ci: enable exception replay in Django profile job (#11014)

We enable Exception Replay in the Django profile workflow and create a
scenario that leads to an exception to profile the relevant code paths.

## Checklist
- [x] PR author has checked that all the criteria below are met
- The PR description includes an overview of the change
- The PR description articulates the motivation for the change
- The change includes tests OR the PR description describes a testing
strategy
- The PR description notes risks associated with the change, if any
- Newly-added code is easy to change
- The change follows the [library release note
guidelines](https://ddtrace.readthedocs.io/en/stable/releasenotes.html)
- The change includes or references documentation updates if necessary
- Backport labels are set (if
[applicable](https://ddtrace.readthedocs.io/en/latest/contributing.html#backporting))

## Reviewer Checklist
- [x] Reviewer has checked that all the criteria below are met
- Title is accurate
- All changes are related to the pull request's stated goal
- Avoids breaking
[API](https://ddtrace.readthedocs.io/en/stable/versioning.html#interfaces)
changes
- Testing strategy adequately addresses listed risks
- Newly-added code is easy to change
- Release note makes sense to a user of the library
- If necessary, author has acknowledged and discussed the performance
implications of this PR as reported in the benchmarks PR comment
- Backport labels are set in a manner that is consistent with the
[release branch maintenance
policy](https://ddtrace.readthedocs.io/en/latest/contributing.html#backporting)

(cherry picked from commit 34d69be)

.github/workflows/django-overhead-profile.yml

@@ -26,6 +26,7 @@ jobs:
       DD_PROFILING_ENABLED: "1"
       DD_PROFILING_STACK_V2_ENABLED: ${{ matrix.stack_v2 }}
       DD_PROFILING_OUTPUT_PPROF: ${{ github.workspace }}/prefix/artifacts/ddtrace_profile
+      DD_EXCEPTION_REPLAY_ENABLED: "1"
     defaults:
       run:
         working-directory: ddtrace

scripts/profiles/django-simple/k6-exc.js

@@ -0,0 +1,10 @@
+import http from 'k6/http';
+
+export const options = {
+    duration: '60s',
+    vus: 100,
+};
+
+export default function () {
+    const res = http.get('http://127.0.0.1:8080/polls/123/results/');
+}

scripts/profiles/django-simple/k6-load.js

@@ -1,11 +1,10 @@
 import http from 'k6/http';
-import { sleep } from 'k6';
 
 export const options = {
     duration: '60s',
     vus: 100,
 };
 
 export default function () {
-    const res = http.get('http://127.0.0.1:8000/accounts/signup/');
+    const res = http.get('http://127.0.0.1:8080/polls/123/vote/');
 }

scripts/profiles/django-simple/run.sh

@@ -9,59 +9,83 @@ AUSTIN_EXPOSURE=5  # sec
 
 test -f ${PREFIX}/gunicorn.pid && (kill -9 `cat ${PREFIX}/gunicorn.pid` ; sleep 3) || rm -f ${PREFIX}/gunicorn.pid
 pkill k6 || true
-test -d ${PREFIX}/artifacts && rm -rf ${PREFIX}/artifacts || mkdir -p ${PREFIX}/artifacts
+pkill -9 -f uwsgi || true
+test -d ${PREFIX}/artifacts && rm -rf ${PREFIX}/artifacts
+mkdir -p ${PREFIX}/artifacts
 
 sudo echo "sudo OK"
 
+sudo rm -f ${PREFIX}/uwsgi.pid
+
 function profile_with_load {
     name=${1}
+    scenario=${2}
+
+    echo "- profiling for ${name}"
 
     sleep 3
-    ${PREFIX}/k6*/k6 run --quiet scripts/profiles/django-simple/k6-load.js &
+    echo "Starting load"
+    ${PREFIX}/k6*/k6 run --quiet scripts/profiles/django-simple/k6-${scenario}.js &
         sleep 2
-        sudo `which austin` -bsCi ${AUSTIN_INTERVAL} -o ${PREFIX}/artifacts/${name}.mojo -p `cat ${PREFIX}/gunicorn.pid` -x ${AUSTIN_EXPOSURE}
-        LC_ALL=C sed -i 's|/home/runner/work/dd-trace-py/dd-trace-py/ddtrace/||g' ${PREFIX}/artifacts/${name}.mojo
+        echo "Attaching Austin to $(cat ${PREFIX}/uwsgi.pid)"
+        sudo `which austin` -bsCi ${AUSTIN_INTERVAL} -o ${PREFIX}/artifacts/${scenario}_${name}.mojo -p `cat ${PREFIX}/uwsgi.pid` -x ${AUSTIN_EXPOSURE}
+        LC_ALL=C sed -i 's|/home/runner/work/dd-trace-py/dd-trace-py/ddtrace/||g' ${PREFIX}/artifacts/${scenario}_${name}.mojo
+    echo "Stopping load"
     pkill k6
 }
 
 source ${PREFIX}/bin/activate
 
-export DJANGO_SETTINGS_MODULE="config.settings.production"
-export DJANGO_ALLOWED_HOSTS="127.0.0.1"
-export DJANGO_SECRET_KEY="SECRET_KEY"
 export DATABASE_URL="sqlite:///django.db"
+export DJANGO_ALLOWED_HOSTS="127.0.0.1"
+export DEVELOPMENT_MODE=True
 
