How can I obtain spec.replicas metadata and reference it elsewhere in configuration?

I am configuring a StatefulSet where I want the number of replicas (spec.replicas as shown below) available to somehow pass as a parameter into the application instance. My application needs spec.replicas to determine the number of replicas so it knows what rows to load from a MySQL table. I don't want to hard-code the number of replicas in both spec.replicas and the application parameter as that will not work when scaling the number of replicas up or down, since the application parameter needs to adjust when scaling.

Here is my StatefulSet config:

apiVersion: apps/v1beta1kind: StatefulSetmetadata:  labels:    run: my-app  name: my-app  namespace: my-nsspec:  replicas: 3  selector:    matchLabels:      run: my-app  serviceName: my-app  podManagementPolicy: Parallel  template:    metadata:      labels:        run: my-app    spec:      containers:      - name: my-app        image: my-app:latest        command:          - /bin/sh          - /bin/start.sh          - dev          - 2000m          - "0"          - "3" # **Needs to be replaced with # of replicas**          - 127.0.0.1          - "32990"        imagePullPolicy: Always        livenessProbe:          httpGet:            path: /health            port: 8081          initialDelaySeconds: 180          periodSeconds: 10          timeoutSeconds: 3        readinessProbe:          failureThreshold: 10          httpGet:            path: /ready            port: 8081            scheme: HTTP          initialDelaySeconds: 30          periodSeconds: 15          successThreshold: 1          timeoutSeconds: 3        ports:        - containerPort: 8080          protocol: TCP        resources:          limits:            memory: 2500Mi      imagePullSecrets:      - name: snapshot-pull      restartPolicy: Always

I have read the Kubernetes docs and the spec.replicas field is scoped at the pod or container level, never the StatefulSet, at least as far as I have seen.