PostgreSQL scaler uses username instead of port number in 2.5.0

[tsndqst]

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The postgreSQL_scaler fails to start up with an error similar to the following:

error establishing postgreSQL connection: dial tcp: address tcp/username: unknown port

#2114 broke the Postgresql scaler. The userName argument overwrites the port argument.

Compare the GetFromAuthOrMeta calls for port and userName. They both set meta.port so it ends up being set to userName not `port.

keda/pkg/scalers/postgresql_scaler.go

Line 90 in 5b71044

meta.port, err = GetFromAuthOrMeta(config, "port")

with

keda/pkg/scalers/postgresql_scaler.go

Line 95 in 5b71044

meta.port, err = GetFromAuthOrMeta(config, "userName")

Expected Behavior

The Postgresql port number is not overwritten by the username value.

Actual Behavior

The username attribute is used in place of the port number. The username value isn't set at all.

Steps to Reproduce the Problem

1. Create a postgresql scaler using a connection configuration similar to the one in the documentation https://keda.sh/docs/2.5/scalers/postgresql/#trigger-specification
2. Watch the operator logs when the scaler stats up. Notice that the scaler attempts to use the username as the port number when connecting to the DB.

Logs from KEDA operator

2022-01-02T20:08:10.467Z        ERROR   scalehandler    error resolving auth params     {"scalerIndex": 0, "object": {"apiVersion": "keda.sh/v1alpha1", "kind": "ScaledObject", "namespace": "default", "name": "pg-scaler"}, "trigger": 0, "error": "error establishing postgreSQL connection: dial tcp: address tcp/username: unknown port"}
github.com/kedacore/keda/v2/controllers/keda.(*ScaledObjectReconciler).getScaledObjectMetricSpecs
        /workspace/controllers/keda/hpa.go:163
github.com/kedacore/keda/v2/controllers/keda.(*ScaledObjectReconciler).newHPAForScaledObject
        /workspace/controllers/keda/hpa.go:63
github.com/kedacore/keda/v2/controllers/keda.(*ScaledObjectReconciler).updateHPAIfNeeded
        /workspace/controllers/keda/hpa.go:124
github.com/kedacore/keda/v2/controllers/keda.(*ScaledObjectReconciler).ensureHPAForScaledObjectExists
        /workspace/controllers/keda/scaledobject_controller.go:376
github.com/kedacore/keda/v2/controllers/keda.(*ScaledObjectReconciler).reconcileScaledObject
        /workspace/controllers/keda/scaledobject_controller.go:228
github.com/kedacore/keda/v2/controllers/keda.(*ScaledObjectReconciler).Reconcile
        /workspace/controllers/keda/scaledobject_controller.go:179
sigs.k8s.io/controller-runtime/pkg/internal/controller.(*Controller).Reconcile
        /go/pkg/mod/sigs.k8s.io/controller-runtime@v0.10.3/pkg/internal/controller/controller.go:114
sigs.k8s.io/controller-runtime/pkg/internal/controller.(*Controller).reconcileHandler
        /go/pkg/mod/sigs.k8s.io/controller-runtime@v0.10.3/pkg/internal/controller/controller.go:311
sigs.k8s.io/controller-runtime/pkg/internal/controller.(*Controller).processNextWorkItem
        /go/pkg/mod/sigs.k8s.io/controller-runtime@v0.10.3/pkg/internal/controller/controller.go:266
sigs.k8s.io/controller-runtime/pkg/internal/controller.(*Controller).Start.func2.2
        /go/pkg/mod/sigs.k8s.io/controller-runtime@v0.10.3/pkg/internal/controller/controller.go:227

KEDA Version

2.5.0

Kubernetes Version

1.21

Platform

Other

Scaler Details

PostgreSQL

Anything else?

2.4.0 works as expected.

[zroubalik]

@tsndqst good catch, thx. Are you wiling to open a PR with the fix?

[tsndqst]

@zroubalik I created a PR but I don't know Go data structures well enough to come up with a test.

[zroubalik]

@tsndqst I think that it is fine, no need to add a test for this.