Deliver Alert Banner data with environment polling (#404)

+ For use with corresponding hoist-react change xh/hoist-react@645cc60

CHANGELOG.md

@@ -19,6 +19,8 @@
 
 ### ⚙️ Technical
 
+* Enhanced the `xh/environmentPoll` payload to include any active Alert Banner spec. Clients running
+  `hoist-react >= 68` will leverage this to avoid an extra polling request.
 * Exposed `/xh/ping` as whitelisted route for basic uptime/reachability checks. Retained legacy
   `/ping` alias, but prefer this new path going forward.
 * Improved handling + rendering of exceptions during authentication and authorization requests.

grails-app/controllers/io/xh/hoist/impl/XhController.groovy

@@ -267,6 +267,9 @@ class XhController extends BaseController {
     //----------------------
     // Alert Banner
     //----------------------
+    /**
+     * @deprecated - used by hoist-react <= 67, now nested within {@link #environmentPoll}.
+     */
     def alertBanner() {
         renderJSON(alertBannerService.alertBanner)
     }

grails-app/init/io/xh/hoist/BootStrap.groovy

@@ -80,10 +80,10 @@ class BootStrap implements LogSupport {
             ],
             xhAlertBannerConfig: [
                 valueType: 'json',
-                defaultValue: [enabled: true, interval: 30],
+                defaultValue: [enabled: true],
                 clientVisible: true,
                 groupName: 'xh.io',
-                note: 'Configures support for showing an app-wide alert banner.\n\nAdmins configure and activate alert banners from the Hoist Admin console. To generally enable this system, set "enabled" to true and "interval" to a positive value (in seconds) to control how often connected apps check for a new alert.'
+                note: 'Configures support for showing an app-wide alert banner.\n\nAdmins configure and activate alert banners from the Hoist Admin console. To generally enable this system, set "enabled" to true. The xhEnvPollConfig.interval config governs client polling for updates.'
             ],
             xhAppInstances: [
                 valueType: 'json',

grails-app/services/io/xh/hoist/alertbanner/AlertBannerService.groovy

@@ -7,7 +7,6 @@
 
 package io.xh.hoist.alertbanner
 
-
 import groovy.transform.CompileStatic
 import io.xh.hoist.BaseService
 import io.xh.hoist.cache.CachedValue
@@ -27,7 +26,9 @@ import static java.lang.System.currentTimeMillis
  *
  * This class uses a single {@link io.xh.hoist.jsonblob.JsonBlob} to persist its state.
  * The published alert state is updated via the Hoist Admin console and is regularly refreshed
- * on a timer to catch banner expiry.
+ * by EnvironmentService.
+ *
+ * For this service to be active, `xhAlertBannerConfig` config must be specified as `{enabled:true}`.
  */
 @CompileStatic
 class AlertBannerService extends BaseService {
@@ -101,10 +102,9 @@ class AlertBannerService extends BaseService {
     // Implementation
     //-----------------------------
     private void readFromSpec() {
-        def conf = configService.getMap('xhAlertBannerConfig'),
-            newSpec = emptyAlert
+        def newSpec = emptyAlert
 
-        if (conf.enabled) {
+        if (configService.getMap('xhAlertBannerConfig').enabled) {
             def spec = getAlertSpec(),
                 expires = spec.expires as Long
 

grails-app/services/io/xh/hoist/environment/EnvironmentService.groovy

@@ -11,24 +11,27 @@ import grails.plugins.GrailsPlugin
 import grails.util.GrailsUtil
 import grails.util.Holders
 import io.xh.hoist.BaseService
+import io.xh.hoist.alertbanner.AlertBannerService
 import io.xh.hoist.config.ConfigService
 import io.xh.hoist.util.Utils
 import io.xh.hoist.websocket.WebSocketService
 
 
 /**
  * Service with metadata describing the runtime environment of Hoist and this application.
- * For the AppEnvironment (e.g. Development/Production), reference `Utils.appEnvironment`.
+ *
+ * If you are simply looking to read the `AppEnvironment` (e.g. Development/Production), use
+ * the static {@link io.xh.hoist.util.Utils#getAppEnvironment} instead.
  */
 class EnvironmentService extends BaseService {
 
     ConfigService configService
     WebSocketService webSocketService
+    AlertBannerService alertBannerService
 
     private TimeZone _appTimeZone
-    private Map _pollResult
 
-    static clearCachesConfigs = ['xhAppTimeZone', 'xhEnvPollConfig']
+    static clearCachesConfigs = ['xhAppTimeZone']
 
     /**
      * Official TimeZone for this application - e.g. the zone of the head office or trading center.
@@ -66,6 +69,7 @@ class EnvironmentService extends BaseService {
                 appTimeZoneOffset:      appTz.getOffset(now),
                 webSocketsEnabled:      webSocketService.enabled,
                 instanceName:           clusterService.instanceName,
+                alertBanner:            alertBannerService.alertBanner,
                 pollConfig:             configService.getMap('xhEnvPollConfig')
         ]
 
@@ -84,16 +88,17 @@ class EnvironmentService extends BaseService {
     }
 
     /**
-     * Report server version and instance identity to the client.
-     * Designed to be called frequently by client. Should be minimal and highly optimized.
+     * Report server version, instance identity, and any active alert banner to the client.
+     * Designed for rapid polling - keep this minimal and highly optimized.
      */
     Map environmentPoll() {
-        return _pollResult ?= [
+        return [
             appCode     : Utils.appCode,
             appVersion  : Utils.appVersion,
             appBuild    : Utils.appBuild,
             instanceName: clusterService.instanceName,
-            pollConfig  : configService.getMap('xhEnvPollConfig'),
+            alertBanner : alertBannerService.alertBanner,
+            pollConfig  : configService.getMap('xhEnvPollConfig')
         ]
     }
 
@@ -119,7 +124,6 @@ class EnvironmentService extends BaseService {
 
     void clearCaches() {
         _appTimeZone = null
-        _pollResult = null
         super.clearCaches()
     }
 }