 # Tag traces with HTTP headers to benchmark the related code
 export DD_TRACE_HEADER_TAGS="User-Agent:http.user_agent,Referer:http.referer,Content-Type:http.content_type,Etag:http.etag"
 
-# Baseline
-pushd ${PREFIX}/trace-examples/python/django/django-simple
-    gunicorn config.wsgi --pid ${PREFIX}/gunicorn.pid > /dev/null &
-    echo "Done"
-popd
-profile_with_load "baseline"
-kill $(cat ${PREFIX}/gunicorn.pid)
-
-pushd ${PREFIX}/trace-examples/python/django/django-simple
-    ddtrace-run gunicorn config.wsgi --pid ${PREFIX}/gunicorn.pid > /dev/null &
-popd
-profile_with_load "head"
-kill $(cat ${PREFIX}/gunicorn.pid)
-
-sudo chown -R $(id -u):$(id -g) ${PREFIX}/artifacts/*
-
-echo -n "Converting MOJO to Austin ... "
-mojo2austin ${PREFIX}/artifacts/head.mojo     ${PREFIX}/artifacts/head.austin.tmp
-mojo2austin ${PREFIX}/artifacts/baseline.mojo ${PREFIX}/artifacts/baseline.austin.tmp
-echo "[done]"
-
-echo -n "Diffing ... "
-python scripts/diff.py \
-    ${PREFIX}/artifacts/head.austin.tmp \
-    ${PREFIX}/artifacts/baseline.austin.tmp \
-    ${PREFIX}/artifacts/baseline_head.diff
-echo "[done]"
-
-rm ${PREFIX}/artifacts/*.austin.tmp
-
-head -n 25 ${PREFIX}/artifacts/baseline_head.diff.top
+
+function run_scenario {
+    scenario=${1}
+
+    echo "Running scenario ${scenario}"
+
+    # Baseline
+    pushd ${PREFIX}/trace-examples/python/django/sample-django
+        uwsgi --http :8080 --enable-threads --module mysite.wsgi --pidfile ${PREFIX}/uwsgi.pid 2> /dev/null &
+        echo "Done"
+    popd
+    profile_with_load "baseline" ${scenario}
+    echo "Stopping uwsgi"
+    uwsgi --stop ${PREFIX}/uwsgi.pid
+    pkill -9 -f uwsgi || true
+
+    pushd ${PREFIX}/trace-examples/python/django/sample-django
+        uwsgi --http :8080 --enable-threads --module mysite.wsgi --pidfile ${PREFIX}/uwsgi.pid --import=ddtrace.bootstrap.sitecustomize 2> /dev/null &
+    popd
+    profile_with_load "head" ${scenario}
+    echo "Stopping uwsgi"
+    uwsgi --stop ${PREFIX}/uwsgi.pid
+    pkill -9 -f uwsgi || true
+
+    sudo chown -R $(id -u):$(id -g) ${PREFIX}/artifacts/*
+
+    echo -n "Converting MOJO to Austin ... "
+    mojo2austin ${PREFIX}/artifacts/${scenario}_head.mojo     ${PREFIX}/artifacts/${scenario}_head.austin.tmp
+    mojo2austin ${PREFIX}/artifacts/${scenario}_baseline.mojo ${PREFIX}/artifacts/${scenario}_baseline.austin.tmp
+    echo "[done]"
+
+    echo -n "Diffing ... "
+    python scripts/diff.py \
+        ${PREFIX}/artifacts/${scenario}_head.austin.tmp \
+        ${PREFIX}/artifacts/${scenario}_baseline.austin.tmp \
+        ${PREFIX}/artifacts/${scenario}_baseline_head.diff
+    echo "[done]"
+
+    rm ${PREFIX}/artifacts/*.austin.tmp
+
+    head -n 25 ${PREFIX}/artifacts/${scenario}_baseline_head.diff.top
+}
+
+
+run_scenario "load"
+run_scenario "exc"

scripts/profiles/django-simple/setup.sh

@@ -6,9 +6,7 @@ PREFIX=${1}
 AUSTIN_VERSION="3.6"
 K6_VERSION="0.26.2"
 
-export DJANGO_SETTINGS_MODULE="config.settings.production"
 export DJANGO_ALLOWED_HOSTS="127.0.0.1"
-export DJANGO_SECRET_KEY="SECRET_KEY"
 export DATABASE_URL="sqlite:///django.db"
 
 # Clean up existing installation
@@ -26,12 +24,12 @@ source ${PREFIX}/bin/activate
 pip install pip --upgrade
 
 # Install the application
-git clone https://github.com/DataDog/trace-examples.git ${PREFIX}/trace-examples
+test -d ${PREFIX}/trace-examples || git clone -b sample-django --single-branch https://github.com/DataDog/trace-examples.git ${PREFIX}/trace-examples
 pushd ${PREFIX}/trace-examples/
-    git checkout origin/django-simple
-    pushd python/django/django-simple
-        pip install -r requirements/production.txt
+    pushd python/django/sample-django
+        pip install -r requirements.txt
         python manage.py migrate
+        python manage.py collectstatic
     popd
 popd