part 1

Author: mjhea0

.env/.dev-sample

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+FLASK_ENV=development
+FLACK_CONFIG=development
+DATABASE_URL=postgresql://flask_celery:flask_celery@db/flask_celery
+SECRET_KEY=my_precious
+CELERY_BROKER_URL=redis://redis:6379/0
+CELERY_RESULT_BACKEND=redis://redis:6379/0
+SOCKETIO_MESSAGE_QUEUE=redis://redis:6379/0

.gitignore

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+celerybeat.pid
+.DS_Store
+__pycache__

app.py

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+import eventlet
+eventlet.monkey_patch()
+
+from project import create_app, ext_celery, socketio
+
+app = create_app()
+
+
+@app.route("/")
+def hello_world():
+    return "Hello, World!"
+
+
+if __name__ == '__main__':
+    socketio.run(
+        app,
+        debug=True,
+        use_reloader=True,
+        host='0.0.0.0'
+    )

celery_app.py

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+from project import create_app, ext_celery
+
+
+app = create_app()
+celery = ext_celery.celery
+
+
+@app.cli.command("celery_worker")
+def celery_worker():
+    from watchgod import run_process
+    import subprocess
+
+    def run_worker():
+        subprocess.call(
+            ['celery', 'worker', '-A', 'celery_app.celery', '--loglevel=info', '-Q', 'high_priority,default']
+        )
+
+    run_process('./project', run_worker)

celerybeat-schedule

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+FROM python:3.9-slim-buster
+
+ENV PYTHONUNBUFFERED 1
+ENV PYTHONDONTWRITEBYTECODE 1
+
+RUN apt-get update \
+  # dependencies for building Python packages
+  && apt-get install -y build-essential \
+  # psycopg2 dependencies
+  && apt-get install -y libpq-dev \
+  # Additional dependencies
+  && apt-get install -y telnet netcat \
+  # cleaning up unused files
+  && apt-get purge -y --auto-remove -o APT::AutoRemove::RecommendsImportant=false \
+  && rm -rf /var/lib/apt/lists/*
+
+# Requirements are installed here to ensure they will be cached.
+COPY ./requirements.txt /requirements.txt
+RUN pip install -r /requirements.txt
+
+COPY ./compose/local/flask/entrypoint /entrypoint
+RUN sed -i 's/\r$//g' /entrypoint
+RUN chmod +x /entrypoint
+
+COPY ./compose/local/flask/start /start
+RUN sed -i 's/\r$//g' /start
+RUN chmod +x /start
+
+COPY ./compose/local/flask/celery/worker/start /start-celeryworker
+RUN sed -i 's/\r$//g' /start-celeryworker
+RUN chmod +x /start-celeryworker
+
+COPY ./compose/local/flask/celery/beat/start /start-celerybeat
+RUN sed -i 's/\r$//g' /start-celerybeat
+RUN chmod +x /start-celerybeat
+
+COPY ./compose/local/flask/celery/flower/start /start-flower
+RUN sed -i 's/\r$//g' /start-flower
+RUN chmod +x /start-flower
+
+WORKDIR /app
+
+ENTRYPOINT ["/entrypoint"]

compose/local/flask/Dockerfile

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+#!/bin/bash
+
+set -o errexit
+set -o nounset
+
+rm -f './celerybeat.pid'
+celery beat -A celery_app.celery -l info

compose/local/flask/celery/beat/start

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+#!/bin/bash
+
+set -o errexit
+set -o nounset
+
+worker_ready() {
+    celery -A celery_app.celery inspect ping
+}
+
+until worker_ready; do
+  >&2 echo 'Celery workers not available'
+  sleep 1
+done
+>&2 echo 'Celery workers is available'
+
+flower \
+    --app=celery_app.celery \
+    --broker="${CELERY_BROKER_URL}"

compose/local/flask/celery/flower/start

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+#!/bin/bash
+
+set -o errexit
+set -o nounset
+
+# celery worker -A app.celery --loglevel=info
+flask celery_worker

