Improve missing KMS error message (confluentinc#6) (confluentinc#2279)

* Improve missing KMS error message

Also enhance examples, some minor cleanup

* Fix tests

Author: rayokota

examples/AvroGenericEncryption/Program.cs

@@ -48,6 +48,7 @@ static async Task Main(string[] args)
             AzureKmsDriver.Register();
             GcpKmsDriver.Register();
             HcVaultKmsDriver.Register();
+            LocalKmsDriver.Register();
             FieldEncryptionExecutor.Register();
 
             string bootstrapServers = args[0];
@@ -79,7 +80,10 @@ static async Task Main(string[] args)
                 // optional Avro serializer properties:
                 BufferBytes = 100
             };
-            
+            // KMS properties can be passed as follows
+            // avroSerializerConfig.Set("rules.secret.access.key", "xxx");
+            // avroSerializerConfig.Set("rules.access.key.id", "xxx");
+
             RuleSet ruleSet = new RuleSet(new List<Rule>(),
                 new List<Rule>
                 {

examples/AvroSpecificEncryption/Program.cs

@@ -45,6 +45,7 @@ static void Main(string[] args)
             AzureKmsDriver.Register();
             GcpKmsDriver.Register();
             HcVaultKmsDriver.Register();
+            LocalKmsDriver.Register();
             FieldEncryptionExecutor.Register();
 
             string bootstrapServers = args[0];
@@ -82,7 +83,10 @@ static void Main(string[] args)
                 // optional Avro serializer properties:
                 BufferBytes = 100
             };
-            
+            // KMS properties can be passed as follows
+            // avroSerializerConfig.Set("rules.secret.access.key", "xxx");
+            // avroSerializerConfig.Set("rules.access.key.id", "xxx");
+
             RuleSet ruleSet = new RuleSet(new List<Rule>(),
                 new List<Rule>
                 {

examples/JsonEncryption/Program.cs

@@ -82,6 +82,7 @@ static async Task Main(string[] args)
             AzureKmsDriver.Register();
             GcpKmsDriver.Register();
             HcVaultKmsDriver.Register();
+            LocalKmsDriver.Register();
             FieldEncryptionExecutor.Register();
 
             string bootstrapServers = args[0];
@@ -135,6 +136,9 @@ static async Task Main(string[] args)
                 UseLatestVersion = true,
                 BufferBytes = 100
             };
+            // KMS properties can be passed as follows
+            // jsonSerializerConfig.Set("rules.secret.access.key", "xxx");
+            // jsonSerializerConfig.Set("rules.access.key.id", "xxx");
 
             RuleSet ruleSet = new RuleSet(new List<Rule>(),
                 new List<Rule>

examples/ProtobufEncryption/Program.cs

@@ -50,6 +50,7 @@ static async Task Main(string[] args)
             AzureKmsDriver.Register();
             GcpKmsDriver.Register();
             HcVaultKmsDriver.Register();
+            LocalKmsDriver.Register();
             FieldEncryptionExecutor.Register();
 
             string bootstrapServers = args[0];
@@ -96,7 +97,10 @@ message User {
                 // optional Avro serializer properties:
                 BufferBytes = 100
             };
-            
+            // KMS properties can be passed as follows
+            // protobufSerializerConfig.Set("rules.secret.access.key", "xxx");
+            // protobufSerializerConfig.Set("rules.access.key.id", "xxx");
+
             RuleSet ruleSet = new RuleSet(new List<Rule>(),
                 new List<Rule>
                 {

src/Confluent.SchemaRegistry.Encryption/KmsRegistry.cs

@@ -14,6 +14,7 @@
 //
 // Refer to LICENSE for more information.
 
+using System;
 using System.Collections.Generic;
 using System.Threading;
 
@@ -61,7 +62,7 @@ public static IKmsDriver GetKmsDriver(string keyUrl)
                 kmsDriversMutex.Release();
             }
 
-            return null;
+            throw new ArgumentException("No KMS driver found for key URL: " + keyUrl); ;
         }
 
         public static void RegisterKmsClient(IKmsClient kmsClient)

src/Confluent.SchemaRegistry/Rest/DataContracts/Schema.cs

@@ -30,21 +30,18 @@ public class Schema : IComparable<Schema>, IEquatable<Schema>
         #region API backwards-compatibility hack
 
         /// <summary>
-        ///     DEPRECATED. The subject the schema is registered against.
+        ///     The subject the schema is registered against.
         /// </summary>
-        [Obsolete("Included to maintain API backwards compatibility only. Use RegisteredSchema instead. This property will be removed in a future version of the library.")]
         public virtual string Subject { get; set; }
 
         /// <summary>
-        ///     DEPRECATED. The schema version.
+        ///     The schema version.
         /// </summary>
-        [Obsolete("Included to maintain API backwards compatibility only. Use RegisteredSchema instead. This property will be removed in a future version of the library.")]
         public virtual int Version { get; set; }
 
         /// <summary>
-        ///     DEPRECATED. Unique identifier of the schema.
+        ///     Unique identifier of the schema.
         /// </summary>
-        [Obsolete("Included to maintain API backwards compatibility only. Use RegisteredSchema instead. This property will be removed in a future version of the library.")]
         public virtual int Id { get; set; }
 
         /// <summary>