feat(gpRc): update FDL lexer/parser to support service and rpc definitions

[ayush00git]

Why?

Using fory with gRPCs forced using the protobuffs for the services and methods of a class. Users needed to define separate files for generating stubs. Which turns their focus on using protobuff completely, ignoring the fory's performance.

What does this PR do?

Adds the parser for rpc methods and services to allow users use FDL with gRPC.

Added Keywords

service
rpc
returns
stream

Changes Made

1. compiler/fory_compiler/ir/ast.py

Added RpcMethod and Service Data classes.

@dataclass
class Service:
    """A service definition."""

    name: str
    methods: List[RpcMethod] = field(default_factory=list)
    options: dict = field(default_factory=dict)
    line: int = 0
    column: int = 0
    location: Optional[SourceLocation] = None

    def __repr__(self) -> str:
        opts_str = f", options={len(self.options)}" if self.options else ""
        return f"Service({self.name}, methods={len(self.methods)}{opts_str})"

2. compiler/fory_compiler/frontend/fdl/lexer.py

• Added the SERVICE RPC RETURNS STREAM to the TokenType enum
• Mapped Keywords in Lexer.Keywords

    SERVICE = auto()
    RPC = auto()
    RETURNS = auto()
    STREAM = auto()

   "service": TokenType.SERVICE,
   "rpc": TokenType.RPC,
   "returns": TokenType.RETURNS,
   "stream": TokenType.STREAM,

3. compiler/fory_compiler/frontend/fdl/parser.py

• Added the parse_service and parse_rpc_method method.

    def parse_service(self) -> Service:
        """Parse a service definition: service Greeter { rpc ... }"""
        start = self.current()
        self.consume(TokenType.SERVICE)
        name = self.consume(TokenType.IDENT, "Expected service name").value
        self.consume(TokenType.LBRACE, "Expected '{' after service name")
.....

    def parse_rpc_method(self) -> RpcMethod:
        """Parse an RPC method: rpc Name (stream? Req) returns (stream? Res) { option ... };"""
        start = self.current()
        self.consume(TokenType.RPC)
        name = self.consume(TokenType.IDENT, "Expected method name").value

        # Parse request type
        self.consume(TokenType.LPAREN, "Expected '(' before request type")
        client_streaming = False
        if self.check(TokenType.STREAM):
            self.advance()
            client_streaming = True

4. Done the same updates just a slight different based on implementations for the protobuffs and flatbuffers.

Related issues

• Closes [Compiler][gRPC][FDL] Parse service/rpc/stream in FDL frontend #3268

Does this PR introduce any user-facing change?

• Does this PR introduce any public API change?
  This PR extends the FDL language with support for service definitions using service rpc returns and stream keywords. This allows users to define gRPC services directly in their FDL schemas.
• Does this PR introduce any binary protocol compatibility change?

Benchmark

N/A

[ayush00git]

Hey @chaokunyang
Give it a review and let me know the desired changes. Meanwhile i'm working on the #3269

[chaokunyang]

You also need to update protobuf and flatbuffers idl parser and add tests

[ayush00git]

Hey @chaokunyang
I've updated the proto and fbs parsers as well, have a review and let me know.

[chaokunyang]

LGTM