THIS IS A TEST INSTANCE. ALL YOUR CHANGES WILL BE LOST!!!!
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Introduction
Apache Geode is a data management platform that provides real-time, consistent access to data-intensive applications throughout widely distributed cloud architectures. While it currently has high-speed client interfaces for Java, C++ and .NET there is both a need to create lighter-weight clients and a demand to access Geode from other programming languages. Unfortunately, the existing client-server protocol is undocumented. It evolved over time and is overly complex to meet either of these needs.
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Protocol Requirements
In the evaluation or definition of any protocol, it expected that the evaluated protocol/framework meets the following requirements:
Versioning: The protocol has to provide version information, in order to distinguish different protocol versions from one another.
Correlation Id: This number is a unique identifier that allows the system to correlate requests and responses.
Object Type: The type of a serialized object.
Response Type: It indicates whether a response is partial or complete.
ErrorCodes: It indicates the problem with API invocation.
Chunk Response: The ability to send a large response in multiple smaller, more manageable chunks.
Continuous Response: Client can register(Observer pattern) for events and then server notify the client if those events occur.
Request: The request message to be sent
Response: The response message received in relation to a request message
Request Format: Format of request API and its parameters, which client wants to invoke.
Response Format: Format for API return value, which client invoked.
Message: The generic construct that represents a message that is to be sent which contains a Message Header and Request/Response.
Serialized Byte Order: Big Endian
Approach
During the investigation into frameworks that would "lower the barrier of entry," it became evident that there are two approaches that can be taken to solve the problem:
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From an architectural perspective, the protocol proposal can be broken into two areas of interest:
- A Transport Layer (TCP, UDP, HTTP, etc..)
- Message encoding/decoding Layer
This proposal will:
- Define the message structure and protocol to be agnostic of transport used.
- Evaluate different Message Serialization Frameworks and RPC Frameworks.
Message Structure Definition
All details relating to the Message structure definition can be found here.
Connect
In order to fit into the existing Geode client/server infrastructure, we will be leveraging the current Geode "cache server" component. It accepts an initial byte that tells it what type of client is connecting to the server and how the client should be handled. A client using the new protocol can connect with the Geode server by sending a protocol byte. Initially, we will support the following two protocols:
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