diff --git a/docs/sources/examples/index.rst b/docs/sources/examples/index.rst index cd08107e7a..cf9ed9340a 100644 --- a/docs/sources/examples/index.rst +++ b/docs/sources/examples/index.rst @@ -16,7 +16,6 @@ to more substantial services like those which you might find in production. :maxdepth: 1 hello_world - python_web_app nodejs_web_app running_redis_service running_ssh_service @@ -26,3 +25,4 @@ to more substantial services like those which you might find in production. running_riak_service using_supervisord cfengine_process_management + python_web_app diff --git a/docs/sources/examples/python_web_app.rst b/docs/sources/examples/python_web_app.rst index f31b31b7d2..b44c0e1ee5 100644 --- a/docs/sources/examples/python_web_app.rst +++ b/docs/sources/examples/python_web_app.rst @@ -9,85 +9,86 @@ Python Web App .. include:: example_header.inc -The goal of this example is to show you how you can author your own -Docker images using a parent image, making changes to it, and then -saving the results as a new image. We will do that by making a simple -hello Flask web application image. +While using Dockerfiles is the prefered way to create maintainable +and repeatable images, its useful to know how you can try things out +and then commit your live changes to an image. + +The goal of this example is to show you how you can modify your own +Docker images by making changes to a running +container, and then saving the results as a new image. We will do +that by making a simple 'hello world' Flask web application image. **Steps:** .. code-block:: bash - sudo docker pull shykes/pybuilder + $ sudo docker pull shykes/pybuilder + +Download the ``shykes/pybuilder`` Docker image from the ``http://index.docker.io`` +registry. Note that this container was built with a very old version of docker +(May 2013), but can still be used now. -We are downloading the ``shykes/pybuilder`` Docker image .. code-block:: bash - URL=http://github.com/shykes/helloflask/archive/master.tar.gz + $ sudo docker run -i -t -name pybuilder_run shykes/pybuilder bash -We set a ``URL`` variable that points to a tarball of a simple helloflask web app + $$ URL=http://github.com/shykes/helloflask/archive/master.tar.gz + $$ /usr/local/bin/buildapp $URL + [lots of output later] + $$ exit + + +We then start a new container running interactively using the +image. +First, we set a ``URL`` variable that points to a tarball of a simple +helloflask web app, and then we run a command contained in the image called +``buildapp``, passing it the ``$URL`` variable. The container is +given a name ``pybuilder_run`` which we will use in the next steps. + +While this example is simple, you could run any number of interactive commands, +try things out, and then exit when you're done. .. code-block:: bash - BUILD_JOB=$(sudo docker run -d -t shykes/pybuilder:latest /usr/local/bin/buildapp $URL) - -Inside of the ``shykes/pybuilder`` image there is a command called -``buildapp``, we are running that command and passing the ``$URL`` variable -from step 2 to it, and running the whole thing inside of a new -container. The ``BUILD_JOB`` environment variable will be set with the new container ID. - -.. code-block:: bash - - sudo docker attach -sig-proxy=false $BUILD_JOB - [...] - -While this container is running, we can attach to the new container to -see what is going on. The flag ``--sig-proxy`` set as ``false`` allows you to connect and -disconnect (Ctrl-C) to it without stopping the container. - -.. code-block:: bash - - sudo docker ps -a - -List all Docker containers. If this container has already finished -running, it will still be listed here. - -.. code-block:: bash - - BUILD_IMG=$(sudo docker commit $BUILD_JOB _/builds/github.com/shykes/helloflask/master) + $ sudo docker commit pybuilder_run /builds/github.com/shykes/helloflask/master + c8b2e8228f11b8b3e492cbf9a49923ae66496230056d61e07880dc74c5f495f9 Save the changes we just made in the container to a new image called -``_/builds/github.com/hykes/helloflask/master`` and save the image ID in -the ``BUILD_IMG`` variable name. +``/builds/github.com/hykes/helloflask/master``. You now have 3 different +ways to refer to the container, name, short-id ``c8b2e8228f11``, or +long-id ``c8b2e8228f11b8b3e492cbf9a49923ae66496230056d61e07880dc74c5f495f9``. .. code-block:: bash - WEB_WORKER=$(sudo docker run -d -p 5000 $BUILD_IMG /usr/local/bin/runapp) + $ WEB_WORKER=$(sudo docker run -d -p 5000 /builds/github.com/hykes/helloflask/master /usr/local/bin/runapp) + +Use the new image to create a new container with +network port 5000, and return the container ID and store in the +``WEB_WORKER`` variable (rather than naming a container/image, you can use the ID's). - **"docker run -d "** run a command in a new container. We pass "-d" so it runs as a daemon. - **"-p 5000"** the web app is going to listen on this port, so it must be mapped from the container to the host system. -- **"$BUILD_IMG"** is the image we want to run the command inside of. - **/usr/local/bin/runapp** is the command which starts the web app. -Use the new image we just created and create a new container with -network port 5000, and return the container ID and store in the -``WEB_WORKER`` variable. .. code-block:: bash - sudo docker logs $WEB_WORKER + $ sudo docker logs -f $WEB_WORKER * Running on http://0.0.0.0:5000/ View the logs for the new container using the ``WEB_WORKER`` variable, and if everything worked as planned you should see the line ``Running on http://0.0.0.0:5000/`` in the log output. +To exit the view without stopping the container, hit Ctrl-C, or open another +terminal and continue with the example while watching the result in the logs. + .. code-block:: bash - WEB_PORT=$(sudo docker port $WEB_WORKER 5000 | awk -F: '{ print $2 }') + $ WEB_PORT=$(sudo docker port $WEB_WORKER 5000 | awk -F: '{ print $2 }') Look up the public-facing port which is NAT-ed. Find the private port used by the container and store it inside of the ``WEB_PORT`` variable. @@ -95,23 +96,25 @@ used by the container and store it inside of the ``WEB_PORT`` variable. .. code-block:: bash # install curl if necessary, then ... - curl http://127.0.0.1:$WEB_PORT - Hello world! + $ curl http://127.0.0.1:$WEB_PORT + Hello world! Access the web app using the ``curl`` binary. If everything worked as planned you should see the line ``Hello world!`` inside of your console. -**Video:** +.. code-block:: bash -See the example in action + $ sudo docker ps --all -.. raw:: html +List ``--all`` the Docker containers. If this container had already finished +running, it will still be listed here with a status of 'Exit 0'. - +.. code-block:: bash + + $ sudo docker stop $WEB_WORKER + $ sudo docker rm $WEB_WORKER pybuilder_run + $ sudo docker rmi /builds/github.com/shykes/helloflask/master shykes/pybuilder:latest + +And now stop the running web worker, and delete the containers, so that we can +then delete the images that we used. -Continue to :ref:`running_ssh_service`.