From 7d8ac22bb17fed78f15adf8b6de1bf246ef28892 Mon Sep 17 00:00:00 2001
From: Andre Kully <akully@gmx.net>
Date: Thu, 23 Dec 2021 16:46:18 +0100
Subject: [PATCH] use stringer to generate enum type

---
 Makefile | 18 +++++++++++++-----
 main.go  | 27 ++++++++++++++++++++-------
 2 files changed, 33 insertions(+), 12 deletions(-)

diff --git a/Makefile b/Makefile
index 365589e..3d3d494 100644
--- a/Makefile
+++ b/Makefile
@@ -1,6 +1,7 @@
 ##
 #
 .DEFAULT_GOAL := help
+.PHONY: generate
 
 version    := $(shell git describe --tags --always)
 revision   := $(shell git rev-parse HEAD)
@@ -18,17 +19,24 @@ LDFLAGS   := -w -s \
 	-X $(versionPkgPrefix).BuildDate=${builddate}
 GOFLAGS   := -v
 
-linux: ## builds the linux version of the exporter
+linux: generate ## builds the linux version of the exporter
 	GOOS=linux GOARCH=amd64 go build $(GOFLAGS) -ldflags '$(LDFLAGS)'
-mac: ## builds the macos version of the exporter
+mac: generate ## builds the macos version of the exporter
 	GOOS=darwin GOARCH=amd64 go build $(GOFLAGS) -ldflags '$(LDFLAGS)'
-mac-arm: ## builds the macos (m1) version of the exporter
+mac-arm: generate ## builds the macos (m1) version of the exporter
 	GOOS=darwin GOARCH=arm64 go build $(GOFLAGS) -ldflags '$(LDFLAGS)'
-arm64:
+arm64: generate
 	GOOS=linux GOARCH=arm64 go build $(GOFLAGS) -ldflags '$(LDFLAGS)'
-arm:
+arm: generate
 	GOOS=linux GOARCH=arm go build $(GOFLAGS) -ldflags '$(LDFLAGS)'
 
+# -- see more info on https://pkg.go.dev/golang.org/x/tools/cmd/stringer
+generate: $(GOPATH)/bin/stringer
+	go generate ./...
+
+$(GOPATH)/bin/stringer:
+	go install golang.org/x/tools/cmd/stringer@latest
+
 # --
 help:
 	@grep -E '^[a-zA-Z_-]+:.*?## .*$$' $(MAKEFILE_LIST)  | sort | awk 'BEGIN {FS = ":.*?## "}; {printf "\033[36m%-30s\033[0m %s\n", $$1, $$2}'
diff --git a/main.go b/main.go
index fd58ca8..dc8ae82 100644
--- a/main.go
+++ b/main.go
@@ -1,3 +1,4 @@
+//go:generate stringer -type MystromReqStatus main.go
 package main
 
 import (
@@ -16,14 +17,15 @@ import (
 	"mystrom-exporter/pkg/version"
 )
 
-type switchReport struct {
-	Power       float64 `json:"power"`
-	WattPerSec  float64 `json:"Ws"`
-	Relay       bool    `json:"relay"`
-	Temperature float64 `json:"temperature"`
-}
+// -- MystromRequestStatusType represents the request to MyStrom device status
+type MystromReqStatus uint32
 
-const namespace = "mystrom"
+const (
+	OK MystromReqStatus = iota
+	ERROR_SOCKET
+	ERROR_TIMEOUT
+	ERROR_PARSING_VALUE
+)
 
 var (
 	listenAddress = flag.String("web.listen-address", ":9452",
@@ -66,6 +68,12 @@ func main() {
 	}, []string{"target"})
 	telemetryRegistry.MustRegister(mystromDurationCounterVec)
 
+	mystromRequestsCounterVec = prometheus.NewCounterVec(prometheus.CounterOpts{
+		Name: "mystrom_requests_total",
+		Help: "Number of mystrom request by status and target",
+	}, []string{"target", "status"})
+	telemetryRegistry.MustRegister(mystromRequestsCounterVec)
+
 	// -- make the build information is available through a metric
 	buildInfo := prometheus.NewGaugeVec(
 		prometheus.GaugeOpts{
@@ -115,7 +123,11 @@ func scrapeHandler(e *mystrom.Exporter, w http.ResponseWriter, r *http.Request)
 	duration := time.Since(start).Seconds()
 	if err != nil {
 		if strings.Contains(fmt.Sprintf("%v", err), "unable to connect with target") {
+			mystromRequestsCounterVec.WithLabelValues(target, ERROR_SOCKET.String()).Inc()
 		} else if strings.Contains(fmt.Sprintf("%v", err), "i/o timeout") {
+			mystromRequestsCounterVec.WithLabelValues(target, ERROR_TIMEOUT.String()).Inc()
+		} else {
+			mystromRequestsCounterVec.WithLabelValues(target, ERROR_PARSING_VALUE.String()).Inc()
 		}
 		http.Error(
 			w,
@@ -126,6 +138,7 @@ func scrapeHandler(e *mystrom.Exporter, w http.ResponseWriter, r *http.Request)
 		return
 	}
 	mystromDurationCounterVec.WithLabelValues(target).Add(duration)
+	mystromRequestsCounterVec.WithLabelValues(target, OK.String()).Inc()
 
 	promhttp.HandlerFor(gatherer, promhttp.HandlerOpts{}).ServeHTTP(w, r)