Merge pull request #72 from LucaBernstein/monitoring

Add monitoring endpoint for app stats

Dockerfile

@@ -24,4 +24,6 @@ WORKDIR /
 
 COPY --from=builder /src/app /bin/app
 
+EXPOSE 8081
+
 ENTRYPOINT [ "/bin/app" ]

db/crud/monitoring.go

@@ -0,0 +1,92 @@
+package crud
+
+import "github.com/LucaBernstein/beancount-bot-tg/helpers"
+
+func (r *Repo) HealthGetLogs(lastHours int) (errors int, warnings int, err error) {
+	rows, err := r.db.Query(`
+		SELECT "level", COUNT(*) "c"
+		FROM "app::log"
+		WHERE "level" IN ($1, $2)
+			AND "created" + INTERVAL '1 hour' * $3 > NOW()
+		GROUP BY "level"`,
+		helpers.ERROR, helpers.WARN, lastHours)
+	if err != nil {
+		return
+	}
+	var (
+		level int
+		count int
+	)
+	for rows.Next() {
+		rows.Scan(&level, &count)
+		switch level {
+		case int(helpers.ERROR):
+			errors = count
+		case int(helpers.WARN):
+			warnings = count
+		}
+	}
+	return
+}
+
+func (r *Repo) HealthGetTransactions() (open int, archived int, err error) {
+	rows, err := r.db.Query(`
+		SELECT "archived", COUNT(*) "c"
+		FROM "bot::transaction"
+		GROUP BY "archived"`)
+	if err != nil {
+		return
+	}
+	var (
+		isArchived bool
+		count      int
+	)
+	for rows.Next() {
+		rows.Scan(&isArchived, &count)
+		if isArchived {
+			archived = count
+		} else {
+			open = count
+		}
+	}
+	return
+}
+
+func (r *Repo) HealthGetUserCount() (count int, err error) {
+	rows, err := r.db.Query(`
+		SELECT COUNT(*) "c"
+		FROM "auth::user"`)
+	if err != nil {
+		return
+	}
+	if rows.Next() {
+		rows.Scan(&count)
+	}
+	return
+}
+
+func (r *Repo) HealthGetCacheStats() (accTo int, accFrom int, txDesc int, err error) {
+	rows, err := r.db.Query(`
+		SELECT "type", COUNT(*) "c"
+		FROM "bot::cache"
+		GROUP BY "type"`)
+	if err != nil {
+		return
+	}
+	var (
+		t     string
+		count int
+	)
+	for rows.Next() {
+		rows.Scan(&t, &count)
+		switch t {
+		case helpers.STX_ACCT:
+			accTo = count
+		case helpers.STX_ACCF:
+			accFrom = count
+		case helpers.STX_DESC:
+			txDesc = count
+		}
+	}
+	return
+}

main.go

@@ -3,6 +3,7 @@ package main
 import (
 	"github.com/LucaBernstein/beancount-bot-tg/bot"
 	"github.com/LucaBernstein/beancount-bot-tg/db"
+	"github.com/LucaBernstein/beancount-bot-tg/web"
 )
 
 func main() {
@@ -12,6 +13,8 @@ func main() {
 	bc := bot.NewBotController(db)
 	bc.ConfigureCronScheduler()
 
+	go web.StartWebServer(bc)
+
 	bot := bot.CreateBot(bc)
 	bc.AddBotAndStart(bot)
 }

web/health/monitoring.go

@@ -0,0 +1,98 @@
+package health
+
+import (
+	"fmt"
+	"net/http"
+
+	"github.com/LucaBernstein/beancount-bot-tg/bot"
+	"github.com/LucaBernstein/beancount-bot-tg/helpers"
+)
+
+type MonitoringResult struct {
+	logs_daily_warning int
+	logs_daily_error   int
+
+	transactions_count_open     int
+	transactions_count_archived int
+
+	users_count int
+
+	cache_entries_accTo   int
+	cache_entries_accFrom int
+	cache_entries_txDesc  int
+}
+
+// TODO: Use package?
+// https://pkg.go.dev/github.com/prometheus/client_golang/prometheus?utm_source=godoc#pkg-overview
+func MonitoringEndpoint(bc *bot.BotController) func(w http.ResponseWriter, r *http.Request) {
+	return func(w http.ResponseWriter, r *http.Request) {
+		m := gatherMetrics(bc)
+		fmt.Fprintf(w, `
+# HELP logs_daily Count of logs of specified type in the previous 24h
+# TYPE logs_daily gauge
+logs_daily{level="error"} %d
+logs_daily{level="warning"} %d
+
+# HELP transactions_count Count of transactions in the database per status
+# TYPE transactions_count gauge
+transactions_count{type="open"} %d
+transactions_count{type="archived"} %d
+
+# HELP users_count Count of unique users by user ID in the database
+# TYPE users_count gauge
+users_count %d
+
+# HELP cache_entries Count of cache entries per type
+# TYPE cache_entries gauge
+cache_entries{type="accTo"} %d
+cache_entries{type="accFrom"} %d
+cache_entries{type="txDesc"} %d
+		`,
+			m.logs_daily_error,
+			m.logs_daily_warning,
+
+			m.transactions_count_open,
+			m.transactions_count_archived,
+
+			m.users_count,
+
+			m.cache_entries_accTo,
+			m.cache_entries_accFrom,
+			m.cache_entries_txDesc,
+		)
+	}
+}
+
+func gatherMetrics(bc *bot.BotController) (result *MonitoringResult) {
+	result = &MonitoringResult{}
+
+	errors, warnings, err := bc.Repo.HealthGetLogs(24)
+	if err != nil {
+		bc.Logf(helpers.ERROR, nil, "Error getting health logs: %s", err.Error())
+	}
+	result.logs_daily_error = errors
+	result.logs_daily_warning = warnings
+
+	open, archived, err := bc.Repo.HealthGetTransactions()
+	if err != nil {
+		bc.Logf(helpers.ERROR, nil, "Error getting health transactions: %s", err.Error())
+	}
+	result.transactions_count_open = open
+	result.transactions_count_archived = archived
+
+	count, err := bc.Repo.HealthGetUserCount()
+	if err != nil {
+		bc.Logf(helpers.ERROR, nil, "Error getting health users: %s", err.Error())
+	}
+	result.users_count = count
+
+	accTo, accFrom, txDesc, err := bc.Repo.HealthGetCacheStats()
+	if err != nil {
+		bc.Logf(helpers.ERROR, nil, "Error getting health transactions: %s", err.Error())
+	}
+	result.cache_entries_accTo = accTo
+	result.cache_entries_accFrom = accFrom
+	result.cache_entries_txDesc = txDesc
+
+	return
+}

web/server.go

@@ -0,0 +1,14 @@
+package web
+
+import (
+	"log"
+	"net/http"
+
+	"github.com/LucaBernstein/beancount-bot-tg/bot"
+	"github.com/LucaBernstein/beancount-bot-tg/web/health"
+)
+
+func StartWebServer(bc *bot.BotController) {
+	http.HandleFunc("/health", health.MonitoringEndpoint(bc))
+	log.Fatal(http.ListenAndServe(":8081", nil))
+}