Architecture of zeppelin-sqlflow

[Klay1124]

Zeppelin is essentially a web application. It starts the interpreter as an independent JVM process, interactively executes code fragments of various languages, and returns the results to the front-end UI in the form of HTML code fragments.

Zeppelin interpreter module: in order to support multi language notebook, the interpreter interface of each language is abstracted, including display, scheduling, dependency and thirft communication protocol with Zeppelin engine.

There are four important files in the development of sqlflow interpreter :

1. SQLFlowInterpreter.java
   This file is to let sqlflow inherit the interpreter interface provided by Zeppelin, so as to connect the two and realize the abstract class of Zeppelin. In this file, you can read the configuration file parameters, construct the sqlflow client, start and close the interpreter, and so on.
2. EnvironmentSpecificSQLFlowClient.java
   Create a class of sqlflow client.
3. MessageHandlerZeeplin.java
   Front end display control class. Display the front-end interface output results: message header, message body, picture, error information, etc.
4. interpreter-setting.json
   Create the interpreter configuration file. Interceptor settings file, which parameters the foreground needs, need to be written in the configuration file, in order to transfer to the background.