data/edge5cdab/modbus & logging

app/src/handlers/edge5cdab-modbus.ts

@@ -0,0 +1,68 @@
+import { postCloudIngest } from '../cloud-ingest.js'
+import { log } from '../helpers/log.js'
+import type { TopicHandler } from '../types.js'
+
+const EDGE = 'edge5cdab'
+const REGISTER_COUNT = 100
+
+type Edge5iiModbusMetric = {
+  edge: string
+  timestamp: string
+  tag: string
+  value: number
+}
+
+function toFloatCDAB(reg0: number, reg1: number): number {
+  const buf = Buffer.allocUnsafe(4)
+  buf.writeUInt16BE(reg1, 0)
+  buf.writeUInt16BE(reg0, 2)
+  return buf.readFloatBE(0)
+}
+
+function parseValues(payload: Buffer): number[] {
+  const values = JSON.parse(payload.toString('utf8')) as number[]
+  assertRegisterCount(values)
+  return values
+}
+
+function assertRegisterCount(values: number[]): void {
+  if (values.length !== REGISTER_COUNT) {
+    throw new Error(`Expected ${REGISTER_COUNT} modbus values, got ${values.length}`)
+  }
+}
+
+function toMetrics(values: number[], timestamp: string): Edge5iiModbusMetric[] {
+  const metrics: Edge5iiModbusMetric[] = []
+
+  for (let i = 0; i < values.length; i += 2) {
+    metrics.push({
+      edge: EDGE,
+      timestamp,
+      tag: `register-${String(i).padStart(3, '0')}`,
+      value: toFloatCDAB(values[i], values[i + 1]),
+    })
+  }
+
+  return metrics
+}
+
+async function postMetrics(metrics: Edge5iiModbusMetric[]): Promise<void> {
+  for (const metric of metrics) {
+    const response = await postCloudIngest(metric)
+
+    if (!response.ok) {
+      const text = await response.text()
+      throw new Error(text)
+    }
+  }
+
+  log(`${EDGE}.modbus.posted ${metrics.length} metrics`)
+}
+
+export const handle: TopicHandler = async (topic, payload) => {
+  log(`${EDGE}.modbus.received ${topic} ${payload.length} bytes`)
+
+  const values = parseValues(payload)
+  const metrics = toMetrics(values, new Date().toISOString())
+  await postMetrics(metrics)
+}