compose/local/flask/celery/worker/start

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+#!/bin/bash
+
+# if any of the commands in your code fails for any reason, the entire script fails
+set -o errexit
+# fail exit if one of your pipe command fails
+set -o pipefail
+# exits if any of your variables is not set
+set -o nounset
+
+postgres_ready() {
+python << END
+import sys
+
+import psycopg2
+import urllib.parse as urlparse
+import os
+
+url = urlparse.urlparse(os.environ['DATABASE_URL'])
+dbname = url.path[1:]
+user = url.username
+password = url.password
+host = url.hostname
+port = url.port
+
+try:
+    psycopg2.connect(
+        dbname=dbname,
+        user=user,
+        password=password,
+        host=host,
+        port=port
+    )
+except psycopg2.OperationalError:
+    sys.exit(-1)
+sys.exit(0)
+
+END
+}
+until postgres_ready; do
+  >&2 echo 'Waiting for PostgreSQL to become available...'
+  sleep 1
+done
+>&2 echo 'PostgreSQL is available'
+
+exec "$@"

compose/local/flask/entrypoint

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+#!/bin/bash
+
+set -o errexit
+set -o pipefail
+set -o nounset
+
+flask db upgrade
+# flask run --host=0.0.0.0
+python app.py

compose/local/flask/start

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+version: '3.8'
+
+services:
+  web:
+    build:
+      context: .
+      dockerfile: ./compose/local/flask/Dockerfile
+    image: flask_celery_example_web
+    # '/start' is the shell script used to run the service
+    command: /start
+    # this volume is used to map the files and folders on the host to the container
+    # so if we change code on the host, code in the docker container will also be changed
+    volumes:
+      - .:/app
+    ports:
+      - 5010:5000
+    env_file:
+      - .env/.dev-sample
+    environment:
+      - FLASK_APP=app
+    depends_on:
+      - redis
+      - db
+
+  db:
+    image: postgres:13-alpine
+    volumes:
+      - postgres_data:/var/lib/postgresql/data/
+    environment:
+      - POSTGRES_DB=flask_celery
+      - POSTGRES_USER=flask_celery
+      - POSTGRES_PASSWORD=flask_celery
+
+  redis:
+    image: redis:6-alpine
+
+  celery_worker:
+    build:
+      context: .
+      dockerfile: ./compose/local/flask/Dockerfile
+    image: flask_celery_example_celery_worker
+    command: /start-celeryworker
+    volumes:
+      - .:/app
+    env_file:
+      - .env/.dev-sample
+    environment:
+      - FLASK_APP=celery_app
+    depends_on:
+      - redis
+      - db
+
+  celery_beat:
+    build:
+      context: .
+      dockerfile: ./compose/local/flask/Dockerfile
+    image: flask_celery_example_celery_beat
+    command: /start-celerybeat
+    volumes:
+      - .:/app
+    env_file:
+      - .env/.dev-sample
+    environment:
+      - FLASK_APP=celery_app
+    depends_on:
+      - redis
+      - db
+
+  flower:
+    build:
+      context: .
+      dockerfile: ./compose/local/flask/Dockerfile
+    image: flask_celery_example_celey_flower
+    command: /start-flower
+    volumes:
+      - .:/app
+    env_file:
+      - .env/.dev-sample
+    environment:
+      - FLASK_APP=celery_app
+    ports:
+      - 5557:5555
+    depends_on:
+      - redis
+      - db
+
+volumes:
+  postgres_data:

docker-compose.yml

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+Generic single-database configuration.

migrations/README

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+# A generic, single database configuration.
+
+[alembic]
+# template used to generate migration files
+# file_template = %%(rev)s_%%(slug)s
+
+# set to 'true' to run the environment during
+# the 'revision' command, regardless of autogenerate
+# revision_environment = false
+
+
+# Logging configuration
+[loggers]
+keys = root,sqlalchemy,alembic,flask_migrate
+
+[handlers]
+keys = console
+
+[formatters]
+keys = generic
+
+[logger_root]
+level = WARN
+handlers = console
+qualname =
+
+[logger_sqlalchemy]
+level = WARN
+handlers =
+qualname = sqlalchemy.engine
+
+[logger_alembic]
+level = INFO
+handlers =
+qualname = alembic
+
+[logger_flask_migrate]
+level = INFO
+handlers =
+qualname = flask_migrate
+
+[handler_console]
+class = StreamHandler
+args = (sys.stderr,)
+level = NOTSET
+formatter = generic
+
+[formatter_generic]
+format = %(levelname)-5.5s [%(name)s] %(message)s
+datefmt = %H:%M:%S