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Fix null reference error when using avro deserialization #594

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Merged
aloiva merged 6 commits into from
Sep 26, 2025
Merged

Fix null reference error when using avro deserialization #594

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3a0c60f
add e2e test
Sep 25, 2025
fd32c5e
remove key schema from local registry
Sep 25, 2025
73eaad2
use two local schema registry for value and key
Sep 25, 2025
aeda47a
Merge branch 'dev' into prgaddam/fixavronullerror
aloiva Sep 25, 2025
dc78d68
fix comments
Sep 25, 2025
e8e0131
remove unused test
Sep 25, 2025
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43 changes: 11 additions & 32 deletions src/Microsoft.Azure.WebJobs.Extensions.Kafka/Serialization/LocalSchemaRegistry.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -12,39 +12,33 @@ namespace Microsoft.Azure.WebJobs.Extensions.Kafka
/// </summary>
public class LocalSchemaRegistry : ISchemaRegistryClient
{
private readonly string valueSchema;
private readonly string keySchema;
private const int ValueId = 1;
private const int KeyId = 2;
private string valueSubject;
private string keySubject;
private readonly string schema;
private List<string> subjects = new List<string>();

public LocalSchemaRegistry(string valueSchema, string keySchema = null)
public LocalSchemaRegistry(string schema)
{
this.valueSchema = valueSchema;
this.keySchema = keySchema;
this.schema = schema;
}

public int MaxCachedSchemas
{
get
get
{
return 2;
return 1;
}
}

public string ConstructKeySubjectName(string topic, string recordType = null) => keySubject = $"{topic}-key";
public string ConstructKeySubjectName(string topic, string recordType = null) => $"{topic}-key";

public string ConstructValueSubjectName(string topic, string recordType = null) => valueSubject = $"{topic}-value";
public string ConstructValueSubjectName(string topic, string recordType = null) => topic;

public void Dispose()
{
}

public Task<List<string>> GetAllSubjectsAsync()
{
return Task.FromResult(subjects);
return Task.FromResult(this.subjects);
}

public Task<Compatibility> GetCompatibilityAsync(string subject = null)
Expand All @@ -64,28 +58,13 @@ public Task<RegisteredSchema> GetRegisteredSchemaAsync(string subject, int versi

public Task<string> GetSchemaAsync(string subject, int version)
{
if (subject == keySubject)
{
return Task.FromResult(keySchema);
}
else if (subject == valueSubject)
{
return Task.FromResult(valueSchema);
}
return Task.FromResult<string>(null);
return Task.FromResult(this.schema);
}

public Task<Schema> GetSchemaAsync(int id, string format = null)
{
if (id == KeyId)
{
return Task.FromResult(new Schema(keySchema, SchemaType.Avro));
}
else if (id == ValueId)
{
return Task.FromResult(new Schema(valueSchema, SchemaType.Avro));
}
return Task.FromResult<Schema>(null);
var schema = new Schema(this.schema, SchemaType.Avro);
return Task.FromResult(schema);
}

public Task<int> GetSchemaIdAsync(string subject, string schema)
Expand Down
37 changes: 19 additions & 18 deletions src/Microsoft.Azure.WebJobs.Extensions.Kafka/Serialization/SerializationHelper.cs
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Expand Up @@ -60,17 +60,16 @@ internal static (object, object) ResolveDeserializers(GetKeyAndValueTypesResult
// check for avro deserialization
if (specifiedValueAvroSchema != null || specifiedKeyAvroSchema != null)
{
// creates local schema registry if no schema registry url is specified
var schemaRegistry = CreateSchemaRegistry(specifiedValueAvroSchema, specifiedKeyAvroSchema, schemaRegistryUrl, schemaRegistryUsername, schemaRegistryPassword);

// if value avro schema exists and value type is generic record, create avro deserializer
if (!string.IsNullOrWhiteSpace(specifiedValueAvroSchema))
{
// creates local schema registry to store only value schema since no schema registry url is specified
var valueSchemaRegistry = CreateSchemaRegistry(specifiedValueAvroSchema, schemaRegistryUrl, schemaRegistryUsername, schemaRegistryPassword);
if (isValueGenericRecord || isValueSpecificRecord)
{
var methodInfo = typeof(SerializationHelper).GetMethod(nameof(CreateAvroValueDeserializer), BindingFlags.Static | BindingFlags.NonPublic);
var genericMethod = methodInfo.MakeGenericMethod(valueType);
valueDeserializer = genericMethod.Invoke(null, new object[] { schemaRegistry });
valueDeserializer = genericMethod.Invoke(null, new object[] { valueSchemaRegistry });
}
else
{
Expand All @@ -83,9 +82,11 @@ internal static (object, object) ResolveDeserializers(GetKeyAndValueTypesResult
{
if (isKeyGenericRecord || isKeySpecificRecord)
{
// creates local schema registry to store only value schema since no schema registry url is specified
var keySchemaRegistry = CreateSchemaRegistry(specifiedKeyAvroSchema, schemaRegistryUrl, schemaRegistryUsername, schemaRegistryPassword);
var methodInfo = typeof(SerializationHelper).GetMethod(nameof(CreateAvroKeyDeserializer), BindingFlags.Static | BindingFlags.NonPublic);
var genericMethod = methodInfo.MakeGenericMethod(keyType);
keyDeserializer = genericMethod.Invoke(null, new object[] { schemaRegistry });
keyDeserializer = genericMethod.Invoke(null, new object[] { keySchemaRegistry });
}
else
{
Expand All @@ -102,7 +103,7 @@ internal static (object, object) ResolveSchemaRegistryDeserializers(Type valueTy
object valueDeserializer = null;
object keyDeserializer = null;

