Add a new config GetDouble function. Fix LingerMs (#1083)

* Add a new config GetDouble function.  Replace GetEnum function with GetDouble on LingerMs.

* fixed whitespace

* Adding double as type in ConfigGen project so that Config_Gen can be created correctly

* new Config_gen.cs + added LingerMs to test

Author: lorienpatt

src/ConfigGen/Program.cs

@@ -352,6 +352,9 @@ static string createProperties(IEnumerable<PropertySpecification> props)
                     case "bool":
                         codeText += $"GetBool(\"{prop.Name}\")";
                         break;
+                    case "double":
+                        codeText += $"GetDouble(\"{prop.Name}\")";
+                        break;
                     default:
                         codeText += $"({nullableType})GetEnum(typeof({type}), \"{prop.Name}\")";
                         break;

src/Confluent.Kafka/Config.cs

@@ -125,6 +125,22 @@ public string Get(string key)
             return bool.Parse(result);
         }
 
+        /// <summary>
+        ///     Gets a configuration property double? value given a key.
+        /// </summary>
+        /// <param name="key">
+        ///     The configuration property to get.
+        /// </param>
+        /// <returns>
+        ///     The configuration property value.
+        /// </returns>
+        protected double? GetDouble(string key)
+        {
+            var result = Get(key);
+            if (result == null) { return null; }
+            return double.Parse(result);
+        }
+
         /// <summary>
         ///     Gets a configuration property enum value given a key.
         /// </summary>

src/Confluent.Kafka/Config_gen.cs

@@ -1,4 +1,4 @@
-// *** Auto-generated from librdkafka 7632802d315b1a10f27e957400a3ec74f12ffbe8 *** - do not modify manually.
+// *** Auto-generated from librdkafka v1.2.1 *** - do not modify manually.
 //
 // Copyright 2018 Confluent Inc.
 //
@@ -943,7 +943,7 @@ public ProducerConfig(IDictionary<string, string> config) : base(config) { }
         ///     default: 0.5
         ///     importance: high
         /// </summary>
-        public double? LingerMs { get { return (double?)GetEnum(typeof(double), "linger.ms"); } set { this.SetObject("linger.ms", value); } }
+        public double? LingerMs { get { return GetDouble("linger.ms"); } set { this.SetObject("linger.ms", value); } }
 
         /// <summary>
         ///     How many times to retry sending a failing Message. **Note:** retrying may cause reordering unless `enable.idempotence` is set to true.
@@ -1174,7 +1174,7 @@ public ConsumerConfig(IDictionary<string, string> config) : base(config) { }
         /// <summary>
         ///     Controls how to read messages written transactionally: `read_committed` - only return transactional messages which have been committed. `read_uncommitted` - return all messages, even transactional messages which have been aborted.
         ///
-        ///     default: read_uncommitted
+        ///     default: read_committed
         ///     importance: high
         /// </summary>
         public IsolationLevel? IsolationLevel { get { return (IsolationLevel?)GetEnum(typeof(IsolationLevel), "isolation.level"); } set { this.SetObject("isolation.level", value); } }

test/Confluent.Kafka.IntegrationTests/Tests/Producer_Produce.cs

@@ -36,7 +36,8 @@ public void Producer_Produce(string bootstrapServers)
             var producerConfig = new ProducerConfig
             { 
                 BootstrapServers = bootstrapServers,
-                EnableIdempotence = true
+                EnableIdempotence = true,
+                LingerMs = 1.5
             };