Update counter demo with external volume using mock volume plugin.

It makes the file counter path configurable so we can test it
against different volume types. And adds an optional file verification step to
test the presence of a file on an existing volume.

Author: msau42

demos/counter/counter.go

@@ -27,6 +27,7 @@ import (
 	"net"
 	"net/http"
 	"os"
+	"path/filepath"
 	"strconv"
 	"sync"
 	"sync/atomic"
@@ -41,27 +42,27 @@ var (
 	fileMutex    sync.Mutex
 )
 
-const fileCounterPath = "/home/counter/a.txt"
-
-func incrementFileCounter() int {
+func incrementFileCounter(filePath string) int {
 	fileMutex.Lock()
 	defer fileMutex.Unlock()
 	counter := 0
-	data, err := os.ReadFile(fileCounterPath)
+	data, err := os.ReadFile(filePath)
 	if err == nil {
 		if i, err := strconv.Atoi(string(data)); err == nil {
 			counter = i
 		}
 	}
 	counter++
-	err = os.WriteFile(fileCounterPath, []byte(strconv.Itoa(counter)), 0o644)
+	err = os.WriteFile(filePath, []byte(strconv.Itoa(counter)), 0o644)
 	if err != nil {
 		return -1
 	}
 	return counter
 }
 
 func main() {
+	fileCounterDirectory := pflag.String("file-counter-directory", "/home/counter", "Directory for file counter")
+	validateExistingFilePath := pflag.String("validate-existing-file-path", "", "Path to existing file to validate reading")
 	pflag.Parse()
 	ctx := context.Background()
 
@@ -70,11 +71,23 @@ func main() {
 	defaultMux := http.NewServeMux()
 	defaultMux.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
 		ctx := r.Context()
-		fileCounter := incrementFileCounter()
-
+		fileCounter := incrementFileCounter(filepath.Join(*fileCounterDirectory, "a.txt"))
 		memoryCounter := atomic.AddUint64(&requestCount, 1)
 		currentIP := getCurrentIP()
-		response := fmt.Sprintf("hello from: %s | preserved memory count: %d | preserved file counter: %d\n", currentIP, memoryCounter, fileCounter)
+
+		fileContentStr := ""
+		if *validateExistingFilePath != "" {
+			fileContent, err := os.ReadFile(*validateExistingFilePath)
+			if err != nil {
+				fileResponse := fmt.Sprintf("failed to read test file: %s\n", err.Error())
+				w.WriteHeader(http.StatusOK)
+				w.Write([]byte(fileResponse))
+				return
+			}
+			fileContentStr = fmt.Sprintf(" | file content: %s", string(fileContent))
+		}
+
+		response := fmt.Sprintf("hello from: %s | preserved memory count: %d | preserved file counter: %d%s\n", currentIP, memoryCounter, fileCounter, fileContentStr)
 		slog.InfoContext(ctx, "Handled request", slog.String("response", response))
 
 		w.WriteHeader(http.StatusOK)

demos/counter/counter.yaml.tmpl

@@ -42,14 +42,16 @@ spec:
   containers:
   - name: counter
     image: ko://github.com/agent-substrate/substrate/demos/counter
-    command: ["/ko-app/counter"]
+    command: ["/ko-app/counter", "--validate-existing-file-path=/external-data/test.txt"]
     readyz:
       httpGet:
         path: /readyz
         port: 80
     volumeMounts:
     - name: data
       mountPath: /home/counter
+    - name: external-data
+      mountPath: /external-data
   workerSelector:
     matchLabels:
       workload: counter
@@ -60,3 +62,7 @@ spec:
   volumes:
   - name: data
     durableDir: {}
+  - name: external-data
+    externalVolumeTemplate:
+      capacity: 1Gi
+      storageClassName: standard

hack/run-demo-counter-kind.sh

@@ -0,0 +1,74 @@
+#!/usr/bin/env bash
+
+# Copyright 2026 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+set -o errexit -o nounset -o pipefail
+
+ROOT="$(cd "$(dirname "$0")/.." && pwd)"
+cd "${ROOT}"
+
+# ANSI color codes for pretty output
+COLOR_CYAN='\033[1;36m'
+COLOR_GREEN='\033[1;32m'
+COLOR_YELLOW='\033[1;33m'
+COLOR_RED='\033[1;31m'
+COLOR_RESET='\033[0m'
+
+function log_step() {
+  echo -e "${COLOR_CYAN}[step]: $1${COLOR_RESET}"
+}
+
+function log_success() {
+  echo -e "${COLOR_GREEN}[success]: $1${COLOR_RESET}"
+}
+
+function log_warn() {
+  echo -e "${COLOR_YELLOW}[warning]: $1${COLOR_RESET}"
+}
+
+function log_error() {
+  echo -e "${COLOR_RED}[error]: $1${COLOR_RESET}"
+}
+
+log_step "Cleaning up previous test"
+./hack/delete-kind-cluster.sh || true
+
+log_step "Installing kind cluster"
+./hack/create-kind-cluster.sh
+
+log_step "Installing ATE control plane, Valkey, and RustFS..."
+./hack/install-ate-kind.sh --deploy-ate-system
+
+log_step "Installing counter demo..."
+./hack/install-ate-kind.sh --deploy-demo-counter
+
+log_step "Installing kubectl-ate CLI..."
+go install ./cmd/kubectl-ate
+
+log_step "Creating atespace (demo)..."
+kubectl ate create atespace demo
+
+log_step "Creating counter actor (my-counter-1)..."
+kubectl ate create actor my-counter-1 --template ate-demo-counter/counter --atespace demo
+
+log_success "Counter actor my-counter-1 created"
+echo ""
+echo -e "${COLOR_YELLOW}========================================================================${COLOR_RESET}"
+echo -e "To interact with the counter actor, open a separate terminal and run:"
+echo -e "  curl -X POST -H \"Host: my-counter-1.demo.actors.resources.substrate.ate.dev\" -i http://localhost:8000/"
+echo -e "${COLOR_YELLOW}========================================================================${COLOR_RESET}"
+echo ""
+log_step "Starting port-forwarding for the network router (press Ctrl+C to stop)..."
+kubectl port-forward -n ate-system svc/atenet-router 8000:80