How to change default key names in a struct and delete the rest of items in GO

Question

I need to change the name of the keys in a struct through go.

I have this function

func (p *DbConfig) myfunction(prefix string, namespace string, dbName string, userSecret string) []corev1.EnvVar {
       prefix = Underscore(prefix)
       namespace = Underscore(namespace)
        

        envs := filter(p.myfunction(prefix), func(item corev1.EnvVar) bool {
        if item.Name == "USER" {
            return false
        }
        if item.Name == "PASSWORD" {
            return false
        }
        return true
     })


    return append(envs, []corev1.EnvVar{
        {
            Name:  prefix + "DB_NAME",
            Value: namespace + dbName,
        },
        {
            Name: prefix + "DB_USER",
            ValueFrom: &corev1.EnvVarSource{
                SecretKeyRef: &corev1.SecretKeySelector{
                    LocalObjectReference: corev1.LocalObjectReference{
                        Name: userSecret,
                    },
                    Key: "POSTGRES_USER",
                },
            },
        },
        {
            Name: prefix + "DB_PASSWORD",
            ValueFrom: &corev1.EnvVarSource{
                SecretKeyRef: &corev1.SecretKeySelector{
                    LocalObjectReference: corev1.LocalObjectReference{
                        Name: userSecret,
                    },
                    Key: "POSTGRES_PASSWORD",
                },
            },
        },
    }...)
}

Where EnVar struct looks like

type EnvVar struct {
    Name string `json:"name" protobuf:"bytes,1,opt,name=name"`

    Value string `json:"value,omitempty" protobuf:"bytes,2,opt,name=value"`

    ValueFrom *EnvVarSource `json:"valueFrom,omitempty" protobuf:"bytes,3,opt,name=valueFrom"`
}

type EnvVarSource struct {


    FieldRef *ObjectFieldSelector `json:"fieldRef,omitempty" protobuf:"bytes,1,opt,name=fieldRef"`

    ResourceFieldRef *ResourceFieldSelector `json:"resourceFieldRef,omitempty" protobuf:"bytes,2,opt,name=resourceFieldRef"`

    ConfigMapKeyRef *ConfigMapKeySelector `json:"configMapKeyRef,omitempty" protobuf:"bytes,3,opt,name=configMapKeyRef"`

    SecretKeyRef *SecretKeySelector `json:"secretKeyRef,omitempty" protobuf:"bytes,4,opt,name=secretKeyRef"`
}

and here I need to change the values containing "CONTAINER" with the correct env vars used in the container.

func containerEnvs(hub *immv1alpha1.ImmHub, instance *immv1alpha1.Container) []corev1.EnvVar {
    postgresService := hub.Spec.DbConfig.myfunction("CONTAINER_", hub.Namespace, instance.Spec.dbName, instance.Spec.userSecret)
    
    //Here I want to modify the keys of the struct that I need so that correct environment variables are passed

    postgresService[0].Name = "DATABASE_NAME"
    postgresService[1].Name = "DATABASE_USER"

    service := []corev1.EnvVar{
        {
            Name:  "DATABASE_NAME",
            Value: instance.Spec.dbName,
        }
    }
    return append(service, append(postgresService)...)

}

The output of the postgresService variable looks like

[{CONTAINER_DB_NAME testdb nil} {CONTAINER_DB_USER  &EnvVarSource{FieldRef:nil,ResourceFieldRef:nil,ConfigMapKeyRef:nil,SecretKeyRef:&SecretKeySelector{LocalObjectReference:LocalObjectReference{Name:secret,},Key:POSTGRES_USER,Optional:nil,},}} {CONTAINER_DB_PASSWORD  &EnvVarSource{FieldRef:nil,ResourceFieldRef:nil,ConfigMapKeyRef:nil,SecretKeyRef:&SecretKeySelector{LocalObjectReference:LocalObjectReference{Name:secret,},Key:POSTGRES_PASSWORD,Optional:nil,},}}]

I have two problems here:

1- Is this the best way to change the default key names in my case?

2- If the variable postgresService contains more values but I just need the DATABASE_NAME and DATABASE_USER how can I delete the rest of the values from postgresService?