var schemaRegistry = CreateSchemaRegistry(null, null, schemaRegistryUrl, schemaRegistryUsername, schemaRegistryPassword);
var schemaRegistry = CreateSchemaRegistry(null, schemaRegistryUrl, schemaRegistryUsername, schemaRegistryPassword);

if (typeof(GenericRecord).IsAssignableFrom(valueType))
{
Expand Down Expand Up @@ -172,19 +173,21 @@ internal static (object, object) ResolveSerializers(Type valueType, Type keyType
// check for avro serialization
if (specifiedValueAvroSchema != null || specifiedKeyAvroSchema != null)
{
// create schema registry client
var schemaRegistry = CreateSchemaRegistry(specifiedValueAvroSchema, specifiedKeyAvroSchema, schemaRegistryUrl, schemaRegistryUsername, schemaRegistryPassword);
object serializer = null;

// create serializers for avro - generic or specific records
if (isValueGenericRecord || isValueSpecificRecord)
{
serializer = Activator.CreateInstance(typeof(AvroSerializer<>).MakeGenericType(valueType), schemaRegistry, null /* config */);
// create schema registry client only for value schema
var valueSchemaRegistry = CreateSchemaRegistry(specifiedValueAvroSchema, schemaRegistryUrl, schemaRegistryUsername, schemaRegistryPassword);
serializer = Activator.CreateInstance(typeof(AvroSerializer<>).MakeGenericType(valueType), valueSchemaRegistry, null /* config */);
valueSerializer = typeof(SyncOverAsyncSerializerExtensionMethods).GetMethod("AsSyncOverAsync").MakeGenericMethod(valueType).Invoke(null, new object[] { serializer });
}
if (isKeyGenericRecord || isKeySpecificRecord)
{
serializer = Activator.CreateInstance(typeof(AvroSerializer<>).MakeGenericType(keyType), schemaRegistry, null /* config */);
// create schema registry client only for key schema
var keySchemaRegistry = CreateSchemaRegistry(specifiedKeyAvroSchema, schemaRegistryUrl, schemaRegistryUsername, schemaRegistryPassword);
serializer = Activator.CreateInstance(typeof(AvroSerializer<>).MakeGenericType(keyType), keySchemaRegistry, null /* config */);
keySerializer = typeof(SyncOverAsyncSerializerExtensionMethods).GetMethod("AsSyncOverAsync").MakeGenericMethod(keyType).Invoke(null, new object[] { serializer });
}
}
Expand All @@ -197,7 +200,7 @@ internal static (object, object) ResolveSchemaRegistrySerializers(Type valueType
object valueSerializer = null;
object keySerializer = null;

var schemaRegistry = CreateSchemaRegistry(null, null, schemaRegistryUrl, schemaRegistryUsername, schemaRegistryPassword);
var schemaRegistry = CreateSchemaRegistry(null, schemaRegistryUrl, schemaRegistryUsername, schemaRegistryPassword);

if (typeof(GenericRecord).IsAssignableFrom(valueType) || typeof(ISpecificRecord).IsAssignableFrom(valueType))
{
Expand All @@ -215,11 +218,11 @@ internal static (object, object) ResolveSchemaRegistrySerializers(Type valueType
}


private static ISchemaRegistryClient CreateSchemaRegistry(string specifiedValueAvroSchema, string specifiedKeyAvroSchema, string schemaRegistryUrl, string schemaRegistryUsername, string schemaRegistryPassword)
private static ISchemaRegistryClient CreateSchemaRegistry(string specifiedAvroSchema, string schemaRegistryUrl, string schemaRegistryUsername, string schemaRegistryPassword)
{
if (!string.IsNullOrWhiteSpace(specifiedValueAvroSchema) || !string.IsNullOrWhiteSpace(specifiedKeyAvroSchema))
if (!string.IsNullOrWhiteSpace(specifiedAvroSchema))
{
return new LocalSchemaRegistry(specifiedValueAvroSchema, specifiedKeyAvroSchema);
return new LocalSchemaRegistry(specifiedAvroSchema);
}
if (schemaRegistryUrl != null)
{
Expand All @@ -231,7 +234,7 @@ private static ISchemaRegistryClient CreateSchemaRegistry(string specifiedValueA
}
return new CachedSchemaRegistryClient(schemaRegistryConfig.ToArray());
}
throw new ArgumentNullException(nameof(specifiedValueAvroSchema), $@"parameter is required when creating an generic avro serializer");
throw new ArgumentNullException(nameof(specifiedAvroSchema), $@"parameter is required when creating an generic avro serializer");
}

internal class GetKeyAndValueTypesResult
Expand Down Expand Up @@ -286,8 +289,6 @@ internal static GetKeyAndValueTypesResult GetKeyAndValueTypes(string valueAvroSc
}
}

// if schema registry is present, the types must be generic too?

(valueType, valueAvroSchema) = GetTypeAndSchema(valueType, valueAvroSchemaFromAttribute);
}

Expand Down Expand Up @@ -321,7 +322,7 @@ private static (Type type, string avroSchema) GetTypeAndSchema(Type type, string


/// <summary>
/// Gets if the type can be serialized/deserialized
/// Gets if the type can be serialized/deserialized.
/// </summary>
internal static bool IsDesSerType(Type type)
{
Expand Down
2 changes: 0 additions & 2 deletions test/Microsoft.Azure.WebJobs.Extensions.Kafka.EndToEndTests/TriggerFunctions.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -133,8 +133,6 @@ public static void Trigger(
}
}



internal static class MultiItem_KafkaEventData_String_With_Long_Key_Trigger
{
public static void Trigger(
Expand Down