates user-provided parameters and then returns true if the updated Compression options
+        /// need to be overwritten on the existing config parameters.
+        /// </summary>
+        /// <param name="options">options.</param>
+        /// <param name="updatedCompressionOptions">updatedCompressionOptions.</param>
+        /// <returns>True if the value needs to be updated in the runtime config, else false</returns>
+        private static bool TryUpdateConfiguredCompressionValues(
+            ConfigureOptions options,
+            ref CompressionOptions updatedCompressionOptions)
+        {
+            try
+            {
+                // Runtime.Compression.Level
+                CompressionLevel? updatedValue = options?.RuntimeCompressionLevel;
+                if (updatedValue != null)
+                {
+                    updatedCompressionOptions = updatedCompressionOptions with { Level = updatedValue.Value, UserProvidedLevel = true };
+                    _logger.LogInformation("Updated RuntimeConfig with Runtime.Compression.Level as '{updatedValue}'", updatedValue);
+                }
+
+                return true;
+            }
+            catch (Exception ex)
+            {
+                _logger.LogError("Failed to configure RuntimeConfig.Compression with exception message: {exceptionMessage}.", ex.Message);
+                return false;
+            }
+        }
+
         /// <summary>
         /// Attempts to update the Config parameters in the Host runtime settings based on the provided value.
         /// Validates that any user-provided parameter value is valid and then returns true if the updated Host options

src/Config/Converters/CompressionOptionsConverterFactory.cs

@@ -0,0 +1,104 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+using System.Text.Json;
+using System.Text.Json.Serialization;
+using Azure.DataApiBuilder.Config.ObjectModel;
+
+namespace Azure.DataApiBuilder.Config.Converters;
+
+/// <summary>
+/// Defines how DAB reads and writes the compression options (JSON).
+/// </summary>
+internal class CompressionOptionsConverterFactory : JsonConverterFactory
+{
+    /// <inheritdoc/>
+    public override bool CanConvert(Type typeToConvert)
+    {
+        return typeToConvert.IsAssignableTo(typeof(CompressionOptions));
+    }
+
+    /// <inheritdoc/>
+    public override JsonConverter? CreateConverter(Type typeToConvert, JsonSerializerOptions options)
+    {
+        return new CompressionOptionsConverter();
+    }
+
+    private class CompressionOptionsConverter : JsonConverter<CompressionOptions>
+    {
+        /// <summary>
+        /// Defines how DAB reads the compression options and defines which values are
+        /// used to instantiate CompressionOptions.
+        /// </summary>
+        public override CompressionOptions? Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
+        {
+            if (reader.TokenType == JsonTokenType.Null)
+            {
+                return null;
+            }
+
+            if (reader.TokenType != JsonTokenType.StartObject)
+            {
+                throw new JsonException("Expected start of object.");
+            }
+
+            CompressionLevel level = CompressionOptions.DEFAULT_LEVEL;
+            bool userProvidedLevel = false;
+
+            while (reader.Read())
+            {
+                if (reader.TokenType == JsonTokenType.EndObject)
+                {
+                    break;
+                }
+
+                if (reader.TokenType == JsonTokenType.PropertyName)
+                {
+                    string? propertyName = reader.GetString();
+                    reader.Read();
+
+                    if (string.Equals(propertyName, "level", StringComparison.OrdinalIgnoreCase))
+                    {
+                        string? levelStr = reader.GetString();
+                        if (levelStr is not null)
+                        {
+                            if (Enum.TryParse<CompressionLevel>(levelStr, ignoreCase: true, out CompressionLevel parsedLevel))
+                            {
+                                level = parsedLevel;
+                                userProvidedLevel = true;
+                            }
+                            else
+                            {
+                                throw new JsonException($"Invalid compression level: '{levelStr}'. Valid values are: optimal, fastest, none.");
+                            }
+                        }
+                    }
+                    else
+                    {
+                        // Skip unknown properties and their values (including objects/arrays)
+                        reader.Skip();
+                    }
+                }
+            }
+
+            return new CompressionOptions(level) with { UserProvidedLevel = userProvidedLevel };
+        }
+
+        /// <summary>
+        /// When writing the CompressionOptions back to a JSON file, only write the level
+        /// property and value when it was provided by the user.
+        /// </summary>
+        public override void Write(Utf8JsonWriter writer, CompressionOptions value, JsonSerializerOptions options)
+        {
+            writer.WriteStartObject();
+
+            if (value is not null && value.UserProvidedLevel)
+            {
+                writer.WritePropertyName("level");
+                writer.WriteStringValue(value.Level.ToString().ToLowerInvariant());
+            }
+
+            writer.WriteEndObject();
+        }
+    }
+}

