Add MQTT- and HTTP-based telemetry with JSON encoding

CHANGES.rst

@@ -0,0 +1,27 @@
+#####################
+ISEMS-ESP32 changelog
+#####################
+
+
+Development
+===========
+- Add dry-dock environment.
+- Add MQTT- and HTTP-based telemetry with JSON encoding.
+
+
+2020-01-09 0.0.0
+================
+- Add the full set of LUA files to run the new hardware board.
+- Fix temperature sensor detection and battery charge state estimatation bugs.
+- Cleanup debugging statements.
+
+
+2019-12-03 0.0.0
+================
+- Add preliminary version of ISEMS-ESP32 for external module.
+
+
+2019-10-07 0.0.0
+================
+- Initial commit.
+- Add README.

LUA/ff-esp32-openmppt/config.lua

@@ -10,6 +10,9 @@ long = 13.404954
 
 -- Node-ID
 nodeid="ESP32-Meshnode-1"
+-- The telemetry channel to send metrics to.
+-- See also MQTT and HTTP configuration below.
+telemetry_channel = "isems/testdrive/foobar/" .. nodeid
 
 -- Rated capacity of battery in Ampere hours (Ah)
 rated_batt_capacity = 8.0
@@ -54,3 +57,12 @@ sta_ssid="AP2.freifunk.net"
 
 -- WPA key to connect to the existing AP as WiFi client
 sta_pwd=""
+
+
+-- Telemetry configuration for MQTT and HTTP
+mqtt_enabled = false
+mqtt_broker = "isems.mqtthub.net"
+mqtt_topic = telemetry_channel
+
+http_enabled = false
+http_endpoint = "http://isems.mqtthub.net/api-notls/" .. telemetry_channel .. "/data.json"

LUA/ff-esp32-openmppt/mp2.lua

@@ -501,7 +501,7 @@ statuscode = (bin2hextable[bit_string_0] .. bin2hextable[bit_string_1] .. bin2he
 print("statuscode =", statuscode)
 
 
--- Create CSV data set
+-- CSV payload
 
 timestamp = time.get()
 
@@ -511,7 +511,7 @@ print(nodeid, packetrev, timestamp, firmware_type, nextreboot, powersave, V_oc,
 
 ffopenmppt_log = nodeid .. ";" .. packetrev .. ";" .. timestamp .. ";" .. firmware_type .. ";" .. nextreboot .. ";" .. powersave .. ";".. V_oc .. ";".. V_in .. ";".. V_out .. ";".. charge_state_int .. ";" .. health_estimate .. ";".. battery_temperature .. ";".. low_voltage_disconnect .. ";".. V_out_max_temp .. ";" .. rated_batt_capacity .. ";".. solar_module_capacity .. ";".. lat .. ";" .. long .. ";" ..  statuscode
 
-print(ffopenmppt_log)
+print("CSV payload:", ffopenmppt_log)
 
 if ffopenmppt_log5 ~= nil then 
        ffopenmppt_log1 = ffopenmppt_log2
@@ -531,8 +531,12 @@ if ffopenmppt_log5 ~= nil then
 
        elseif ffopenmppt_log1 == nil then ffopenmppt_log1 = ffopenmppt_log csvlog = ffopenmppt_log1
 
-        end
-
+end
+
+-- HTTP- and MQTT telemetry
+dofile "telemetry.lua"
+
+-- HTML output
         pagestring = "HTTP/1.0 200 OK\r\nContent-Type: text/html\r\n\r\n<h1>Independent Solar Energy Mesh</h1><br><h2>Status of " .. nodeid
         pagestring = pagestring  .. " (local node)</h2><br><br>Summary: " .. charge_status  .. ". " .. system_status
         pagestring = pagestring  .. "<br>Charge state: " 

