Cant build worker image for the voting app demo || worker - Dockerfile

Docker
#1

As I was building the images for the voting application, I found the below issue

Building image for: worker
Dockerfile: https://github.com/dockersamples/example-voting-app/tree/main/worker

Command used: ~/Documents/kk_voting_app/example-voting-app/worker$ sudo docker build -t worker .

Error output:

DEPRECATED: The legacy builder is deprecated and will be removed in a future release.
            Install the buildx component to build images with BuildKit:
            https://docs.docker.com/go/buildx/
Sending build context to Docker daemon  9.728kB
Step 1/14 : FROM --platform=${BUILDPLATFORM} mcr.microsoft.com/dotnet/sdk:7.0 as build
failed to parse platform : "" is an invalid component of "": platform specifier component must match "^[A-Za-z0-9_-]+$": invalid argument
#2

An example of how to build the dockerfile is given in the comments in the dockerfile.
You haven’t specified a target platform for the build.

For Intel processor machines (everything except M-Series Macs), the command would be

docker buildx build --platform linux/amd64 .
#3

Tried the above, the buildx command is not recognized

#4
#5

hey, the buildx seems to work now. But, even though I have successfully run the worker container, it is not functioning as excepted

After I cast the vote. In the results web page, I’m only shown with the result of 50:50, no matter if I change my vote, its not changing the result. I doubt this issue may be linked to the worker container. But I’m not sure why

#6

I can’t comment on the functionality of the system itself without digging into all the code.
The exercise is to prove that you can stand up a multi container application and all the components talk to each other - which you have done.

As a DevOps engineer, your work is complete here. Incorrect operation of the application itself is something that DevOps would send back to the development team,

#7

Understandable! thanks for the troubleshooting.

Another observation is that, the same application I ran it using docker-compose technique and it worked fine.

#8

Try this, I was facing the same issue in the excercise. But finally got it working:

First install buildx:

sudo apt install docker-buildx

Then build with the command given in the Dockerfile for the worker:

docker buildx build --platform "linux/arm64/v8" . -t worker-app

And then the image is ready:

root@ubuntu:/home/asulikeri/codebase/udemy/example-voting-app/worker# docker images
REPOSITORY        TAG         IMAGE ID       CREATED             SIZE
worker-app        latest      e219b0a20939   49 seconds ago      196MB```