Frontend Unable to Connect to Backend in Kubernetes and Docker Deployments: Requests Default to Localhost

[nick1ee]

We attempted to deploy Dataline to our Kubernetes environment, but it’s not working as expected. It appears that I can access the frontend through the custom domain, but the connections from the frontend are being blocked.

The frontend is trying to send requests to http://localhost:7377 for health checks and other operations.

We also tried running Dataline on a VM using docker run and accessed the web interface via the VM’s IP address. The result was the same: we could reach the frontend, but the frontend couldn’t connect to the backend, as it was still trying to send requests to localhost.

Additionally, we tried setting the ALLOW_ORIGINS environment variable to include our custom domain, but it doesn’t seem to have any effect.

How can I change the default domain for the backend? It should match the custom domain I use to access the frontend, rather than defaulting to localhost.

[RamiAwar]

There's a frontend variable for the backend host as well!

Set "VITE_API_URL" to point to your backend.

We might not have documented I'll double check.

Allowed origins is only important to set if you're using authentication.

Let me know if that works!

[Pin-Jui]

I’m Nick’s colleague.
We tried the following two configurations, but we are still facing the same issue:

docker run -p 7377:7377 -v dataline:/home/.dataline --name dataline-external -e API_URL="http://EXTERNAL_IP:7377/" ramiawar/dataline:latest

docker run -p 7377:7377 -v dataline:/home/.dataline --name dataline-external -e API_URL="http://0.0.0.0:7377/" ramiawar/dataline:latest

[RamiAwar]

I see.. Can you share more about your kubernetes config? I think the problem lies there.

[RamiAwar]

In the first line you sent, is EXTERNAL_IP a bash variable?

[Pin-Jui]

We run these commands on GCP VM instead of GKE to test ENV, but still the same
docker run -p 7377:7377 -v dataline:/home/.dataline --name dataline-external ramiawar/dataline:latest

This is our GKE statefulset config:

apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: dataline
  namespace: dataline
  labels:
    app: dataline
spec:
  serviceName: "dataline"
  replicas: 1
  selector:
    matchLabels:
      app: dataline
  template:
    metadata:
      labels:
        app: dataline
    spec:
      containers:
        - image: ramiawar/dataline:latest
          name: dataline
          imagePullPolicy: IfNotPresent
          ports:
            - containerPort: 7377
              name: backend
          resources:
            requests:
              cpu: 1000m
              memory: 2000Mi
            limits:
              cpu: 1000m
              memory: 2000Mi
          livenessProbe:
            httpGet:
              path: /
              port: 7377
            initialDelaySeconds: 10
            periodSeconds: 20
            timeoutSeconds: 10
          readinessProbe:
            httpGet:
              path: /
              port: 7377
            initialDelaySeconds: 10
            periodSeconds: 20
            timeoutSeconds: 10
          volumeMounts:
            - name: data
              mountPath: /home/.dataline
  volumeClaimTemplates:
    - metadata:
        name: data
      spec:
        accessModes: [ "ReadWriteOnce" ]
        resources:
          requests:
            storage: 10Gi

[Pin-Jui]

EXTERNAL_IP is our GCE VM external IP

[anthony2261]

Hey @nick1ee, thanks for raising the issue. I've looked into it and am working on a fix. The problem is that the docker image serves the frontend app via the backend, and it serves the bundle that was packaged during the docker image build, so it has no way of seeing what the environment variable is at any time.

For the time being, I suggest you do this until the proper fix is released:

• build the docker image yourself while specifying your api url: docker build --build-arg API_URL="http://localhost:7376" -t dataline . . Of course you should replace http://localhost:7376 with your own value.
• use the image you just built. Since you're using Kubernetes I'll assume you know how to run the locally built image (you can even push your image to docker hub for example and point to that instead of ramiawar/dataline)

I've tried it out myself and can confirm that I was able to open the app using a custom url. The proper fix will be done soon but I can't guarantee when the next release will happen. Hope this helps!

Edit: Don't forget to set the ALLOWED_ORIGINS variable too!

[RamiAwar]

Support for this is now in the latest release FYI! Try it out and let us know if any problem remains 🙂

Thanks for bringing this up and helping us improve!