Add feature flag to enable shared cache

java/operator/org.eclipse.theia.cloud.operator/src/main/java/org/eclipse/theia/cloud/operator/TheiaCloudOperatorArguments.java

@@ -122,6 +122,14 @@ public enum BandwidthLimiter {
             "--oAuth2ProxyVersion" }, description = "The version to use of the quay.io/oauth2-proxy/oauth2-proxy image.", required = false, defaultValue = "latest")
     private String oAuth2ProxyVersion;
 
+    @Option(names = {
+            "--enableCaching" }, description = "Whether to enable caching of Theia application containers.", required = false)
+    private boolean enableCaching = true;
+
+    @Option(names = {
+            "--cacheUrl" }, description = "The URL of the remote cache server.", required = false, defaultValue = "http://theia-cloud-combined-cache:8080/cache/")
+    private String cacheUrl;
+
     public boolean isUseKeycloak() {
         return useKeycloak;
     }
@@ -222,6 +230,14 @@ public String getOAuth2ProxyVersion() {
         return oAuth2ProxyVersion;
     }
 
+    public boolean isEnableCaching() {
+        return enableCaching;
+    }
+
+    public String getCacheUrl() {
+        return cacheUrl;
+    }
+
     @Override
     public int hashCode() {
         final int prime = 31;
@@ -251,6 +267,8 @@ public int hashCode() {
         result = prime * result + (usePaths ? 1231 : 1237);
         result = prime * result + ((wondershaperImage == null) ? 0 : wondershaperImage.hashCode());
         result = prime * result + ((oAuth2ProxyVersion == null) ? 0 : oAuth2ProxyVersion.hashCode());
+        result = prime * result + (enableCaching ? 1231 : 1237);
+        result = prime * result + ((cacheUrl == null) ? 0 : cacheUrl.hashCode());
         return result;
     }
 
@@ -352,6 +370,13 @@ public boolean equals(Object obj) {
                 return false;
         } else if (!oAuth2ProxyVersion.equals(other.oAuth2ProxyVersion))
             return false;
+        if (enableCaching != other.enableCaching)
+            return false;
+        if (cacheUrl == null) {
+            if (other.cacheUrl != null)
+                return false;
+        } else if (!cacheUrl.equals(other.cacheUrl))
+            return false;
         return true;
     }
 
@@ -367,7 +392,8 @@ public String toString() {
                 + ", keycloakClientId=" + keycloakClientId + ", leaderLeaseDuration=" + leaderLeaseDuration
                 + ", leaderRenewDeadline=" + leaderRenewDeadline + ", leaderRetryPeriod=" + leaderRetryPeriod
                 + ", maxWatchIdleTime=" + maxWatchIdleTime + ", continueOnException=" + continueOnException
-                + ", oAuth2ProxyVersion=" + oAuth2ProxyVersion + "]";
+                + ", oAuth2ProxyVersion=" + oAuth2ProxyVersion + ", enableCaching=" + enableCaching + ", cacheUrl="
+                + cacheUrl + "]";
     }
 
 }

java/operator/org.eclipse.theia.cloud.operator/src/main/java/org/eclipse/theia/cloud/operator/handler/AddedHandlerUtil.java

@@ -54,6 +54,11 @@
 
 import io.fabric8.kubernetes.api.model.ConfigMap;
 import io.fabric8.kubernetes.api.model.ConfigMapEnvSource;
+import io.fabric8.kubernetes.api.model.ConfigMapVolumeSource;
+import io.fabric8.kubernetes.api.model.ObjectMeta;
+import io.fabric8.kubernetes.api.model.OwnerReference;
+import io.fabric8.kubernetes.api.model.Volume;
+import io.fabric8.kubernetes.api.model.VolumeMount;
 import io.fabric8.kubernetes.api.model.Container;
 import io.fabric8.kubernetes.api.model.EnvFromSource;
 import io.fabric8.kubernetes.api.model.EnvVar;
@@ -63,6 +68,9 @@
 import io.fabric8.kubernetes.api.model.SecretEnvSource;
 import io.fabric8.kubernetes.api.model.apps.Deployment;
 import io.fabric8.kubernetes.client.NamespacedKubernetesClient;
+import org.eclipse.theia.cloud.common.util.NamingUtil;
+import org.eclipse.theia.cloud.operator.TheiaCloudOperatorArguments;
+import org.eclipse.theia.cloud.operator.util.TheiaCloudHandlerUtil;
 
 public final class AddedHandlerUtil {
 
@@ -249,6 +257,65 @@ public static void addImagePullSecret(Deployment deployment, String secret) {
         imagePullSecrets.add(new LocalObjectReference(secret));
     }
 
