Learn to use Docker in Development - Part 1

Learn how to use docker images & containers to create a multi-part Ruby on Rails development environment.

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Please watch: "How to Write Better Automated Tests"
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[jeffmjack]

If you're following along in 2019 or later, and you get an error when running `gem install rails`, you need to be starting docker with a later version of Ruby than what he's doing here, with a command like `docker run --rm -it -v "$PWD:/app" ruby:2.5 bash`, or whatever version the rails website says is the current minimum latest version for ruby.

[lizcooper]

Thanks - exactly what I was looking for. This is the best example of networking an app and db in Docker I ‘ve seen.

[gabrielecalvo]

In case you are running Docker on Windows and you get a weird "C:\Program Files\Docker Toolbox\docker.exe: invalid reference format: repository name must be lowercase." make sure "$PWD:/usr/src/app" is surrounded by quotes (unlike in the video at 13:30).

[CPEDGG]

Shared, Liked, Subscribed. Thanks for the video, please keep making them, they are clear and concise.

[dannunziostefano]

Great
Any chance on a tutorial on how to forward ssh key to a container, so docker can pull from private repos?

[donjciii]

Keith, thank you very much for this tutorial, very well explained and put together! Shared, liked and subscribed a long time ago :-)

[TroyMurray]

Another great job on showing to use Docker. I did run into an issue and wanted to share. Where you had us create the welcome_controller.rb file and render the text, this didn't work on Rails 5.1.3, as it was looking for a view file for the show action and puma would throw an error. I created the file and then the page displayed correctly.

[Sonekkah]

Very well explained. I watched alongside learndocker.online and it was easy to understand.

[ToddEmpcke]

Thanks for the tutorial however clearly I missed something. you did not use sudo while executing docker run, then in bash you were root when you executed rails, which if you use ls -al (for me at least) makes all of the generated files owned by root. So in atom when I try to modify one of those files I can't because they are owned by root. You did not seem to have an issue, and no one else has commented so please let me know where I went wrong?

[LiaAdzumi]

Hi,

After following closely your tutorial (I spent 2 days on this single video), which is very hard to follow on Windows, I could manage up to here "C:\Users\ing\app\blog>docker build -t blog ."

But, I could not continue it because I got this message "'export' is not recognized as an internal or external command,
operable program or batch file.", after executing this command "export POSTGRES_USER="ing" "

You are doing good, but not for a beginners who are using Windows like myself. You jumped from one terminal to another terminal, moved from a directory to different directory without clear explanation.

There are a lot smart people like you published video tutorials, but they might not think about who the absolute beginners.

But I still thanks for your efforts to teach us.
So, please do make a very clear explanation in every step of your movement.

So, can you or any body help me to solve the above problem?

Thanks.

[AravindKumar-viul]

Hi CoderJourney,

Your videos about dockers are superb. I don't understand the usage and context of the following command which you've ran,

docker run --rm .... -net=blog blog rake db:setup

[VolodymyrKuchinskyi-zu]

Nice work, very informational content ))

[scrambledoracle]

CoderJourney thanks for this video. One problem that I keep encountering is that my shared volume is owned by root which prevents other resources from accessing the files. Any advice you can throw my way?

[sameeraappana]

What if I don't want to use POSTGRES but continue with sqlite3. How to write a Dockerfile then??

[carloslora]

Error response from daemon: create $PWD: "$PWD" includes invalid characters for a local volume name | 2:40

[cosmic]

I seem to be getting this error... Tried to find answers on google but none worked.
C:/Program Files/Docker Toolbox/docker.exe: Error response from daemon: invalid
mode:
See 'C:/Program Files/Docker Toolbox/docker.exe run --help'.

[kelvinromero]

Hi CoderJourney,

I'm having a little trouble here. The container worked at first, but I got no response in the browser. I tried to analyse the network but wasn't sure what to look for. I tried to remove the container then run it again, but I'm getting a error (That rails is server is already running).

I'm using boot2docker. And I'm not sure what the network should looks like on Virtualbox, Docker-machine and Windows (I used netstat to check for the port 3000, and wasn't there)

[patrickkuhn]

As from rails 4.1 rails deprecated 'render text:'. Use 'render html:' instead.

[bradchellingworth]

Perhaps i missed a step here, but it seems you pass a db user and password and use it to create the database, but at no point to we set that user up in postgres? I just errors at that point saying role doesn't exist and I cant get my head around how you can create a db without having set up a user first?

When creating the db we should do something like CREATE ROLE new_user WITH CREATEDB CREATEROLE SUPERUSER;

[NamNguyen-sgrq]

Hi,
I follow your tutorial on window, everything works fine, except that when I refresh localhost:3000, it doesn't work (This site can’t be reached). Do you have any suggestion?. And where does /usr/src/app come from, I have a error relating to this in part 2(invalid bind mount spec invalid volume specification:
Thank you.