From 060063f2d428903c073036876dad6dc6195576aa Mon Sep 17 00:00:00 2001
From: Daniel Friesel <derf@finalrewind.org>
Date: Sun, 15 May 2022 21:34:47 +0200
Subject: Add InfluxDB support

---
 README.md | 14 +++++++++++++-
 init.lua  | 48 +++++++++++++++++++++++++++++++++---------------
 2 files changed, 46 insertions(+), 16 deletions(-)

diff --git a/README.md b/README.md
index e592ccb..e37a46e 100644
--- a/README.md
+++ b/README.md
@@ -45,11 +45,23 @@ function uart_callback(data)
 	end
 end
 ```
+## Application Example
 
-See **init.lua** for an example. To use it, you need to create a **config.lua** file with WiFI and MQTT settings:
+**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:
+
+```
+influx_url = "..."
+influx_attr = "..."
+```
+
+Readings will be stored as `vindriktning,[influx_attr] pm2_5_ugm3=...`
diff --git a/init.lua b/init.lua
index f5b19ee..35d87e9 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
@@ -18,16 +21,15 @@ pm1006 = require("pm1006")
 pm_values = {}
 
 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, nil, 2)
 	port:on("data", 20, uart_callback)
@@ -37,6 +39,7 @@ function connect_mqtt()
 	print("IP address: " .. wifi.sta.getip())
 	print("Connecting to MQTT " .. mqtt_host)
 	mqttclient:on("connect", hass_register)
+	mqttclient:on("connfail", log_restart)
 	mqttclient:on("offline", log_restart)
 	mqttclient:lwt(mqtt_prefix .. "/state", "offline", 0, 1)
 	mqttclient:connect(mqtt_host)
@@ -68,28 +71,43 @@ function uart_callback(data)
 			local pm_int = pm_sum / 10
 			local pm_frac = pm_sum % 10
 			local json_str = string.format('{"pm2_5_ugm3": %d.%d, "rssi_dbm": %d}', pm_int, pm_frac, wifi.sta.getrssi())
+			local influx_str = string.format("pm2_5_ugm3=%d.%d", pm_int, pm_frac)
 			pm_values = {}
-			if not publishing then
-				publishing = true
+			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
-					gpio.write(ledpin, 1)
-					collectgarbage()
+					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
 	end
 end
 
+function publish_influx(payload)
+	if not publishing_http then
+		publishing_http = true
+		http.post(influx_url, influx_header, "vindriktning" .. influx_attr .. " " .. payload, function(code, data)
+			publishing_http = false
+			gpio.write(ledpin, 1)
+			collectgarbage()
+		end)
+	end
+end
+
 function hass_register()
 	local hass_device = string.format('{"connections":[["mac","%s"]],"identifiers":["%s"],"model":"ESP8266 + PM1006","name":"Vindriktning %s","manufacturer":"derf"}', wifi.sta.getmac(), device_id, chip_id)
 	local hass_entity_base = string.format('"device":%s,"state_topic":"%s/data","expire_after":90', hass_device, mqtt_prefix)
 	local hass_pm2_5 = string.format('{%s,"name":"PM2.5","object_id":"%s_pm2_5","unique_id":"%s_pm2_5","device_class":"pm25","unit_of_measurement":"µg/m³","value_template":"{{value_json.pm2_5_ugm3}}"}', hass_entity_base, device_id, device_id)
 	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)
 
-	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 .. "/rssi/config", hass_rssi, 0, 1, function(client)
 			collectgarbage()
@@ -98,7 +116,7 @@ function hass_register()
 	end)
 end
 
-delayed_restart:register(30 * 1000, tmr.ALARM_SINGLE, node.restart)
-delayed_restart:start()
+watchdog:register(120 * 1000, tmr.ALARM_SEMI, node.restart)
+watchdog:start()
 
 connect_wifi()
-- 
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