Replacing Flask with Gunicorn

You can replace Flask with Gunicorn as an alternative HTTP server. Create a simple Hello World app to learn how.

Prerequisites

• QRadar app SDK version 2
• Python 3
• pip

Create the app

Create a new folder for your app:

mkdir GunicornApp && cd GunicornApp

Use the QRadar app SDK to initialise the app code:

qapp create

Add the Gunicorn pip Dependency

Create a new folder called container/pip for storing the Gunicorn pip dependencies that are installed.

mkdir container/pip

Download the Gunicorn pip and any of its dependencies by using pip download:

pip download                \
    --only-binary=:all:     \
    --platform linux_x86_64 \
    --dest container/pip    \
    gunicorn

This code downloads the Gunicorn pip and any of its dependencies into the container/pip folder.

Add the Supervisord configuration

Create a new folder called container/conf/supervisord.d to hold supervisord configuration files:

mkdir -p container/conf/supervisord.d

This container/conf/supervisord.d folder holds all Supervisord configurations, which are copied into /etc/supervisord.d on startup.

Create a Gunicorn configuration file container/conf/supervisord.d/gunicorn.conf for your app:

[program:gunicorn]
directory=/opt/app-root
command=/usr/local/bin/gunicorn -b 0.0.0.0:5000 --timeout 120 --access-logfile - --workers=4 --preload "app:create_app()"
autostart=true
autorestart=unexpected
stdout_logfile=/opt/app-root/store/log/gunicorn.log
stderr_logfile=/opt/app-root/store/log/gunicorn.log

This configuration file defines how Supervisord should run Gunicorn as part of this app, with log files defined, automatic restarts and the command to start Gunicorn (with all of its command line parameters) stated.

Write the manifest

Edit the manifest.json file to edit some values to make it more relevant to the app.

Example:

{
  "name": "Gunicorn App",
  "description": "Custom supervisord configuration which starts gunicorn as a replacement for flask and exposes port 5000 as the webserver port",
  "version": "1.0.0",
  "image": "qradar-app-base:2.0.0",
  "load_flask": "false",
  "areas": [
    {
      "id": "GunicornSupervisordTab",
      "text": "Gunicorn supervisord",
      "description": "Dummy tab that displays text from the flask app",
      "url": "index",
      "required_capabilities": []
    }
  ],
  "services": [
    {
      "name": "gunicorn",
      "port": 5000,
      "version": "1.0"
    }
  ],
  "uuid": "<your unique app UUID>"
}

This manifest code overrides the Flask webserver and informs QRadar that it should not be loaded:

"load_flask": "false",

The manifest then defines an area in the QRadar UI to display the app, called GunicornSupervisordTab that is populated by calling the /index endpoint:

"areas": [
  {
    "id": "GunicornSupervisordTab",
    "text": "Gunicorn supervisord",
    "description": "Dummy tab that displays text from the flask app",
    "url": "index",
    "required_capabilities": []
  }
],

Finally, the manifest describes and defines a named service that will run the Supervisord gunicorn program that you configured previously, along with the port it serves on, exposing the path /index:

"services": [
  {
    "name": "gunicorn",
    "port": 5000,
    "version": "1.0"
  }
],

Because this named service is running on port 5000, the area does not need to include a reference to the named service that it is querying; it can be accessed directly. This is only the case if the named service is running on port 5000.

Run and package the app

Use the following command to run the app locally from the project root:

qapp run

Use the following commands to package and deploy the app

qapp package -p <app zip name>

qapp deploy -p <app zip name> -q <qradar console> -u <qradar user>