Flask&Pillow&Docker

app.py

from flask import Flask, make_response
from PIL import Image
from io import BytesIO

app = Flask(__name__)


@app.route('/')
def index():
    return 'Hello, World!'


@app.route("/image")
@app.route('/image/<int:width>/<int:height>')
@app.route('/image/<int:width>/<int:height>/<string:color>')
@app.route('/image/<int:width>/<int:height>/<string:color>.<string:format>')
def image(width=100, height=100, color="RED", format="png"):
    im = Image.new("RGBA", (width, height), color)
    if format.upper() == "JPG":
        format = "JPEG"
    f = BytesIO()
    print(Image.SAVE.keys())
    im.save(f, format=format)
    resp = make_response(f.getvalue())
    resp.headers["content-type"] = f"image/{format}"
    return resp

Dockerfile

FROM python:3.8.1-slim

ADD ./requirements.txt /tmp/requirements.txt
RUN set -xe \
    && pip install -i https://mirrors.aliyun.com/pypi/simple --no-cache -r /tmp/requirements.txt

ADD app.py /code/app.py
WORKDIR /code
CMD ["gunicorn", "-w4", "-b0.0.0.0:8000", "app:app"]

requirements.txt

Click==7.0
Flask==1.1.1
gunicorn==20.0.4
itsdangerous==1.1.0
Jinja2==2.11.1
MarkupSafe==1.1.1
Pillow==7.0.0
Werkzeug==1.0.0