LUA/ff-esp32-openmppt/telemetry.lua

@@ -0,0 +1,114 @@
+--[[
+Telemetry implementation for MQTT and HTTP.
+]]
+
+function get_telemetry_data()
+    --[[
+    Collect all metric values from global variables
+    and bundle them into a single telemetry data container.
+
+    Note: This might well be improved but for now it's better than nothing.
+    ]]
+    data = {
+        nodeId = nodeid,
+        isemsRevision = packetrev,
+        timestamp = timestamp,
+        timeToShutdown = nextreboot,
+        isPowerSaveMode = powersave,
+        openCircuitVoltage = V_oc,
+        mppVoltage = V_in,
+        batteryVoltage = V_out,
+        batteryChargeEstimate = charge_state_int,
+        batteryHealthEstimate = health_estimate,
+        batteryTemperature = battery_temperature,
+        lowVoltageDisconnectVoltage = low_voltage_disconnect,
+        temperatureCorrectedVoltage = V_out_max_temp,
+        rateBatteryCapacity = rated_batt_capacity,
+        ratedSolarModuleCapacity = solar_module_capacity,
+        latitude = lat,
+        longitude = long,
+        status = statuscode,
+    }
+    return data
+end
+
+function mqtt_publish(data)
+    --[[
+    MQTT telemetry
+
+    Encode telemetry data as JSON and publish message to
+    MQTT broker at topic configured within "config.lua".
+    ]]
+
+    print("Submitting telemetry data to MQTT broker.")
+
+    -- JSON payload
+    -- https://nodemcu.readthedocs.io/en/master/modules/sjson/
+    -- https://github.com/ISEMS/isems-data-collector/blob/926eb4a3/test_importer.py
+    print("Creating JSON payload.")
+    sjson.encode(data)
+    ok, json = pcall(sjson.encode, data)
+    if ok then
+        print("JSON payload:", json)
+    else
+        print("ERROR: Encoding to JSON failed!")
+        return
+    end
+
+    -- https://nodemcu.readthedocs.io/en/master/modules/mqtt/
+    m = mqtt.Client("isems-" .. nodeid, 120)
+    m:connect(mqtt_broker, 1883, 0,
+        function(client)
+            print("Connected to MQTT broker.")
+            client:publish(mqtt_topic, "hello", 0, 0, function(client) print("MQTT message sent.") end)
+        end,
+        function(client, reason)
+            print("MQTT connect failed. Reason: " .. reason)
+        end
+    )
+
+end
+
+function http_post(data)
+    --[[
+    HTTP telemetry
+
+    Encode telemetry data as JSON and send as POST request
+    to HTTP endpoint configured within "config.lua".
+    ]]
+
+    print("Submitting telemetry data to HTTP endpoint.")
+
+    -- JSON payload
+    -- https://nodemcu.readthedocs.io/en/master/modules/sjson/
+    -- https://github.com/ISEMS/isems-data-collector/blob/926eb4a3/test_importer.py
+    print("Creating JSON payload.")
+    ok, json = pcall(sjson.encode, data)
+    if ok then
+        print("JSON payload:", json)
+    else
+        print("ERROR: Encoding to JSON failed!")
+        return
+    end
+
+    -- https://nodemcu.readthedocs.io/en/master/modules/http/
+    http.post(http_endpoint,
+      'Content-Type: application/json\r\n',
+      json,
+      function(code, data)
+        if (code < 0) then
+          print("HTTP request failed", code, data)
+        else
+          print("HTTP request succeeded", code, data)
+        end
+      end)
+
+end
+
+if mqtt_enabled == true then
+    mqtt_publish(get_telemetry_data())
+end
+
+if http_enabled == true then
+    http_post(get_telemetry_data())
+end

LUA/ff-esp32-openmppt/test/README.rst

@@ -0,0 +1,14 @@
+####################
+ISEMS-ESP32 dry-dock
+####################
+
+About
+=====
+This environment makes it possible to run parts of the
+ISEMS-ESP32 Node MCU Lua code on a vanilla PC.
+
+Synopsis
+========
+::
+
+	lua test/run_basic.lua

LUA/ff-esp32-openmppt/test/nodemcu_mock.lua

@@ -0,0 +1,64 @@
+--[[
+Mock the API of a NodeMCU device.
+]]
+
+
+--[[
+Mocks for NodeMCU core modules.
+]]
+time = {
+    get = function()
+        return os.time()
+    end,
+    getlocal = function()
+        date = os.date("*t")
+        date["mon"] = date["month"]
+        date["dst"] = "1"
+        return date
+    end,
+}
+
+node = {
+    dsleep = function() end,
+}
+
+file = {
+    list = function() end,
+    exists = function() end,
+}
+
+gpio = {
+    config = function() end,
+    wakeup = function() end,
+    write = function() end,
+}
+
+dac = {
+    enable = function() end,
+}
+
+adc = {
+    setup = function() end,
+    setwidth = function() end,
+    read = function() return 42.42 end,
+}
+
+
+--[[
+Requires nodemcu-lua-mocks to be installed for JSON support.
+https://github.com/fikin/nodemcu-lua-mocks
+]]
+
+local sjson = require("sjson")
+sjson.encode = function(data)
+    encoder = sjson.encoder(data)
+    return encoder:read(8192)
+end
+
+
+--[[
+TODO: Add mocks for mqtt and http modules.
+Currently, "test/run_basic" will croak with::
+
+    lua: telemetry.lua:59: attempt to index a nil value (global 'mqtt')
+]]

LUA/ff-esp32-openmppt/test/run_basic.lua

@@ -0,0 +1,14 @@
+--[[
+Run a single duty cycle to completion.
+]]
+
+-- Bootstrap
+dofile "test/nodemcu_mock.lua"
+dofile "config.lua"
+
+-- No periodic execution.
+-- dofile "is.lua"
+
+-- Run cycle.
+Vref = 1100 --mV
+dofile "mp2.lua"