Add compose samples from docs (docker#305)

Signed-off-by: Stefan Scherer <[email protected]>

Signed-off-by: Stefan Scherer <[email protected]>

Author: StefanScherer

README.md

@@ -109,6 +109,11 @@ To stop and remove all containers of the sample application run:
 ```console
 docker compose down
 ```
+
+### Quickstart guides
+
+In addition to all the ready to run Compose samples listed above the folder [official-documentation-samples](official-documentation-samples/README.md) contains quickstart guides. Each of these step by step guides explain which files need to be created to build and run a Docker Compose application.
+
 <!--lint disable awesome-toc-->
 ## Contribute
 

official-documentation-samples/README.md

@@ -0,0 +1,28 @@
+# Sample apps with Compose
+
+The following samples show the various aspects of how to work with Docker
+Compose. As a prerequisite, be sure to [install Docker Compose](https://docs.docker.com/compose/install/)
+if you have not already done so.
+
+## Key concepts these samples cover
+
+The samples should help you to:
+
+- define services based on Docker images using
+  [Compose files](https://docs.docker.com/compose/compose-file/) `docker-compose.yml` files
+- understand the relationship between `docker-compose.yml` and
+  [Dockerfiles](https://docs.docker.com/engine/reference/builder/)
+- learn how to make calls to your application services from Compose files
+
+## Samples tailored to demo Compose
+
+These samples focus specifically on Docker Compose:
+
+- [Quickstart: Compose and Django](./django/README.md) - Shows how to use Docker Compose to set up and run a simple Django/PostgreSQL app.
+
+- [Quickstart: Compose and Rails](./rails/README.md) - Shows how to use
+Docker Compose to set up and run a Rails/PostgreSQL app.
+
+- [Quickstart: Compose and WordPress](./wordpress/README.md) - Shows how to
+use Docker Compose to set up and run WordPress in an isolated environment
+with Docker containers.

