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https://github.com/jedevc/docker-dino-demo

🦕 Deploying a dinosaur web app using docker!
https://github.com/jedevc/docker-dino-demo

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🦕 Deploying a dinosaur web app using docker!

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README 

        
# Docker demo



**This is the demo from my slides [here](https://docs.google.com/presentation/d/1K7yt9h-T9BoDUA_im8-Tqd-ok1N-tJGDwSGo6hTQkO0/edit?usp=sharing).**



Let's deploy a flask web app in Docker!



## Startup



First let's build our image!



    $ docker build . -t docker-dino



Now we can run it:



    $ docker run -d docker-dino

    69a3f27004e6c62c5227d594e87aa969b48eedf45448d6f62aaa7182f409371b

    $ docker ps

    CONTAINER ID        IMAGE              COMMAND                  CREATED             STATUS              PORTS               NAMES

    69a3f27004e6        docker-dino        "/bin/sh -c 'gunicor…"   14 seconds ago      Up 11 seconds       80/tcp              sharp_darwin



And we can now see our container is now running. But how can we actually

access it?



To do that, we can restart our container, but this time expose port 80 from

the container to port 8080 on our host!



    $ docker kill 69a3f27004e6

    69a3f27004e6

    $ docker run -p 8000:80 -d docker-dino 

    74470db53fe64cc0b457afb1ba6552145f267c698ddaa28624a62832812d1a16

    $ docker ps

    CONTAINER ID        IMAGE              COMMAND                  CREATED             STATUS                  PORTS                  NAMES

    74470db53fe6        docker-dino        "/bin/sh -c 'gunicor…"   2 seconds ago       Up Less than a second   0.0.0.0:8000->80/tcp   recursing_khorana



Now that the port is published, we can access our site:



    $ curl localhost:8000

    Hello World (and dinosaurs)!



## File uploads



Let's try and send a file to our website.



    $ curl http://localhost:8000/upload -F "[email protected]"

    

    500 Internal Server Error

    
Internal Server Error


    
The server encountered an internal error and was unable to complete your request. Either the server is overloaded or there is an error in the application.



Uh oh! We got an internal server error!



Docker lets us peek inside the container to have a look what's going on.



    $ docker logs 74470db53fe6

    [2019-11-21 16:27:54 +0000] [6] [INFO] Starting gunicorn 20.0.0

    [2019-11-21 16:27:54 +0000] [6] [INFO] Listening at: http://0.0.0.0:80 (6)

    [2019-11-21 16:27:54 +0000] [6] [INFO] Using worker: sync

    [2019-11-21 16:27:54 +0000] [10] [INFO] Booting worker with pid: 10

    [2019-11-21 16:28:08,911] ERROR in app: Exception on /upload [POST]

    Traceback (most recent call last):

    ...

    File "/app/dino/dino.py", line 27, in upload

        file.save(os.path.join(UPLOADS, out_filename))

    ...

    FileNotFoundError: [Errno 2] No such file or directory: '/app/uploads/dino.txt'



Aha! The directory we're trying to upload files to doesn't exist!



We'll fix this later in the Dockerfile, but for now, we'll use another

technique to patch the container while it's running!



    $ docker exec -it 74470db53fe6 /bin/bash

    root@74470db53fe6:/app# ls

    Pipfile  Pipfile.lock  README.md  demo

    root@74470db53fe6:/app# mkdir uploads



Now we want to exit the container with ctrl-d and we can try the upload again:



    $ curl http://localhost:8000/upload -F "[email protected]"

    

    Redirecting...

    
Redirecting...


    
You should be redirected automatically to target URL: /files/dino.txt.  If not click the link.



Great! We should then be able to easily get the dinosaur:



    $ curl http://localhost:8000/dinos/dino.txt

           __

          /oo\

         |    |

     ^^  (vvvv)   ^^

     \\  /\__/\  //

      \\/      \//

       /        \        

      |          |    ^  

      /          \___/ | 

     (            )     |

      \----------/     /

        //    \\_____/

       W       W 



We can then patch our Dockerfile for future containers:



```Dockerfile

...

ENV UPLOADS_DIR=uploads/

RUN mkdir -p uploads/

...

```