fix(fastapi): increase recursion limit during tests

The default recursion limit used by Docker's archlinux:base-devel
Python package becomes problematic in some cases when running tests
against our FastAPI application using starlette.testclient.TestClient
(aliased to fastapi.testclient.TestClient). starlette ends up with
test failures because it exceeds the recursion limit, but this only
happens when using the `TestClient`. When the ASGI servers are run,
this is not an issue and so in that case, the recursion limit has
not been touched.

This change uses a `TEST_RECURSION_LIMIT` environment variable to
modify the recursion limit of the FastAPI application. This variable
is, by default, only supplied when running pytests in Docker, but
can be force-supplied by the user.

TEST_RECURSION_LIMIT=10000 has been added to `.env` and `.gitlab-ci.yml`.

Signed-off-by: Kevin Morris <kevr@0cost.org>

.env

@@ -4,3 +4,4 @@ MARIADB_SOCKET_DIR="/var/run/mysqld/"
 CGIT_CLONE_PREFIX_PHP=https://localhost:8443
 CGIT_CLONE_PREFIX_FASTAPI=https://localhost:8444
 GIT_DATA_DIR="./aur.git/"
+TEST_RECURSION_LIMIT=10000

.gitlab-ci.yml

@@ -9,6 +9,7 @@ cache:
 variables:
   AUR_CONFIG: conf/config # Default MySQL config setup in before_script.
   DB_HOST: localhost
+  TEST_RECURSION_LIMIT: 10000
 
 before_script:
   - export PATH="$HOME/.poetry/bin:${PATH}"

aurweb/asgi.py

@@ -1,5 +1,7 @@
 import asyncio
 import http
+import os
+import sys
 import typing
 
 from urllib.parse import quote_plus
@@ -25,6 +27,19 @@ app = FastAPI(exception_handlers=errors.exceptions)
 
 @app.on_event("startup")
 async def app_startup():
+    # https://stackoverflow.com/questions/67054759/about-the-maximum-recursion-error-in-fastapi
+    # Test failures have been observed by internal starlette code when
+    # using starlette.testclient.TestClient. Looking around in regards
+    # to the recursion error has really not recommended a course of action
+    # other than increasing the recursion limit. For now, that is how
+    # we handle the issue: an optional TEST_RECURSION_LIMIT env var
+    # provided by the user. Docker uses .env's TEST_RECURSION_LIMIT
+    # when running test suites.
+    # TODO: Find a proper fix to this issue.
+    recursion_limit = int(os.environ.get(
+        "TEST_RECURSION_LIMIT", sys.getrecursionlimit()))
+    sys.setrecursionlimit(recursion_limit)
+
     session_secret = aurweb.config.get("fastapi", "session_secret")
     if not session_secret:
         raise Exception("[fastapi] session_secret must not be empty")

docker-compose.yml

@@ -216,6 +216,7 @@ services:
     init: true
     environment:
       - AUR_CONFIG=conf/config
+      - TEST_RECURSION_LIMIT=${TEST_RECURSION_LIMIT}
     entrypoint: /docker/test-mysql-entrypoint.sh
     command: /docker/scripts/run-pytests.sh clean
     stdin_open: true
@@ -241,6 +242,7 @@ services:
     init: true
     environment:
       - AUR_CONFIG=conf/config.sqlite
+      - TEST_RECURSION_LIMIT=${TEST_RECURSION_LIMIT}
     entrypoint: /docker/test-sqlite-entrypoint.sh
     command: setup-sqlite.sh run-pytests.sh clean
     stdin_open: true
@@ -262,6 +264,7 @@ services:
     init: true
     environment:
       - AUR_CONFIG=conf/config
+      - TEST_RECURSION_LIMIT=${TEST_RECURSION_LIMIT}
     entrypoint: /docker/tests-entrypoint.sh
     command: setup-sqlite.sh run-tests.sh
     stdin_open: true