official-documentation-samples/django/README.md

@@ -0,0 +1,286 @@
+# Quickstart: Compose and Django
+
+This quick-start guide demonstrates how to use Docker Compose to set up and run a simple Django/PostgreSQL app. Before starting,
+[install Compose](https://docs.docker.com/compose/install/).
+
+## Define the project components
+
+For this project, you need to create a Dockerfile, a Python dependencies file,
+and a `docker-compose.yml` file. (You can use either a `.yml` or `.yaml` extension for this file.)
+
+1. Create an empty project directory.
+
+    You can name the directory something easy for you to remember. This directory is the context for your application image. The directory should only contain resources to build that image.
+
+2. Create a new file called `Dockerfile` in your project directory.
+
+    The Dockerfile defines an application's image content via one or more build
+    commands that configure that image. Once built, you can run the image in a
+    container.  For more information on `Dockerfile`, see the [Docker user guide](https://docs.docker.com/get-started/)
+    and the [Dockerfile reference](https://docs.docker.com/engine/reference/builder/).
+
+3. Add the following content to the `Dockerfile`.
+
+   ```dockerfile
+   # syntax=docker/dockerfile:1
+   FROM python:3
+   ENV PYTHONDONTWRITEBYTECODE=1
+   ENV PYTHONUNBUFFERED=1
+   WORKDIR /code
+   COPY requirements.txt /code/
+   RUN pip install -r requirements.txt
+   COPY . /code/
+   ```
+
+   This `Dockerfile` starts with a [Python 3 parent image](https://hub.docker.com/r/library/python/tags/3/).
+   The parent image is modified by adding a new `code` directory. The parent image is further modified
+   by installing the Python requirements defined in the `requirements.txt` file.
+
+4. Save and close the `Dockerfile`.
+
+5. Create a `requirements.txt` in your project directory.
+
+    This file is used by the `RUN pip install -r requirements.txt` command in your `Dockerfile`.
+
+6. Add the required software in the file.
+
+    ```python
+    Django>=3.0,<4.0
+    psycopg2>=2.8
+    ```
+
+7. Save and close the `requirements.txt` file.
+
+8. Create a file called `docker-compose.yml` in your project directory.
+
+    The `docker-compose.yml` file describes the services that make your app. In
+    this example those services are a web server and database.  The compose file
+    also describes which Docker images these services use, how they link
+    together, any volumes they might need to be mounted inside the containers.
+    Finally, the `docker-compose.yml` file describes which ports these services
+    expose. See the [`docker-compose.yml` reference](https://docs.docker.com/compose/compose-file/) for more
+    information on how this file works.
+
+9. Add the following configuration to the file.
+
+   ```yaml
+   services:
+     db:
+       image: postgres
+       volumes:
+         - ./data/db:/var/lib/postgresql/data
+       environment:
+         - POSTGRES_DB=postgres
+         - POSTGRES_USER=postgres
+         - POSTGRES_PASSWORD=postgres
+     web:
+       build: .
+       command: python manage.py runserver 0.0.0.0:8000
+       volumes:
+         - .:/code
+       ports:
+         - "8000:8000"
+       environment:
+         - POSTGRES_NAME=postgres
+         - POSTGRES_USER=postgres
+         - POSTGRES_PASSWORD=postgres
+       depends_on:
+         - db
+   ```
+
+   This file defines two services: The `db` service and the `web` service.
+
+   > Note:
+   >
+   > This uses the build in development server to run your application
+   > on port 8000. Do not use this in a production environment. For more
+   > information, see [Django documentation](https://docs.djangoproject.com/en/3.1/intro/tutorial01/#the-development-server){: target="_blank" rel="noopener" class="_”}.
+
+10. Save and close the `docker-compose.yml` file.
+
+## Create a Django project
+
+In this step, you create a Django starter project by building the image from the build context defined in the previous procedure.
+
+1. Change to the root of your project directory.
+
+2. Create the Django project by running the [docker compose run](https://docs.docker.com/engine/reference/commandline/compose_run/)
+   command as follows.
+
+   ```console
+   sudo docker compose run web django-admin startproject composeexample .
+   ```
+
+   This instructs Compose to run `django-admin startproject composeexample`
+   in a container, using the `web` service's image and configuration. Because
+   the `web` image doesn't exist yet, Compose builds it from the current
+   directory, as specified by the `build: .` line in `docker-compose.yml`.
+
+   Once the `web` service image is built, Compose runs it and executes the
+   `django-admin startproject` command in the container. This command
+   instructs Django to create a set of files and directories representing a
+   Django project.
+
+3. After the `docker compose` command completes, list the contents of your project.
+
+   ```console
+   $ ls -l
+
+   drwxr-xr-x 2 root   root   composeexample
+   drwxr-xr-x 3 root   root   data
+   -rw-rw-r-- 1 user   user   docker-compose.yml
+   -rw-rw-r-- 1 user   user   Dockerfile
+   -rwxr-xr-x 1 root   root   manage.py
+   -rw-rw-r-- 1 user   user   requirements.txt
+   ```
+
+   If you are running Docker on Linux, the files `django-admin` created are
+   owned by root. This happens because the container runs as the root user.