src/Config/ObjectModel/CompressionLevel.cs

@@ -0,0 +1,28 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+using System.Text.Json.Serialization;
+
+namespace Azure.DataApiBuilder.Config.ObjectModel;
+
+/// <summary>
+/// Specifies the compression level for HTTP response compression.
+/// </summary>
+[JsonConverter(typeof(JsonStringEnumConverter))]
+public enum CompressionLevel
+{
+    /// <summary>
+    /// Provides the best compression ratio at the cost of speed.
+    /// </summary>
+    Optimal,
+
+    /// <summary>
+    /// Provides the fastest compression at the cost of compression ratio.
+    /// </summary>
+    Fastest,
+
+    /// <summary>
+    /// Disables compression.
+    /// </summary>
+    None
+}

src/Config/ObjectModel/CompressionOptions.cs

@@ -0,0 +1,46 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+using System.Text.Json.Serialization;
+
+namespace Azure.DataApiBuilder.Config.ObjectModel;
+
+/// <summary>
+/// Configuration options for HTTP response compression.
+/// </summary>
+public record CompressionOptions
+{
+    /// <summary>
+    /// Default compression level is Optimal.
+    /// </summary>
+    public const CompressionLevel DEFAULT_LEVEL = CompressionLevel.Optimal;
+
+    /// <summary>
+    /// The compression level to use for HTTP response compression.
+    /// </summary>
+    [JsonPropertyName("level")]
+    public CompressionLevel Level { get; init; } = DEFAULT_LEVEL;
+
+    /// <summary>
+    /// Flag which informs CLI and JSON serializer whether to write Level
+    /// property and value to the runtime config file.
+    /// </summary>
+    [JsonIgnore(Condition = JsonIgnoreCondition.Always)]
+    public bool UserProvidedLevel { get; init; } = false;
+
+    [JsonConstructor]
+    public CompressionOptions(CompressionLevel Level = DEFAULT_LEVEL)
+    {
+        this.Level = Level;
+        this.UserProvidedLevel = true;
+    }
+
+    /// <summary>
+    /// Default parameterless constructor for cases where no compression level is specified.
+    /// </summary>
+    public CompressionOptions()
+    {
+        this.Level = DEFAULT_LEVEL;
+        this.UserProvidedLevel = false;
+    }
+}

src/Config/ObjectModel/RuntimeOptions.cs

@@ -17,6 +17,7 @@ public record RuntimeOptions
     public RuntimeCacheOptions? Cache { get; init; }
     public PaginationOptions? Pagination { get; init; }
     public RuntimeHealthCheckConfig? Health { get; init; }
+    public CompressionOptions? Compression { get; init; }
 
     [JsonConstructor]
     public RuntimeOptions(
@@ -28,7 +29,8 @@ public RuntimeOptions(
         TelemetryOptions? Telemetry = null,
         RuntimeCacheOptions? Cache = null,
         PaginationOptions? Pagination = null,
-        RuntimeHealthCheckConfig? Health = null)
+        RuntimeHealthCheckConfig? Health = null,
+        CompressionOptions? Compression = null)
     {
         this.Rest = Rest;
         this.GraphQL = GraphQL;
@@ -39,6 +41,7 @@ public RuntimeOptions(
         this.Cache = Cache;
         this.Pagination = Pagination;
         this.Health = Health;
+        this.Compression = Compression;
     }
 
     /// <summary>

src/Config/RuntimeConfigLoader.cs

@@ -316,6 +316,7 @@ public static JsonSerializerOptions GetSerializationOptions(
         options.Converters.Add(new EntityCacheOptionsConverterFactory(replacementSettings));
         options.Converters.Add(new RuntimeCacheOptionsConverterFactory());
         options.Converters.Add(new RuntimeCacheLevel2OptionsConverterFactory());
+        options.Converters.Add(new CompressionOptionsConverterFactory());
         options.Converters.Add(new MultipleCreateOptionsConverter());
         options.Converters.Add(new MultipleMutationOptionsConverter(options));
         options.Converters.Add(new DataSourceConverterFactory(replacementSettings));