Add support for retain flag on sensor values (#153)

* Add support for retain flag on sensor values
Fixes #152

* Update src/mqttManager.ts

* Update changelog

CHANGELOG.md

@@ -1,8 +1,12 @@
 # Version
 
+## 4.6.0
+
+* Add retain flag for `lastRain` sensor and new environment variable for enabling retain of all sensor values. (Fixes [#152](https://github.com/neilenns/ambientweather2mqtt/issues/152))
+
 ## 4.5.1
 
-* Remove bashio calls from HomeAssistant add-on. (Fixes [[#147](https://github.com/neilenns/ambientweather2mqtt/issues/147)])
+* Remove bashio calls from HomeAssistant add-on. (Fixes [#147](https://github.com/neilenns/ambientweather2mqtt/issues/147))
 
 ## 4.5.0
 

hassio_aw2m/config.yaml

@@ -15,6 +15,7 @@ options:
   STATION_MAC_ADDRESS: "00:00:00:00:00:00"
   TZ: "America/Los_Angeles"
   LOG_LEVEL: "info"
+  RETAIN_SENSOR_VALUES: false
 schema:
   MQTT_SERVER: "url"
   MQTT_USERNAME: "str"
@@ -23,6 +24,7 @@ schema:
   STATION_MAC_ADDRESS: "str"
   TZ: "str"
   LOG_LEVEL: list(error|warn|info|http|debug)
+  RETAIN_SENSOR_VALUES: "bool"
 services:
   - "mqtt:need"
 arch:

src/entity.ts

@@ -8,6 +8,7 @@ import DeviceClass from "./deviceClass.js";
 import EntityCategory from "./entityCategory.js";
 import EntityDataPayload from "./entityDataPayload.js";
 import EntityDiscoveryPayload from "./entityDiscoveryPayload.js";
+import env from "./env.js";
 import mainLogger from "./log.js";
 import * as mqttManager from "./mqttManager.js";
 import SensorUnit from "./sensorUnit.js";
@@ -25,6 +26,7 @@ export default class Entity {
   public availabilityTopic: string;
   public value: EntityDataPayload;
   public discoveryPayload: EntityDiscoveryPayload;
+  public retain: boolean;
 
   private deviceId: string;
 
@@ -36,6 +38,7 @@ export default class Entity {
    * @param deviceClass The device class for the sensor. Optional.
    * @param icon The mdi icon for the sensor. Optional.
    * @param entityCategory The Home Assistant entity category for the sensor. Optional.
+   * @param retain True if the MQTT data topic should be sent with the retain flag set to true. Optional, default false.
    */
   constructor(
     name: string,
@@ -44,8 +47,10 @@ export default class Entity {
     deviceClass?: DeviceClass,
     icon?: string,
     entityCategory?: EntityCategory,
+    retain = false,
   ) {
     this.deviceId = deviceId;
+    this.retain = retain;
 
     this.discoveryPayload = {
       device: {
@@ -103,7 +108,7 @@ export default class Entity {
       return mqttManager.publish(this.stateTopic, this.value.toUTCString());
     }
 
-    return mqttManager.publish(this.stateTopic, this.value.toString());
+    return mqttManager.publish(this.stateTopic, this.value.toString(), this.retain || env().RETAIN_SENSOR_VALUES);
   }
 
   /**

src/entityManager.ts

@@ -577,7 +577,7 @@ export function initialize(): void {
   );
   entities.set(
     EntityNames.LASTRAIN,
-    new Sensor(EntityNames.LASTRAIN, deviceId, undefined, DeviceClass.TIMESTAMP, "clock-outline"),
+    new Sensor(EntityNames.LASTRAIN, deviceId, undefined, DeviceClass.TIMESTAMP, "clock-outline", undefined, true),
   );
   entities.set(
     EntityNames.DEWPOINT1,

src/env.ts

@@ -31,6 +31,7 @@ const envSchema = z.object({
   TZ: z.string().default("America/Los_Angeles"),
   TOPIC_ROOT: z.string().optional(),
   NODE_ENV: z.string().default("production"),
+  RETAIN_SENSOR_VALUES: z.string().transform<boolean>(booleanTransformer).default("false"),
 });
 
 let parsedEnv: z.infer<typeof envSchema>;

src/mqttManager.ts

@@ -50,7 +50,7 @@ export async function publish(topic: string, data: string, retain?: boolean): Pr
     return;
   }
 
-  logger.debug(`Publishing ${data} to ${topic}`, { data, topic });
+  logger.debug(`Publishing ${data} to ${topic} with retain: ${retain}`, { data, topic, retain });
   return client.publish(topic, data, { retain });
 }
 

src/sensor.ts

@@ -29,8 +29,9 @@ export default class Sensor extends Entity {
     deviceClass?: DeviceClass,
     icon?: string,
     entityCategory?: EntityCategory,
+    retain = false,
   ) {
-    super(name, deviceId, unit, deviceClass, icon, entityCategory);
+    super(name, deviceId, unit, deviceClass, icon, entityCategory, retain);
 
     this.discoveryTopic = `${TopicRoot}/sensor/${deviceId}/${this.discoveryPayload.name}/config`;
     this.stateTopic = `${TopicRoot}/sensor/${deviceId}/${this.discoveryPayload.name}/state`;