feat: FastAPI support

Add support for the FastAPI framework. Load it automatically when
uvicorn is run with a FastAPI app.

Author: apotterri

_appmap/event.py

@@ -10,11 +10,11 @@
 from .recorder import Recorder
 from .utils import (
     FnType,
+    FqFnName,
     appmap_tls,
     compact_dict,
     fqname,
     get_function_location,
-    split_function_name,
 )
 
 logger = Env.current.getLogger(__name__)
@@ -173,7 +173,7 @@ def to_dict(self, value):
 
 
 class CallEvent(Event):
-    __slots__ = ["_fn", "static", "receiver", "parameters", "labels"]
+    __slots__ = ["_fn", "_fqfn", "static", "receiver", "parameters", "labels"]
 
     @staticmethod
     def make(fn, fntype):
@@ -209,10 +209,9 @@ def make_params(filterable):
             # going to log a message about a mismatch.
             wrapped_sig = inspect.signature(fn, follow_wrapped=True)
             if sig != wrapped_sig:
-                logger.debug(
-                    "signature of wrapper %s.%s doesn't match wrapped",
-                    *split_function_name(fn)
-                )
+                logger.debug("signature of wrapper %r doesn't match wrapped", fn)
+                logger.debug("sig: %r", sig)
+                logger.debug("wrapped_sig: %r", wrapped_sig)
 
         return [Param(p) for p in sig.parameters.values()]
 
@@ -270,17 +269,17 @@ def set_params(params, instance, args, kwargs):
     @property
     @lru_cache(maxsize=None)
     def function_name(self):
-        return split_function_name(self._fn)
+        return self._fqfn.fqfn
 
     @property
     @lru_cache(maxsize=None)
     def defined_class(self):
-        return self.function_name[0]
+        return self._fqfn.fqclass
 
     @property
     @lru_cache(maxsize=None)
     def method_id(self):
-        return self.function_name[1]
+        return self._fqfn.fqfn[1]
 
     @property
     @lru_cache(maxsize=None)
@@ -308,6 +307,7 @@ def comment(self):
     def __init__(self, fn, fntype, parameters, labels):
         super().__init__("call")
         self._fn = fn
+        self._fqfn = FqFnName(fn)
         self.static = fntype in FnType.STATIC | FnType.CLASS | FnType.MODULE
         self.receiver = None
         if fntype in FnType.CLASS | FnType.INSTANCE:
@@ -351,7 +351,15 @@ class MessageEvent(Event):  # pylint: disable=too-few-public-methods
     def __init__(self, message_parameters):
         super().__init__("call")
         self.message = []
-        for name, value in message_parameters.items():
+        self.message_parameters = message_parameters
+
+    @property
+    def message_parameters(self):
+        return self.message
+
+    @message_parameters.setter
+    def message_parameters(self, params):
+        for name, value in params.items():
             message_object = describe_value(name, value)
             self.message.append(message_object)
 
@@ -386,6 +394,7 @@ def __init__(self, request_method, url, message_parameters, headers=None):
 
 
 # pylint: disable=too-few-public-methods
+_NORMALIZED_PATH_INFO_ATTR = "normalized_path_info"
 class HttpServerRequestEvent(MessageEvent):
     """A call AppMap event representing an HTTP server request."""
 
@@ -406,7 +415,7 @@ def __init__(
             "request_method": request_method,
             "protocol": protocol,
             "path_info": path_info,
-            "normalized_path_info": normalized_path_info,
+            _NORMALIZED_PATH_INFO_ATTR: normalized_path_info,
         }
 
         if headers is not None:
@@ -420,6 +429,14 @@ def __init__(
 
         self.http_server_request = compact_dict(request)
 
+    @property
+    def normalized_path_info(self):
+        return self.http_server_request.get(_NORMALIZED_PATH_INFO_ATTR, None)
+
+    @normalized_path_info.setter
+    def normalized_path_info(self, npi):
+        self.http_server_request[_NORMALIZED_PATH_INFO_ATTR] = npi
+
 
 class ReturnEvent(Event):
     __slots__ = ["parent_id", "elapsed"]

