[WIP] Generate server implementation for pure Python business logic

[crisidev]

Motivation and Context

Pyo3 will allow us to generate an idiomatic Python implementation which is exported from Rust as a shared library.

The framework heavy-lifting will be handled completely in Rust, while the business logic will be implemented in pure Python.

Example

# Import the shared library application, context and input/output types.
from pokemon_service import PokemonService, SharedContext
from pokemon_service.model import PokemonDescriptionInput, PokemonDescriptionOutput, AuthError
from pokemon_service.http import Request
# import application specific code.
from .database import DatabasePool

# Define a context class to be shared between handlers
@dataclass
class Context:
    db = DatabasePool()
 
# Create the application and register context.   
app = PokemonService()
app.context(Context())

# Define a middleware function.
@app.middleware
async def auth_middleware(request: Request):
    if request.headers.get("a-token") != "i_am_so_secret":
        raise AuthError("Invalid a-token")

# Define the operation using the type imported from Rust.
@app.pokemon_description
async def pokemon_description(input: PokemonDescriptionInput, ctx: SharedContext) -> PokemonDescriptionOutput:
    description = await ctx.db.get_description(input.name)
    return PokemonDescriptionOutput(description)

# Start the application. 
app.run()

Features

• Python subproject scaffolding - [Server] Implement Gradle subprojects and scaffolding for the Python server. #1366
• Runtime crate and shared socket - Implement Python runtime crate and shared socket #1399
• Code sharing between :codegen, :codegen-server and :codegen-server:python Gradle projects. - Codegenerate StructureShape, BlobShape, application, server and Python runtime #1403
• Object model for input / outputs / errors. - Codegenerate StructureShape, BlobShape, application, server and Python runtime #1403
• Operation wrappers to execute Python code inside Rust. - Codegenerate StructureShape, BlobShape, application, server and Python runtime #1403
• Shared state/context support. - Codegenerate StructureShape, BlobShape, application, server and Python runtime #1403
• Support for both asyncio and traditional Python code. - Codegenerate StructureShape, BlobShape, application, server and Python runtime #1403
• Support spawning multiple interpreters using a shared socket. - Codegenerate StructureShape, BlobShape, application, server and Python runtime #1403
• Handle Python exceptions inside infallible operations. - Codegenerate StructureShape, BlobShape, application, server and Python runtime #1403
• Inject tracing into the Python logger system. - Implement Python runtime crate and shared socket #1399
• Enum support - Codegenerate StructureShape, BlobShape, application, server and Python runtime #1403
• Signal handling. - Export a usable Python implementation via shared library #1476
• DateTime type support. - Export a usable Python implementation via shared library #1476
• Generate PyO3 export module. - Export a usable Python implementation via shared library #1476
• Python API example. - Export a usable Python implementation via shared library #1476
• Integration testing in CI. - Export a usable Python implementation via shared library #1476
• Cast Python exceptions into Rust errors - Export a usable Python implementation via shared library #1476
• Generate Python application example. - Codegenerate Python application example and add explicit cast during JSON deserialization #1520
• Cast Python non-primitive types into types coming from aws-smithy-types during deserialization. - Codegenerate Python application example and add explicit cast during JSON deserialization #1520
• Streaming body support. - Fix bug in coroutine scheduling. Add ByteStream implementation and simplify Python symbol visitor. #1633
• Support for custom pure-Python request middleware - [Python] Allow to run pure Python request middlewares inside a Tower service #1734
• Support for custom pure-Python response middleware - [Python] Support pure Python implementation of response middleware #1754
• Lambda support - [Python] Lambda support #1750
• HTTPS support - [Python] HTTPS support #1751
• Support type hinting - Python: Type-stub generation for SSDKs #2149
• Union support. - Implement Python unions #2427
• Event streaming support - [Python] Support event streaming trait #1752
• [Python] Support recursive shapes that are boxed in Rust #2476
• Support aws.protocoltests.json10#JsonRpc10 #2479
• [Python] Automatically generate stubs #2576
• [Python] Improve Python stubs generation #2606
• [Python] Add APIGW info to the lambda context #2485
• [Python] Middleware customisation support #2578
• [Python] Support aws.protocoltests.json#JsonProtocol test model #2477