+    /**
+     * Configure Gradle remote build cache by setting environment variables.
+     * The Gradle init script baked into the image will pick these up automatically.
+     *
+     * Environment variables set:
+     * - GRADLE_REMOTE_CACHE_ENABLED: "true" or "false" (explicit toggle)
+     * - GRADLE_REMOTE_CACHE_URL: The cache server URL (only if enabled)
+     * - GRADLE_REMOTE_CACHE_PUSH: "true" or "false" (only if enabled)
+     */
+    public static void configureGradleCaching(String correlationId, Deployment deployment,
+                                              AppDefinition appDefinition,
+                                              TheiaCloudOperatorArguments arguments) {
+        // Find the theia container
+        Optional<Integer> maybeIdx = findContainerIdxInDeployment(deployment, appDefinition.getSpec().getName());
+        if (maybeIdx.isEmpty()) {
+            LOGGER.warn(formatLogMessage(correlationId, "Could not find theia container to configure Gradle caching"));
+            return;
+        }
+
+        int idx = maybeIdx.get();
+        Container container = deployment.getSpec().getTemplate().getSpec().getContainers().get(idx);
+
+        // Initialize env list if null
+        if (container.getEnv() == null) {
+            container.setEnv(new ArrayList<>());
+        }
+
+        // Determine if caching should be enabled
+        boolean cachingEnabled = arguments != null
+                && arguments.isEnableCaching()
+                && arguments.getCacheUrl() != null
+                && !arguments.getCacheUrl().trim().isEmpty();
+
+        // Always set the ENABLED variable for explicit control
+        EnvVar cacheEnabledEnv = new EnvVar();
+        cacheEnabledEnv.setName("GRADLE_REMOTE_CACHE_ENABLED");
+        cacheEnabledEnv.setValue(String.valueOf(cachingEnabled));
+        container.getEnv().add(cacheEnabledEnv);
+
+        if (cachingEnabled) {
+            // Set cache URL
+            EnvVar cacheUrlEnv = new EnvVar();
+            cacheUrlEnv.setName("GRADLE_REMOTE_CACHE_URL");
+            cacheUrlEnv.setValue(arguments.getCacheUrl().trim());
+            container.getEnv().add(cacheUrlEnv);
+
+            // Set push permission (default: true, could be made configurable)
+            EnvVar cachePushEnv = new EnvVar();
+            cachePushEnv.setName("GRADLE_REMOTE_CACHE_PUSH");
+            cachePushEnv.setValue("true");
+            container.getEnv().add(cachePushEnv);
+
+            LOGGER.info(formatLogMessage(correlationId,
+                    "Gradle remote cache ENABLED. URL: " + arguments.getCacheUrl()));
+        } else {
+            LOGGER.info(formatLogMessage(correlationId, "Gradle remote cache DISABLED"));
+        }
+    }
+
     /* ------------------- Addition of env vars to Deployments ------------------ */
     public static void addCustomEnvVarsToDeploymentFromSession(String correlationId, Deployment deployment,
             Session session, AppDefinition appDefinition) {

java/operator/org.eclipse.theia.cloud.operator/src/main/java/org/eclipse/theia/cloud/operator/handler/session/EagerSessionHandler.java

@@ -162,6 +162,18 @@ public boolean sessionAdded(Session session, String correlationId) {
             return false;
         }
 
+        // If caching is enabled, ensure per-session gradle.properties is created and mounted into the deployment
+        try {
+
+            client.kubernetes().apps().deployments().withName(deploymentName).edit(deployment -> {
+                AddedHandlerUtil.configureGradleCaching(correlationId, deployment, appDefinition.get(), arguments);
+                return deployment;
+            });
+        } catch (KubernetesClientException e) {
+            LOGGER.warn(formatLogMessage(correlationId, "Could not add gradle init config to deployment " + deploymentName), e);
+            // non-fatal: continue
+        }
+
         if (arguments.isUseKeycloak()) {
             /* add user to allowed emails */
             try {

java/operator/org.eclipse.theia.cloud.operator/src/main/java/org/eclipse/theia/cloud/operator/handler/session/LazySessionHandler.java

@@ -469,8 +469,11 @@ protected void createAndApplyDeployment(String correlationId, String sessionReso
                             appDefinition.getSpec().getUplinkLimit(), correlationId);
                     AddedHandlerUtil.removeEmptyResources(deployment);
 
-                    AddedHandlerUtil.addCustomEnvVarsToDeploymentFromSession(correlationId, deployment, session,
-                            appDefinition);
+            AddedHandlerUtil.addCustomEnvVarsToDeploymentFromSession(correlationId, deployment, session,
+                appDefinition);
+
+            // If operator caching is enabled and a cache URL is configured, add per-session gradle properties
+            AddedHandlerUtil.configureGradleCaching(correlationId, deployment, appDefinition, arguments);
 
                     if (appDefinition.getSpec().getPullSecret() != null
                             && !appDefinition.getSpec().getPullSecret().isEmpty()) {