From f703ae2fd1cf7f79d8f17e2526df7293de5e2514 Mon Sep 17 00:00:00 2001
From: Daniel Friesel <derf@finalrewind.org>
Date: Sun, 15 May 2022 21:47:18 +0200
Subject: Add InfluxDB support

---
 README.md | 29 +++++++++++++++++++++--------
 init.lua  | 43 ++++++++++++++++++++++++++++++-------------
 2 files changed, 51 insertions(+), 21 deletions(-)

diff --git a/README.md b/README.md
index 029f329..b38159c 100644
--- a/README.md
+++ b/README.md
@@ -56,14 +56,6 @@ function uart_callback(data)
 end
 ```
 
-See **init.lua** for an example. To use it, you need to create a **config.lua** file with WiFI and MQTT settings:
-
-```lua
-station_cfg.ssid = "..."
-station_cfg.pwd = "..."
-mqtt_host = "..."
-```
-
 ## SDS011 Configuration API
 
 If desired, **sds011.lua** can be used to configure the SDS011 sensor.
@@ -78,3 +70,24 @@ Currently, the following commands are supported
 * `port:write(sds011.set_work_period(period))`
   * period == 0: continuous operation (about one measurement per second)
   * 0 < *period* ≤ 30: about one measurement every *period* minutes; fan turned off in-between
+
+## Application Example
+
+**init.lua** is an example application with HomeAssistant integration.
+To use it, you need to create a **config.lua** file with WiFI and MQTT settings:
+
+```lua
+station_cfg.ssid = "..."
+station_cfg.pwd = "..."
+mqtt_host = "..."
+```
+
+Optionally, it can also publish readings to an InfluxDB.
+To do so, configure URL and attribute:
+
+```lua
+influx_url = "..."
+influx_attr = "..."
+```
+
+Readings will be stored as `sds011,[influx_attr] pm2_5_ugm3=...,pm10_ugm3=...`
diff --git a/init.lua b/init.lua
index 143669a..51aeafc 100644
--- a/init.lua
+++ b/init.lua
@@ -1,12 +1,15 @@
 station_cfg = {}
-dofile("config.lua")
+publishing_mqtt = false
+publishing_http = false
 
-delayed_restart = tmr.create()
+watchdog = tmr.create()
 chip_id = string.format("%06X", node.chipid())
 device_id = "esp8266_" .. chip_id
 mqtt_prefix = "sensor/" .. device_id
 mqttclient = mqtt.Client(device_id, 120)
 
+dofile("config.lua")
+
 print("ESP8266 " .. chip_id)
 
 ledpin = 4
@@ -16,16 +19,15 @@ gpio.write(ledpin, 0)
 sds011 = require("sds011")
 
 function log_restart()
-	print("Network error " .. wifi.sta.status() .. ". Restarting in 20 seconds.")
-	delayed_restart:start()
+	print("Network error " .. wifi.sta.status())
 end
 
 function setup_client()
 	print("Connected")
 	gpio.write(ledpin, 1)
-	publishing = true
+	publishing_mqtt = true
 	mqttclient:publish(mqtt_prefix .. "/state", "online", 0, 1, function(client)
-		publishing = false
+		publishing_mqtt = false
 	end)
 	port = softuart.setup(9600, 2, 1)
 	port:on("data", 10, uart_callback)
@@ -63,11 +65,28 @@ function uart_callback(data)
 		work_period = string.format("%d min", sds011.work_period)
 	end
 	local json_str = string.format('{"pm2_5_ugm3": %d.%d, "pm10_ugm3": %d.%d, "rssi_dbm": %d, "period": "%s"}', pm25i, pm25f, pm10i, pm10f, wifi.sta.getrssi(), work_period)
-	if not publishing then
-		publishing = true
+	local influx_str = string.format("pm2_5_ugm3=%d.%d,pm10_ugm3=%d.%d", pm25i, pm25f, pm10i, pm10f)
+	if not publishing_mqtt then
+		watchdog:start(true)
+		publishing_mqtt = true
 		gpio.write(ledpin, 0)
 		mqttclient:publish(mqtt_prefix .. "/data", json_str, 0, 0, function(client)
-			publishing = false
+			publishing_mqtt = false
+			if influx_url and influx_attr and influx_str then
+				publish_influx(influx_str)
+			else
+				gpio.write(ledpin, 1)
+				collectgarbage()
+			end
+		end)
+	end
+end
+
+function publish_influx(payload)
+	if not publishing_http then
+		publishing_http = true
+		http.post(influx_url, influx_header, "sds011" .. influx_attr .. " " .. payload, function(code, data)
+			publishing_http = false
 			gpio.write(ledpin, 1)
 			collectgarbage()
 		end)
@@ -93,8 +112,6 @@ function hass_register()
 	local hass_rssi = string.format('{%s,"name":"RSSI","object_id":"%s_rssi","unique_id":"%s_rssi","device_class":"signal_strength","unit_of_measurement":"dBm","value_template":"{{value_json.rssi_dbm}}","entity_category":"diagnostic"}', hass_entity_base, device_id, device_id)
 	local hass_period = string.format('{%s,"name":"Measurement Period","object_id":"%s_period","unique_id":"%s_period","icon":"mdi:clock-outline","command_topic":"config/%s/set/work_period","options":["continuous","1 min","2 min","3 min","4 min","5 min","6 min","7 min","8 min","9 min","10 min"],"value_template":"{{value_json.period}}","entity_category":"config"}', hass_entity_base, device_id, device_id, device_id)
 
-	delayed_restart:stop()
-
 	mqttclient:publish("homeassistant/sensor/" .. device_id .. "/pm2_5/config", hass_pm2_5, 0, 1, function(client)
 		mqttclient:publish("homeassistant/sensor/" .. device_id .. "/pm10/config", hass_pm10, 0, 1, function(client)
 			mqttclient:publish("homeassistant/sensor/" .. device_id .. "/rssi/config", hass_rssi, 0, 1, function(client)
@@ -109,7 +126,7 @@ function hass_register()
 	end)
 end
 
-delayed_restart:register(30 * 1000, tmr.ALARM_SINGLE, node.restart)
-delayed_restart:start()
+watchdog:register(20 * 60 * 1000, tmr.ALARM_SEMI, node.restart)
+watchdog:start()
 
 connect_wifi()
-- 
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