Deploying a Flask App to AWS Elastic Beanstalk with CDK and With the AWS Console

Mon, 27 Feb 2023 14:40:39 +0000

Steps in CDK

Initialize construct
Zip flask code
Set up options for application, env vars, and app version
Set environment
Make sure environment is built after CDK application

## Deploy to ElasticBeanstalkanstalk-application-packaging-through-cdk-in-typescript-e91b7ffe4928
app_name = "MyApp"
elb_flask_app = elb.CfnApplication(
    self, f"flask-appserver", application_name=app_name
)

## Move app code into S3 for ELB
elb_archive = s3_assets.Asset(
    self,
    f"elb-flask-app-{stage}",
    path=f"{str(Path(__file__).absolute().parents[2])}/app.zip",
)

## Set OptionSettingProperties
option_setting_properties = [
    elb.CfnEnvironment.OptionSettingProperty(
        namespace="aws:autoscaling:launchconfiguration",
        option_name="InstanceType",
        value="t3.small",
    ),
    elb.CfnEnvironment.OptionSettingProperty(
        namespace="aws:autoscaling:launchconfiguration",
        option_name="IamInstanceProfile",
        value="aws-elasticbeanstalk-ec2-role",
    ),
    elb.CfnEnvironment.OptionSettingProperty(
        namespace="aws:autoscaling:launchconfiguration",
        option_name="IamInstanceProfile",
        value="aws-elasticbeanstalk-servicerole",
    ),
    # This is an example of setting up an environment variable
    elb.CfnEnvironment.OptionSettingProperty(
        namespace="aws:elasticbeanstalk:application:environment",
        option_name="ES_DOMAIN",
        value=es_domain.domain_endpoint,
    ),
]

## Set app version properties
app_version_props = elb.CfnApplicationVersion(
    self,
    f"AppVersion-{stage}",
    application_name=app_name,
    source_bundle=elb.CfnApplicationVersion.SourceBundleProperty(
        s3_bucket=elb_archive.s3_bucket_name,
        s3_key=elb_archive.s3_object_key,
    ),
)

## Set environment
elb_env = elb.CfnEnvironment(
    self,
    f"elb-env",
    environment_name=f"elb-env",
    application_name=app_name,
    solution_stack_name="64bit Amazon Linux 2 v3.2.1 running Python 3.8",
    option_settings=option_setting_properties,
    version_label=app_version_props.ref,
)

## Ensure the env isn't built before the app by placing this at the end of your CDK stack file
app_version_props.add_depends_on(elb_flask_app)
elb_env.add_depends_on(elb_flask_app)

Steps in AWS Console

Launch EC2 instance
SSH into it,
Set up Git keys
1. See here
2. Add deploy key to repo
Pull code from Github into instance

Run Flask server

Activate virutal environment
Install dependencies with pip install -r requirements.txt
Set environment variables:
1. FLASK_ENV=development or FLASK_ENV=prod

Set up uWSGI

Install gcc
Install uWSGI with pip install uwsgi
Install NGinx source 1. Only do steps 1 and 2 from article:

sudo apt update
sudo apt install nginx
# Test firewall
sudo ufw app list
sudo ufw allow 'Nginx HTTP'
sudo ufw status

Set up uWSGI configuration with app.ini:

[uwsgi]
module = wsgi:app
master = true
processes = 5
socket = myproject.sock
chmod-socket = 660
vacuum = true
die-on-term = true

Set up system profile file /etc/systemd/system/myproject.service, taken from linked article

[Unit]
Description=uWSGI instance to serve myproject
After=network.target

[Service]
User=sammy
Group=www-data
WorkingDirectory=/home/sammy/myproject
Environment="PATH=/home/sammy/myproject/myprojectenv/bin"
ExecStart=/home/sammy/myproject/myprojectenv/bin/uwsgi --ini myproject.ini

[Install]
WantedBy=multi-user.target

Start with systemctl:
1. sudo systemctl start myproject
2. sudo systemctl enable myproject
Set up nginx
1. Edit /etc/nginx/sites-available/myapp

server {
    listen 80;
    server_name <EC2 domain>;

    location / {
        include uwsgi_params;
        uwsgi_pass unix:/home/ubuntu/myapp/flask-app/myapp.sock;
    }
}

Then link: sudo ln -s /etc/nginx/sites-available/myproject /etc/nginx/sites-enabled
- Restart nginx service:
  - Update firewall rules
```
$ sudo ufw delete allow 5000
$ sudo ufw allow 'Nginx Full'
```

Sources

AWS - Deploying a Flask Application to Elastic Beanstalk Packaging a NodeJS application with CDK on Elastic Beanstalk

Hugo Project Architecture

Tue, 13 Sep 2022 01:34:20 +0000

Page Bundles

Personal Site Redesign Personal Site Redesign

Content Sections

Any directories within content/ define a different content section such as posts, tutorials, etc. These directories are also used to determine a page’s content type, which can affect how the page is displayed, which archetype applies, and more

Sources

Content sections source note

Flask-Tables Variable Names Must Match Fields

Thu, 01 Sep 2022 20:00:21 +0000

When setting up a table with Flask-Tables, the variable names for the columns must match those in the database the table is pulling from. Alternative column names can be passed in as a parameter.

Source

Flask-Tables Documentation

REST API Best Practices

Tue, 07 Jun 2022 15:50:53 +0000

Path vs. Request Parameters

Path parameters (/item) identify a specific resource(s), while request parameters (/item?color=blue) should act to filter items of that resource.

Sources

Path vs. Request Parameters

Web-Dev on The Edge Cases

Deploying a Flask App to AWS Elastic Beanstalk with CDK and With the AWS Console

Steps in CDK

Steps in AWS Console

Sources

Hugo Project Architecture

Page Bundles

Content Sections

Sources

Flask-Tables Variable Names Must Match Fields

Source

REST API Best Practices

Path vs. Request Parameters

Sources