chore: notify users about failing wakatime connection

middlewares/custom/wakatime.go

@@ -5,18 +5,24 @@ import (
 	"encoding/base64"
 	"fmt"
 	"github.com/emvi/logbuch"
+	"github.com/leandro-lugaresi/hub"
 	"github.com/muety/wakapi/config"
 	"github.com/muety/wakapi/middlewares"
 	"github.com/muety/wakapi/models"
+	"github.com/patrickmn/go-cache"
 	"io"
 	"io/ioutil"
 	"net/http"
 	"time"
 )
 
+const maxFailuresPerDay = 100
+
 /* Middleware to conditionally relay heartbeats to Wakatime */
 type WakatimeRelayMiddleware struct {
-	httpClient *http.Client
+	httpClient   *http.Client
+	failureCache *cache.Cache
+	eventBus     *hub.Hub
 }
 
 func NewWakatimeRelayMiddleware() *WakatimeRelayMiddleware {
@@ -24,6 +30,8 @@ func NewWakatimeRelayMiddleware() *WakatimeRelayMiddleware {
 		httpClient: &http.Client{
 			Timeout: 10 * time.Second,
 		},
+		failureCache: cache.New(24*time.Hour, 1*time.Hour),
+		eventBus:     config.EventBus(),
 	}
 }
 
@@ -92,5 +100,18 @@ func (m *WakatimeRelayMiddleware) send(method, url string, body io.Reader, heade
 
 	if response.StatusCode < 200 || response.StatusCode >= 300 {
 		logbuch.Warn("failed to relay request for user %s, got status %d", forUser.ID, response.StatusCode)
+
+		// TODO: use leaky bucket instead of expiring cache?
+		if _, found := m.failureCache.Get(forUser.ID); !found {
+			m.failureCache.SetDefault(forUser.ID, 0)
+		}
+		if n, _ := m.failureCache.IncrementInt(forUser.ID, 1); n == maxFailuresPerDay {
+			m.eventBus.Publish(hub.Message{
+				Name:   config.EventWakatimeFailure,
+				Fields: map[string]interface{}{config.FieldUser: forUser, config.FieldPayload: n},
+			})
+		} else if n%10 == 0 {
+			logbuch.Warn("%d / %d failed wakatime heartbeat relaying attempts for user %s within last 24 hours", n, maxFailuresPerDay, forUser.ID)
+		}
 	}
 }