+   Change the ownership of the new files.
+
+   Do not change the permission of the data folder where Postgres has its file, otherwise Postgres will not be able to start due to permission issues.
+
+   ```console
+   sudo chown -R $USER:$USER composeexample manage.py
+   ```
+
+   If you are running Docker on Mac or Windows, you should already
+   have ownership of all files, including those generated by
+   `django-admin`. List the files just to verify this.
+
+   ```console
+   $ ls -l
+
+   total 32
+   -rw-r--r--  1 user  staff  145 Feb 13 23:00 Dockerfile
+   drwxr-xr-x  6 user  staff  204 Feb 13 23:07 composeexample
+   -rw-r--r--  1 user  staff  159 Feb 13 23:02 docker-compose.yml
+   -rwxr-xr-x  1 user  staff  257 Feb 13 23:07 manage.py
+   -rw-r--r--  1 user  staff   16 Feb 13 23:01 requirements.txt
+   ```
+
+### Connect the database
+
+In this section, you set up the database connection for Django.
+
+1. In your project directory, edit the `composeexample/settings.py` file.
+
+2. Replace the `DATABASES = ...` with the following:
+
+   ```python
+   # settings.py
+   
+   import os
+   
+   [...]
+   
+   DATABASES = {
+       'default': {
+           'ENGINE': 'django.db.backends.postgresql',
+           'NAME': os.environ.get('POSTGRES_NAME'),
+           'USER': os.environ.get('POSTGRES_USER'),
+           'PASSWORD': os.environ.get('POSTGRES_PASSWORD'),
+           'HOST': 'db',
+           'PORT': 5432,
+       }
+   }
+   ```
+
+   These settings are determined by the
+   [postgres](https://hub.docker.com/_/postgres) Docker image
+   specified in `docker-compose.yml`.
+
+3. Save and close the file.
+
+4. Run the [docker compose up](https://docs.docker.com/engine/reference/commandline/compose_up/) command from the top level directory for your project.
+
+   ```console
+   $ docker compose up
+
+   djangosample_db_1 is up-to-date
+   Creating djangosample_web_1 ...
+   Creating djangosample_web_1 ... done
+   Attaching to djangosample_db_1, djangosample_web_1
+   db_1   | The files belonging to this database system will be owned by user "postgres".
+   db_1   | This user must also own the server process.
+   db_1   |
+   db_1   | The database cluster will be initialized with locale "en_US.utf8".
+   db_1   | The default database encoding has accordingly been set to "UTF8".
+   db_1   | The default text search configuration will be set to "english".
+
+   <...>
+
+   web_1  | July 30, 2020 - 18:35:38
+   web_1  | Django version 3.0.8, using settings 'composeexample.settings'
+   web_1  | Starting development server at http://0.0.0.0:8000/
+   web_1  | Quit the server with CONTROL-C.
+   ```
+
+   At this point, your Django app should be running at port `8000` on
+   your Docker host. On Docker Desktop for Mac and Docker Desktop for Windows, go
+   to `http://localhost:8000` on a web browser to see the Django
+   welcome page.
+
+   ![Django example](images/django-it-worked.png)
+
+   > Note:
+   >
+   > On certain platforms (Windows 10), you might need to edit `ALLOWED_HOSTS`
+   > inside `settings.py` and add your Docker host name or IP address to the list.
+   > For demo purposes, you can set the value to:
+   >
+   > ```python
+   > ALLOWED_HOSTS = ['*']
+   > ```
+   >
+   > This value is **not** safe for production usage.  Refer to the
+   > [Django documentation](https://docs.djangoproject.com/en/1.11/ref/settings/#allowed-hosts)  for more information.
+
+5. List running containers.
+
+   In another terminal window, list the running Docker processes with the `docker ps` or `docker container ls` command.
+
+   ```console
+   $ docker ps
+
+   CONTAINER ID  IMAGE       COMMAND                  CREATED         STATUS        PORTS                    NAMES
+   def85eff5f51  django_web  "python3 manage.py..."   10 minutes ago  Up 9 minutes  0.0.0.0:8000->8000/tcp   django_web_1
+   678ce61c79cc  postgres    "docker-entrypoint..."   20 minutes ago  Up 9 minutes  5432/tcp                 django_db_1
+   ```
+
+6. Shut down services and clean up by using either of these methods:
+
+    * Stop the application by typing `Ctrl-C`  in the same shell in where you
+      started it:
+
+      ```console
+      Gracefully stopping... (press Ctrl+C again to force)
+      Killing test_web_1 ... done
+      Killing test_db_1 ... done
+      ```
+
+    * Or, for a more elegant shutdown, switch to a different shell, and run
+      [docker compose down](https://docs.docker.com/engine/reference/commandline/compose_down/) from the top level of your
+      Django sample project directory.
+
+      ```console
+      $ docker compose down
+
+      Stopping django_web_1 ... done
+      Stopping django_db_1 ... done
+      Removing django_web_1 ... done
+      Removing django_web_run_1 ... done
+      Removing django_db_1 ... done
+      Removing network django_default
+      ```
+
+  Once you've shut down the app, you can safely remove the Django project directory (for example, `rm -rf django`).
+
+## More Compose documentation
+
+* [Docker Compose overview](https://docs.docker.com/compose/)
+* [Install Docker Compose](https://docs.docker.com/compose/install/)
+* [Getting Started with Docker Compose](https://docs.docker.com/compose/gettingstarted/)
+* [Docker Compose Command line reference](https://docs.docker.com/compose/reference/)
+* [Compose file reference](https://docs.docker.com/compose/compose-file/)
+* [Awesome Compose Django sample application](../../django/README.md)