From 2bc7f22198ba4b21db501d00f1924b3211273194 Mon Sep 17 00:00:00 2001
From: Christian Pointner <equinox@spreadspace.org>
Date: Wed, 28 Sep 2022 16:30:24 +0200
Subject: import some stuff from helsinki ansible

---
 .../openwrt/gpsd_prometheus-node-exporter.lua      | 138 +++++++++++++++++++++
 1 file changed, 138 insertions(+)
 create mode 100644 files/common/openwrt/gpsd_prometheus-node-exporter.lua

(limited to 'files')

diff --git a/files/common/openwrt/gpsd_prometheus-node-exporter.lua b/files/common/openwrt/gpsd_prometheus-node-exporter.lua
new file mode 100644
index 00000000..b7ed92f1
--- /dev/null
+++ b/files/common/openwrt/gpsd_prometheus-node-exporter.lua
@@ -0,0 +1,138 @@
+local socket = require "socket"
+local cjson = require "cjson.safe"
+
+local last_error_msg = {}
+local last_watch_msg = {}
+local last_devices_msg = {}
+
+function gpsd_setup()
+    local s, err = socket.tcp4()
+    if err ~= nil then return nil, err end
+    s:settimeout(1)
+
+    _, err = s:connect('127.0.0.1', 2947)
+    if err ~= nil then return nil, err end
+
+    local msg_json, err = s:receive('*l')
+    if err ~= nil then
+        s:close()
+        return nil, err
+    end
+
+    local msg, err = cjson.decode(msg_json)
+    if err ~= nil then
+        s:close()
+        return nil, err
+    end
+    if msg['class'] ~= 'VERSION' then
+        s:close()
+        return nil, "got unexpected message class from GPSD: " .. tostring(msg['class'])
+    end
+
+    _, err = s:send('?WATCH={"enable":"true"}')
+    if err ~= nil then
+        s:close()
+        return nil, err
+    end
+
+    return s, msg
+end
+
+function gpsd_poll(s)
+    _, err = s:send('?DEVICES;')
+    if err ~= nil then
+        s:close()
+        return nil, err
+    end
+    _, err = s:send('?POLL;')
+    if err ~= nil then
+        s:close()
+        return nil, err
+    end
+
+    while true do
+        local msg_json, err = s:receive('*l')
+        if err ~= nil then
+            s:close()
+            return nil, err
+        end
+
+        local msg, err = cjson.decode(msg_json)
+        if err ~= nil then
+            s:close()
+            return nil, err
+        end
+
+        if msg['class'] == 'ERROR' then
+            last_error_msg = msg
+        elseif msg['class'] == 'WATCH' then
+            last_watch_msg = msg
+        elseif msg['class'] == 'DEVICES' then
+            last_devices_msg = msg
+        elseif msg['class'] == 'POLL' then
+            return s, msg
+        else
+            print("ignoring unknown message class from GPSD: " .. tostring(msg['class']))
+        end
+    end
+end
+
+function metric_version_info(version_info)
+    local labels = {}
+    labels['rev'] = version_info['rev']
+    labels['release'] = version_info['release']
+    labels['proto_major'] = version_info['proto_major']
+    labels['proto_minor'] = version_info['proto_minor']
+
+    metric("gpsd_version_info", "gauge", labels, 1)
+end
+
+function metric_devices(devices_msg)
+    if devices_msg['devices'] == nil then return end
+    for _, dev in ipairs(devices_msg['devices']) do
+        local labels = {}
+        labels['device'] = dev['path']
+        labels['driver'] = dev['driver']
+        labels['subtype'] = dev['subtype']
+        labels['subtype1'] = dev['subtype1']
+
+        metric("gpsd_device_info", "gauge", labels, 1)
+    end
+end
+
+function metric_poll(poll_msg)
+    for _, tpv in ipairs(poll_msg['tpv']) do
+        local labels = {}
+        labels['device'] = tpv['device']
+
+        metric("gpsd_tpv_mode", "gauge", labels, tpv['mode'])
+        if tpv['alt'] ~= nil then
+            metric("gpsd_tpv_altitude_meters", "gauge", labels, tpv['alt'])
+        end
+        if tpv['lat'] ~= nil then
+            metric("gpsd_tpv_latitude_degrees", "gauge", labels, tpv['lat'])
+        end
+        if tpv['lon'] ~= nil then
+            metric("gpsd_tpv_longitude_degrees", "gauge", labels, tpv['lon'])
+        end
+    end
+end
+
+local s, version_info = gpsd_setup()
+
+local function scrape()
+    if s == nil then
+        print("lost connection to gpsd, reconncting...")
+        s, version_info = gpsd_setup()
+        if s == nil then return s, version_info end
+    end
+    metric_version_info(version_info)
+
+    s, poll_msg = gpsd_poll(s)
+    if s == nil then return s, poll end
+
+    metric_devices(last_devices_msg)
+    metric_poll(poll_msg)
+end
+
+return { scrape = scrape }
-- 
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