_appmap/fastapi.py

@@ -0,0 +1,32 @@
+"""
+This file contains a FastAPI app that is mounted on /_appmap to expose the remote-recording endpoint
+in a user's app.
+
+It should only be imported if other code has already verified that FastAPI is available.
+"""
+
+from fastapi import FastAPI, Response
+
+from . import remote_recording
+
+app = FastAPI()
+
+
+def _rr_response(fn):
+    body, rrstatus = fn()
+    return Response(content=body, status_code=rrstatus, media_type="application/json")
+
+
+@app.get("/record")
+def status():
+    return _rr_response(remote_recording.status)
+
+
+@app.post("/record")
+def start():
+    return _rr_response(remote_recording.start)
+
+
+@app.delete("/record")
+def stop():
+    return _rr_response(remote_recording.stop)

_appmap/importer.py

@@ -10,56 +10,49 @@
 from _appmap import wrapt
 
 from .env import Env
-from .utils import FnType
+from .utils import FnType, Scope
 
 logger = Env.current.getLogger(__name__)
 
 
-Filterable = namedtuple("Filterable", "fqname obj")
+Filterable = namedtuple("Filterable", "scope fqname obj")
 
 
 class FilterableMod(Filterable):
     __slots__ = ()
 
     def __new__(cls, mod):
         fqname = mod.__name__
-        return super(FilterableMod, cls).__new__(cls, fqname, mod)
-
-    def classify_fn(self, _):
-        return FnType.MODULE
+        return super(FilterableMod, cls).__new__(cls, Scope.MODULE, fqname, mod)
 
 
 class FilterableCls(Filterable):
     __slots__ = ()
 
     def __new__(cls, clazz):
         fqname = "%s.%s" % (clazz.__module__, clazz.__qualname__)
-        return super(FilterableCls, cls).__new__(cls, fqname, clazz)
-
-    def classify_fn(self, static_fn):
-        return FnType.classify(static_fn)
+        return super(FilterableCls, cls).__new__(cls, Scope.CLASS, fqname, clazz)
 
 
 class FilterableFn(
     namedtuple(
         "FilterableFn",
-        Filterable._fields
-        + (
-            "scope",
-            "static_fn",
-        ),
+        Filterable._fields + ("static_fn",),
     )
 ):
     __slots__ = ()
 
     def __new__(cls, scope, fn, static_fn):
         fqname = "%s.%s" % (scope.fqname, fn.__name__)
-        self = super(FilterableFn, cls).__new__(cls, fqname, fn, scope, static_fn)
+        self = super(FilterableFn, cls).__new__(cls, scope.scope, fqname, fn, static_fn)
         return self
 
     @property
     def fntype(self):
-        return self.scope.classify_fn(self.static_fn)
+        if self.scope == Scope.MODULE:
+            return FnType.MODULE
+
+        return FnType.classify(self.static_fn)
 
 
 class Filter(ABC):  # pylint: disable=too-few-public-methods
@@ -161,6 +154,17 @@ def initialize(cls):
     def use_filter(cls, filter_class):
         cls.filter_stack.append(filter_class)
 
+    @classmethod
+    def instrument_function(cls, fn_name, filterableFn: FilterableFn, selected_functions=None):
+        # Only instrument the function if it was specifically called out for the package
+        # (e.g. because it should be labeled), or it's included by the filters
+        matched = cls.filter_chain.filter(filterableFn)
+        selected = selected_functions and fn_name in selected_functions
+        if selected or matched:
+            return cls.filter_chain.wrap(filterableFn)
+
+        return filterableFn.obj
+
     @classmethod
     def do_import(cls, *args, **kwargs):
         mod = args[0]
@@ -177,15 +181,10 @@ def instrument_functions(filterable, selected_functions=None):
             logger.trace("  functions %s", functions)
 
             for fn_name, static_fn, fn in functions:
-                # Only instrument the function if it was specifically called out for the package
-                # (e.g. because it should be labeled), or it's included by the filters
                 filterableFn = FilterableFn(filterable, fn, static_fn)
-                matched = cls.filter_chain.filter(filterableFn)
-                selected = selected_functions and fn_name in selected_functions
-                if selected or matched:
-                    new_fn = cls.filter_chain.wrap(filterableFn)
-                    if fn != new_fn:
-                        wrapt.wrap_function_wrapper(filterable.obj, fn_name, new_fn)
+                new_fn = cls.instrument_function(fn_name, filterableFn, selected_functions)
+                if new_fn != fn:
+                    wrapt.wrap_function_wrapper(filterable.obj, fn_name, new_fn)
 
