Make defang environment dynamic based on stack input

Author: lionello

README.md

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+# Python & Flask & AWS S3
+
+[![1-click-deploy](https://raw.githubusercontent.com/DefangLabs/defang-assets/main/Logos/Buttons/SVG/deploy-with-defang.svg)](https://portal.defang.dev/redirect?url=https%3A%2F%2Fgithub.com%2Fnew%3Ftemplate_name%3Dsample-python-s3-template%26template_owner%3DDefangSamples)
+
+This sample requires an API key to access AWS S3. The name of the config values is referenced in the compose.yaml file.
+To provide a value for it, you can use the Defang CLI like this:
+
+```
+defang config set --name AWS_ACCESS_KEY
+defang config set --name AWS_SECRET_KEY
+```
+
+and then enter the value when prompted.
+
+## Testing
+
+```bash
+curl -X POST -H 'Content-Type: application/json' -d '{ "first_name" : "jane", "last_name" : "doe" }' https://xxxxxx/upload
+curl https://xxxxxx/download
+```
+
+---
+
+Title: Python & Flask & AWS S3
+
+Short Description: An app that demonstrates how to upload and download files from AWS S3 using Python and Flask.
+
+Tags: Python, Flask, AWS, S3
+
+Languages: python

app/.gitignore

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+
+# --- Python ---
+# Byte-compiled / optimized / DLL files
+__pycache__/
+*.py[cod]
+*$py.class
+
+# C extensions
+*.so
+
+# Distribution / packaging
+.Python
+build/
+develop-eggs/
+dist/
+downloads/
+eggs/
+.eggs/
+lib/
+lib64/
+parts/
+sdist/
+var/
+wheels/
+share/python-wheels/
+*.egg-info/
+.installed.cfg
+*.egg
+MANIFEST
+
+# PyInstaller
+*.manifest
+*.spec
+
+# Installer logs
+pip-log.txt
+pip-delete-this-directory.txt
+
+# Unit test / coverage reports
+htmlcov/
+.tox/
+.nox/
+.coverage
+.coverage.*
+.cache
+nosetests.xml
+coverage.xml
+*.cover
+*.py,cover
+.hypothesis/
+.pytest_cache/
+cover/
+
+# Translations
+*.mo
+*.pot
+
+# Django stuff:
+*.log
+local_settings.py
+db.sqlite3
+db.sqlite3-journal
+
+# Flask stuff:
+instance/
+.webassets-cache
+
+# Scrapy stuff:
+.scrapy
+
+# Sphinx documentation
+docs/_build/
+
+# PyBuilder
+.pybuilder/
+target/
+
+# Jupyter Notebook
+.ipynb_checkpoints
+
+# IPython
+profile_default/
+ipython_config.py
+
+# pdm
+.pdm.toml
+.pdm-python
+.pdm-build/
+
+# PEP 582
+__pypackages__/
+
+# Celery stuff
+celerybeat-schedule
+celerybeat.pid
+
+# SageMath parsed files
+*.sage.py
+
+# Environments
+.env
+.venv
+env/
+venv/
+ENV/
+env.bak/
+venv.bak/
+
+# Spyder project settings
+.spyderproject
+.spyproject
+
+# Rope project settings
+.ropeproject
+
+# mkdocs documentation
+/site
+
+# mypy
+.mypy_cache/
+.dmypy.json
+dmypy.json
+
+# Pyre type checker
+.pyre/
+
+# pytype static type analyzer
+.pytype/
+
+# Cython debug symbols
+cython_debug/
+
+# PyCharm
+.idea/

app/Dockerfile

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+# Use an official Python runtime as a parent image
+FROM python:3.11-slim
+
+# Set the working directory to /app
+WORKDIR /app
+
+# Install required C++11 libraries and ca-certificates
+RUN apt-get update -qq \
+      && apt-get install -y \
+      build-essential \
+      python3-dev \
+      ca-certificates \
+      curl \
+      && apt-get clean \
+      && rm -rf /var/lib/apt/lists/*
+
+# Install any needed packages specified in requirements.txt
+COPY requirements.txt /app/
+RUN pip install --no-cache-dir -r requirements.txt
+
+# Copy the current directory contents into the container at /app
+COPY . /app
+
+# Make port 5000 available to the world outside this container
+EXPOSE 5000
+
+# Run main when the container launches
+ENTRYPOINT ["uwsgi", "--http", "0.0.0.0:5000", "--master", "-p", "2", "-w", "main:app"]
+USER nobody

app/main.py

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+import os
+import json
+import boto3
+from botocore.exceptions import ClientError
+
+from flask import Flask
+from flask import request
+
+
+app = Flask(__name__)
+
+
+REGION_NAME = 'us-west-2'
+BUCKET_NAME = 'my-sample-bucket'
+FILE_NAME   = 'file1.json'
+
+
+@app.route("/")
+def index():
+    return { 'status' : 'ok' }, 200
+
+
+@app.route("/upload", methods=['POST'])
+def upload():
+    # Check that the post body is valid JSON
+    if not request.is_json:
+        return { 'error': 'Invalid JSON' }, 400
+
+    # Parse the JSON into a Python dictionary
+    data = request.get_json()
+
+    AWS_ACCESS_KEY=os.environ['AWS_ACCESS_KEY']
+    AWS_SECRET_KEY=os.environ['AWS_SECRET_KEY']
+
+    # Write the JSON to S3
+    s3 = boto3.client('s3', region_name=REGION_NAME, aws_access_key_id=AWS_ACCESS_KEY, aws_secret_access_key=AWS_SECRET_KEY)
+
+    with open(FILE_NAME, 'w') as f:
+        json.dump(data, f)
+
+    s3.upload_file(FILE_NAME, BUCKET_NAME, FILE_NAME)
+
+    return { 'status': 'ok' }, 200
+
+
+@app.route("/download", methods=['GET'])
+def download():
+    AWS_ACCESS_KEY=os.environ['AWS_ACCESS_KEY']
+    AWS_SECRET_KEY=os.environ['AWS_SECRET_KEY']
+
+    # Write the JSON to S3
+    s3 = boto3.client('s3', region_name=REGION_NAME, aws_access_key_id=AWS_ACCESS_KEY, aws_secret_access_key=AWS_SECRET_KEY)
+
+    try:
+        file_object = s3.get_object(Bucket=BUCKET_NAME, Key=FILE_NAME)
+        # Read the Body stream of the S3 object and load the JSON
+        file_content = json.load(file_object['Body'])
+
+        return file_content, 200
+    except ClientError as e:
+        error_code = int(e.response['Error']['Code'])
+        if error_code == 404:
+            return { 'error': 'File not found in S3 bucket' }, 404
+        else:
+            return { 'error': 'Unknown error' }, 500
+
+
+if __name__ == '__main__':
+    app.run(debug=True, host='0.0.0.0')
+

app/requirements.txt

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+uwsgi
+flask
+boto3

compose.yaml

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+name: python-s3
+services:
+  app:
+    restart: unless-stopped
+    build:
+      context: ./app
+      dockerfile: Dockerfile
+    ports:
+      - mode: ingress
+        target: 5000
+    environment:
+      - AWS_ACCESS_KEY
+      - AWS_SECRET_KEY
+    deploy:
+      resources:
+        reservations:
+          memory: 256M
+    healthcheck:
+      test:
+        - CMD
+        - curl
+        - -f
+        - http://localhost:5000/