Introduce TexeraWorkflowCompilingService for Workflow Compilation

[bobbai00]

This PR adds a standalone web service called TexeraWorkflowCompilingService.

The purpose of having a standalone compilation service

Separate the Texera Workflow Compilation with Workflow Execution.

The configuration of this service

1. Web Server Config

All the configuration items are put in core/amber/src/main/resources/texera-compiler-web-config.yml. By default, this server runs at port 9090.

2. Application Config

This service shares the same application configuration file, i.e. core/amber/src/main/resources/application.conf. To ensure that JWT token can be recognized by both TexeraWebApplication and TexeraWorkflowCompilingService, user-sys.jwt.256-bit-secret must NOT be set as random, instead it must be set as a fixed 256-bit string.

The Endpoint provided by TexeraWorkflowCompilingService

A single endpoint is provided by this web application:

POST    /api/texera/compilation/{wid}

• request format: the serialized workflow json string
• response:
  • physicalPlan: Option[PhysicalPlan] // the physical plan of the workflow, if None, the compilation is failed
  • operatorInputSchemas: Map[String, List[Option[List[Attribute]]]]. // from OpId to list of Schema(List of attributes) indexed by port id
  • operatorErrors: Map[String, String] // from OpId to error of this operator

Future TODO after this PR

1. Use this web service when GUI is doing the workflow editing, maintain the physical plan in GUI.
2. Change all the deployment scripts, including terminate-daemon.sh, deploy-daemon.sh and Dockerfile to launch & terminate this web service
3. Clean up the code in core/amber/src/main/scala/edu/uci/ics/texera/workflow/common/workflow/WorkflowCompiler.scala and core/amber/src/main/scala/edu/uci/ics/texera/web/service/WorkflowExecutionService.scala

[Yicong-Huang]

Please address the comments. For some topics feel free to have discussions.

[Yicong-Huang]

@bobbai00 please reply to previous comments so I know what's changed or to expect.

[Yicong-Huang]

LGTM. Left some minor comments in code.