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114 lines
3.5 KiB
ReStructuredText
114 lines
3.5 KiB
ReStructuredText
:title: Python Web app example
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:description: Building your own python web app using docker
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:keywords: docker, example, python, web app
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.. _python_web_app:
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Python Web App
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==============
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.. include:: example_header.inc
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The goal of this example is to show you how you can author your own
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Docker images using a parent image, making changes to it, and then
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saving the results as a new image. We will do that by making a simple
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hello Flask web application image.
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**Steps:**
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.. code-block:: bash
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sudo docker pull shykes/pybuilder
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We are downloading the ``shykes/pybuilder`` Docker image
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.. code-block:: bash
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URL=http://github.com/shykes/helloflask/archive/master.tar.gz
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We set a ``URL`` variable that points to a tarball of a simple helloflask web app
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.. code-block:: bash
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BUILD_JOB=$(sudo docker run -d -t shykes/pybuilder:latest /usr/local/bin/buildapp $URL)
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Inside of the ``shykes/pybuilder`` image there is a command called
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``buildapp``, we are running that command and passing the ``$URL`` variable
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from step 2 to it, and running the whole thing inside of a new
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container. The ``BUILD_JOB`` environment variable will be set with the new container ID.
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.. code-block:: bash
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sudo docker attach -sig-proxy=false $BUILD_JOB
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[...]
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While this container is running, we can attach to the new container to
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see what is going on. The flag ``-sig-proxy`` set as ``false`` allows you to connect and
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disconnect (Ctrl-C) to it without stopping the container.
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.. code-block:: bash
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sudo docker ps -a
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List all Docker containers. If this container has already finished
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running, it will still be listed here.
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.. code-block:: bash
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BUILD_IMG=$(sudo docker commit $BUILD_JOB _/builds/github.com/shykes/helloflask/master)
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Save the changes we just made in the container to a new image called
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``_/builds/github.com/hykes/helloflask/master`` and save the image ID in
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the ``BUILD_IMG`` variable name.
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.. code-block:: bash
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WEB_WORKER=$(sudo docker run -d -p 5000 $BUILD_IMG /usr/local/bin/runapp)
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- **"docker run -d "** run a command in a new container. We pass "-d"
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so it runs as a daemon.
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- **"-p 5000"** the web app is going to listen on this port, so it
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must be mapped from the container to the host system.
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- **"$BUILD_IMG"** is the image we want to run the command inside of.
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- **/usr/local/bin/runapp** is the command which starts the web app.
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Use the new image we just created and create a new container with
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network port 5000, and return the container ID and store in the
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``WEB_WORKER`` variable.
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.. code-block:: bash
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sudo docker logs $WEB_WORKER
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* Running on http://0.0.0.0:5000/
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View the logs for the new container using the ``WEB_WORKER`` variable, and
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if everything worked as planned you should see the line ``Running on
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http://0.0.0.0:5000/`` in the log output.
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.. code-block:: bash
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WEB_PORT=$(sudo docker port $WEB_WORKER 5000 | awk -F: '{ print $2 }')
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Look up the public-facing port which is NAT-ed. Find the private port
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used by the container and store it inside of the ``WEB_PORT`` variable.
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.. code-block:: bash
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# install curl if necessary, then ...
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curl http://127.0.0.1:$WEB_PORT
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Hello world!
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Access the web app using the ``curl`` binary. If everything worked as planned you
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should see the line ``Hello world!`` inside of your console.
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**Video:**
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See the example in action
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.. raw:: html
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<div style="margin-top:10px;">
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<iframe width="720" height="350" src="http://ascii.io/a/2573/raw" frameborder="0"></iframe>
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</div>
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Continue to :ref:`running_ssh_service`.
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