         # Import Config here, to avoid circular top-level imports.
         from .configuration import Config  # pylint: disable=import-outside-toplevel

_appmap/remote_recording.py

@@ -1,4 +1,5 @@
-""" remote_recording is a Flask app that can be mounted to expose the remote-recording endpoint. """
+""" remote_recording contains the functions neccessary to implement a remote-recording endpoint. """
+
 import json
 from threading import Lock
 

_appmap/test/data/fastapi/appmap.yml

@@ -0,0 +1,3 @@
+name: FastAPITest
+packages:
+- path: fastapiapp

_appmap/test/data/fastapi/fastapiapp/__init__.py

@@ -0,0 +1,67 @@
+"""
+Rudimentary FastAPI application for testing.
+
+NB: This should not explicitly reference the `appmap` module in any way. Doing so invalidates
+testing of record-by-default.
+"""
+# pylint: disable=missing-function-docstring
+
+from typing import List
+
+from fastapi import FastAPI, Query, Request, Response
+
+app = FastAPI()
+
+
+@app.get("/")
+def hello_world():
+    return {"Hello": "World!"}
+
+
+@app.post("/echo")
+async def echo(request: Request):
+    body = await request.body()
+    return Response(content=body, media_type="application/json")
+
+
+@app.get("/test")
+async def get_test(my_params: List[str] = Query(None)):
+    response = Response(content="testing", media_type="text/html; charset=utf-8")
+    response.headers["ETag"] = "W/01"
+    return response
+
+
+@app.post("/test")
+async def post_test(request: Request):
+    await request.json()
+    response = Response(content='{"test":true}', media_type="application/json")
+    response.headers["ETag"] = "W/01"
+    return response
+
+
+@app.get("/user/{username}")
+def get_user_profile(username):
+    # show the user profile for that user
+    return {"user": username}
+
+
+@app.get("/post/{post_id:int}")
+def get_post(post_id):
+    # show the post with the given id, the id is an integer
+    return {"post": post_id}
+
+
+@app.get("/post/{username}/{post_id:int}/summary")
+def get_user_post(username, post_id):
+    # Show the summary of a user's post
+    return {"user": username, "post": post_id}
+
+
+@app.get("/{org:int}/posts/{username}")
+def get_org_user_posts(org, username):
+    return {"org": org, "username": username}
+
+
+@app.get("/exception")
+def raise_exception():
+    raise Exception("An exception")

_appmap/test/data/fastapi/fastapiapp/main.py

@@ -0,0 +1 @@
+import appmap

_appmap/test/data/fastapi/init/sitecustomize.py

@@ -0,0 +1,14 @@
+import pytest
+from fastapi.testclient import TestClient
+from fastapiapp import app
+
+
+@pytest.fixture
+def client():
+    yield TestClient(app)
+
+
+def test_request(client):
+    response = client.get("/")
+
+    assert response.status_code == 200

_appmap/test/data/fastapi/test_app.py

@@ -9,19 +9,15 @@
                 "protocol": "HTTP/1.1",
                 "request_method": "GET"
             },
-            "id": 1,
-            "thread_id": 1
+            "id": 1
         },
         {
             "event": "return",
             "http_server_response": {
-                "headers": { "Content-Type": "text/html; charset=utf-8" },
-                "mime_type": "text/html; charset=utf-8",
                 "status_code": 200
             },
             "id": 2,
-            "parent_id": 1,
-            "thread_id": 1
+            "parent_id": 1
         },
         {
             "event": "call",
@@ -31,19 +27,15 @@
                 "protocol": "HTTP/1.1",
                 "request_method": "GET"
             },
-            "id": 3,
-            "thread_id": 1
+            "id": 3
         },
         {
             "event": "return",
             "http_server_response": {
-                "headers": { "Content-Type": "text/html; charset=utf-8" },
-                "mime_type": "text/html; charset=utf-8",
                 "status_code": 200
             },
             "id": 4,
-            "parent_id": 3,
-            "thread_id": 1
+            "parent_id": 3
         }
     ],
     "metadata": {