KEFCore: KEFCoreDbContext

KEFCoreDbContext is a special class which helps to define the DbContext and use Entity Framework Core provider for Apache Kafka™:

KEFCoreDbContext inherits from DbContext: to define the model, and/or creating the database, see getting started in the docs and KEFCore usage
KEFCoreDbContext defines the following properties:
- KeySerDesSelectorType: the .NET type to be used to allocate an external serializer for Apache Kafka™ record key
- ValueSerDesSelectorType: the .NET type to be used to allocate an external serializer for Apache Kafka™ record value
- ValueContainerType: the .NET type to be used to allocate an external container class for Apache Kafka™ record value
- BootstrapServers: the server hosting the broker of Apache Kafka™
- ApplicationId: the application identifier used to identify the context
- TopicPrefix: the optional user defined name which is used to prepend every Topic which belongs to the application
- DefaultNumPartitions: the default number of partitions used when topics are created for each entity
- DefaultReplicationFactor: the replication factor to use when data are stored in Apache Kafka™
- DefaultConsumerInstances: the consumer instances to be allocated when UseCompactedReplicator is true
- UsePersistentStorage: set to true to use a persistent storage between multiple application startup
- UseEnumeratorWithPrefetch: set to true to prefer enumerator instances able to do a prefetch on data speeding up execution, used if UseKNetStreams is true and UseCompactedReplicator is false
- UseByteBufferDataTransfer: set to true to prefer data exchange in serializer instances
- UseDeletePolicyForTopic: set to true to enable delete cleanup policy
- UseCompactedReplicator: Use KNetCompactedReplicator instead of Apache Kafka™ Streams to manage data to or from topics
- UseKNetStreams: Setting this property to true the KNet version of Apache Kafka™ Streams is used instead of standard Apache Kafka™ Streams, the property is used if UseCompactedReplicator is false
- UseGlobalTable: Setting this property to true the engine based on Streams (i.e. UseCompactedReplicator is false will use Org.Apache.Kafka.Streams.Kstream.GlobalKTable (MASES.KNet.Streams.Kstream.GlobalKTable if UseKNetStreams is true) instead of Org.Apache.Kafka.Streams.Kstream.KTable (MASES.KNet.Streams.Kstream.KTable if UseKNetStreams is true) to manage local storage of information.
- ConsumerConfig: parameters to use for Producer
- ProducerConfig: parameters to use for Producer
- StreamsConfig: parameters to use for Apche Kafka™ Streams application
- TopicConfig: parameters to use on topic creation for each entity
- ManageEvents: Setting this property to true (default) the backend emits events on ChangeTracker
- ReadOnlyMode: Setting this property to true (default is false) if the engine shall reject any write operation, its value will be used to verify if topics has the proper rights AclOperation.WRITE and AclOperation.READ
- DefaultSynchronizationTimeout: The default timeout, expressed in milliseconds, KEFCore will wait for backend to be in-sync with Apache Kafka™ cluster. Setting this property to 0 the synchronization will be disabled
- UseStorePrefixScan: Set this property to true to enable prefix scan in engine, default is false
- UseStoreSingleKeyLookup: Set this property to true to enable single key look-up in engine, default is true
- UseStoreKeyRange: Set this property to true to enable key range look-up in engine, default is true
- UseStoreReverse: Set this property to true to enable reverse look-up in engine, default is true
- UseStoreReverseKeyRange: Set this property to true to reverse key range look-up in engine, default is true

How to use `KEFCoreDbContext` class

The most simple example of usage can be found in KEFCore usage. By default, KEFCoreDbContext automatically manages OnConfiguring method of DbContext:

KEFCoreDbContext checks the mandatory options like BootstrapServers and DbName
KEFCoreDbContext setup the options needed to use an Apache Kafka™ cluster:
- ~~default ConsumerConfig can be overridden using ConsumerConfig property of KEFCoreDbContext~~
- default ProducerConfig can be overridden using ProducerConfig property of KEFCoreDbContext
- default StreamsConfig can be overridden using StreamsConfig property of KEFCoreDbContext
- default TopicConfig can be overridden using TopicConfig property of KEFCoreDbContext

Default ConsumerConfig

Over the Apache Kafka™ defaults it applies:

EnableAutoCommit is true
AutoOffsetReset set to EARLIEST
AllowAutoCreateTopics set to false

Default ProducerConfig

Does not change anything over the Apache Kafka™ defaults

Default StreamsConfig