Replace starlette-context with BaseHTTPMiddleware

this is still not ideal, as the entire response will be loaded into
memory. This is a problem with streaming responses.
encode/starlette#1012 (comment)
is actually enlightening here:

> "This means this class will either load the entirety of streaming requests into memory (this issue) and run the background before returning the response (galaxyproject#919 ), or if we fix those problems, that it will then encourage users to leave resources in a pending or open state, an arguably worse result. In short, it's problematic."

Which is exactly what we'd be doing with a middleware, keeping resources
open for longer than necessary, which we need to avoid if we ever want
to run background / async tasks.  I think the solution here what we
already had, path operation dependencies.

lib/galaxy/dependencies/dev-requirements.txt

@@ -209,7 +209,6 @@ sqlalchemy==1.3.22; (python_version >= "2.7" and python_full_version < "3.0.0")
 sqlitedict==1.7.0
 sqlparse==0.4.1; python_version >= "3.5"
 starlette==0.13.6; python_version >= "3.6" and python_version < "4.0"
-starlette-context==0.3.1; python_version >= "3.7"
 stevedore==3.3.0; python_version >= "3.6"
 svgwrite==1.4.1; python_version >= "3.6"
 tempita==0.5.2

lib/galaxy/dependencies/pinned-requirements.txt

@@ -169,7 +169,6 @@ sqlalchemy==1.3.22; (python_version >= "2.7" and python_full_version < "3.0.0")
 sqlitedict==1.7.0
 sqlparse==0.4.1; python_version >= "3.5"
 starlette==0.13.6; python_version >= "3.6" and python_version < "4.0"
-starlette-context==0.3.1; python_version >= "3.7"
 stevedore==3.3.0; python_version >= "3.6"
 svgwrite==1.4.1; python_version >= "3.6"
 tempita==0.5.2

lib/galaxy/model/base.py

@@ -14,6 +14,7 @@
     scoped_session,
     sessionmaker
 )
+
 from galaxy.util.bunch import Bunch
 
 REQUEST_ID = ContextVar('request_id', default=None)

lib/galaxy/webapps/galaxy/fast_app.py

@@ -1,12 +1,12 @@
+from uuid import uuid4
+
 from fastapi import FastAPI, Request
 from fastapi.exceptions import RequestValidationError
 from fastapi.middleware.wsgi import WSGIMiddleware
 from fastapi.responses import JSONResponse
+from starlette.middleware.base import BaseHTTPMiddleware
 from starlette.middleware.cors import CORSMiddleware
 from starlette.responses import Response
-from starlette_context import plugins
-from starlette_context import context
-from starlette_context.middleware import RawContextMiddleware
 
 from galaxy.exceptions import MessageException
 from galaxy.web.framework.base import walk_controller_modules
@@ -115,31 +115,30 @@ async def preflight_handler(request: Request, rest_of_path: str) -> Response:
             return response
 
 
-class SqlSessionPlugin(plugins.Plugin):
-    """
-    Stores X-Request-ID set by the RequestIdPlugin in a separate contexvar
-    and sets and unsets the session.
-    """
-    key = 'X-Request-ID'
+def add_sa_session_middleware(app: FastAPI, gx_app):
+    class CustomHeaderMiddleware(BaseHTTPMiddleware):
 
-    def __init__(self, *args, gx_app=None, **kwargs):
-        super().__init__(*args, **kwargs)
-        self.gx_app = gx_app
+        def __init__(self, app, gx_app) -> None:
+            super().__init__(app)
+            self.gx_app = gx_app
 
-    async def process_request(self, request):
-        self.gx_app.model.set_request_id(context.data[self.key])
-        return context.data['X-Request-ID']
+        async def dispatch(self, request, call_next):
+            request_id = uuid4().hex
+            self.gx_app.model.set_request_id(request_id)
+            try:
+                response = await call_next(request)
+            finally:
+                self.gx_app.model.unset_request_id(request_id)
+            return response
 
-    async def enrich_response(self, arg) -> None:
-        self.gx_app.model.unset_request_id(context.data[self.key])
+    app.add_middleware(CustomHeaderMiddleware, gx_app=gx_app)
 
 
 def initialize_fast_app(gx_webapp, gx_app):
     app = FastAPI(
         openapi_tags=api_tags_metadata
     )
-    app.add_middleware(RawContextMiddleware, plugins=(SqlSessionPlugin(gx_app=gx_app),))
-    app.add_middleware(RawContextMiddleware, plugins=(plugins.RequestIdPlugin(force_new_uuid=True),))
+    add_sa_session_middleware(app, gx_app)
     add_exception_handler(app)
     add_galaxy_middleware(app, gx_app)
     wsgi_handler = WSGIMiddleware(gx_webapp)

pyproject.toml

@@ -70,7 +70,6 @@ sqlalchemy-migrate = "*"
 SQLAlchemy-Utils = "!=0.36.8"  # https://github.com/kvesteri/sqlalchemy-utils/issues/462
 sqlitedict = "*"
 sqlparse = "*"
-starlette-context = "*"
 svgwrite = "*"
 uvicorn = "*"
 WebOb = "*"

test/unit/api/test_fastapi.py

@@ -10,7 +10,6 @@
     add_exception_handler,
     add_sa_session_middleware,
 )
-
 from ..unittest_utils.galaxy_mock import MockApp
 
 app = FastAPI()
@@ -28,6 +27,7 @@ def is_valid_uuid(val):
 class UnexpectedException(Exception):
     pass
 
+
 def get_app():
     global GX_APP
     if GX_APP is None:
@@ -64,4 +64,4 @@ def test_sa_session_middleware():
     assert gx_app.model.scoped_registry.registry == {}
     with pytest.raises(UnexpectedException):
         response = client.get("/internal_server_error")
-    assert gx_app.model.scoped_registry.registry == {}
+    assert gx_app.model.scoped_registry.registry == {}