Newline character added to Prometheus Custom Auth

[Amir-Wollman]

Report

It seems whenever using a secretRef with Prometheus CustomAuth auth type, a new line is either added or not removed from the actual values.

Expected Behavior

Using the below manifests, Keda should be able to retrieve metrics from Prometheus:

apiVersion: v1
items:
- apiVersion: keda.sh/v1alpha1
  kind: ClusterTriggerAuthentication
  metadata:
    finalizers:
    - finalizer.keda.sh
    name: keda-prom-creds
  spec:
    secretTargetRef:
    - key: PRIVATE_KEY
      name: secret-keys
      parameter: customAuthValue
    - key: authToken
      name: secret-keys
      parameter: customAuthHeader
kind: List

where value is:

  authToken: dG9rZW4K (== "token")

Actual Behavior

Keda operator fails with error: net/http: invalid header field name \"token\\n\"

2023-09-07T06:33:13Z	ERROR	scale_handler	error getting metric for scaler	{"scaledObject.Namespace": "hpa-tenant", "scaledObject.Name": "prometheus-so-test-metric", "scaler": "prometheusScaler", "error": "Get \"https://prom-server.com/api/v1/query?query=sum%28rate%28container_cpu_usage_seconds_total%7Bnamespace%3D~%22.%2Ahpa-tenant.%2A%22%2Ccontainer%3D%22dal%22%7D%5B5m%5D%29+%2F+%28kube_pod_container_resource_limits%7Bnamespace%3D~%22.%2Ahpa-tenant.%2A%22%2Ccontainer%3D%22dal%22%2Cresource%3D%22cpu%22%7D%29%29+by+%28container%2C+namespace%29+%2A+100&time=2023-09-07T06:33:13Z\": net/http: invalid header field name \"token\\n\""}

Steps to Reproduce the Problem

1. Create a secret (in this example was created with ExternalSecrets)
2. Reference the secret in TriggerAuthentication

Logs from KEDA operator

2023-09-07T06:33:13Z	ERROR	scale_handler	error getting metric for scaler	{"scaledObject.Namespace": "hpa-tenant", "scaledObject.Name": "prometheus-so-test-metric", "scaler": "prometheusScaler", "error": "Get \"https://prom-server.com/api/v1/query?query=sum%28rate%28container_cpu_usage_seconds_total%7Bnamespace%3D~%22.%2Ahpa-tenant.%2A%22%2Ccontainer%3D%22dal%22%7D%5B5m%5D%29+%2F+%28kube_pod_container_resource_limits%7Bnamespace%3D~%22.%2Ahpa-tenant.%2A%22%2Ccontainer%3D%22dal%22%2Cresource%3D%22cpu%22%7D%29%29+by+%28container%2C+namespace%29+%2A+100&time=2023-09-07T06:33:13Z\": net/http: invalid header field name \"token\\n\""}

KEDA Version

2.11.1

Kubernetes Version

1.27

Platform

Amazon Web Services

Scaler Details

Prometheus

Anything else?

No response

[Amir-Wollman]

Fixed in PR #4959